gbadisplay: add simple driver for the GameBoy Advance display

This only implements the 15 bits per pixel mode, not any of the other
possible display modes. This matches conventional SPI displays most
closely. Future additions might add more display modes.

Normally I'd argue interfacing with chip/board specific hardware should
be done in the machine package using a generic interface, but the GBA is
kind of special and I don't want the machine package to depend on the
tinygo.org/x/drivers/pixel package.

.github/workflows/build.yml

@@ -11,7 +11,7 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
-    container: ghcr.io/tinygo-org/tinygo-dev
+    container: ghcr.io/tinygo-org/tinygo-dev:latest
     steps:
       - name: Work around CVE-2022-24765
         # We're not on a multi-user machine, so this is safe.

CHANGELOG.md

@@ -1,3 +1,40 @@
+0.26.0
+---
+- **core**
+    - i2c iface refactor: Resolve #559
+    - fix uses of legacy i2c WriteRegister calls
+    - add correct Tx implementation for mock I2C interfaces
+    - bump golang.org/x/net version
+
+- **new devices**
+    - **bma42x**
+        - add new BMA421/BMA425 driver
+    - **ndir**
+        - add Sandbox Electronics NDIR CO2 sensor driver (#580)
+    - **mpu9150**
+        - implement driver for Mpu9150 (#596)
+    - **sht4x**
+        - implement driver for sht4x (#597)
+    - **pcf8523**
+        - implement driver for pcf8523 (#599)
+
+- **enhancements**
+    - **ssd1306**
+        - improve bus error handling
+
+- **bugfixes**
+    - **st7789**
+        - fix scrolling when rotated by 180°
+    - **st7789**
+        - fix incorrect Rotation configuration
+        - fix SetScrollArea
+    - **ili9341**
+        - fix SetScrollArea
+
+- **build**
+    - use latest tag of tinygo-dev container for running tests
+
+
 0.25.0
 ---
 

README.md

@@ -3,7 +3,10 @@
 [![PkgGoDev](https://pkg.go.dev/badge/tinygo.org/x/drivers)](https://pkg.go.dev/tinygo.org/x/drivers) [![Build](https://github.com/tinygo-org/drivers/actions/workflows/build.yml/badge.svg?branch=dev)](https://github.com/tinygo-org/drivers/actions/workflows/build.yml)
 
 
-This package provides a collection of hardware drivers for devices such as sensors and displays that can be used together with [TinyGo](https://tinygo.org).
+This package provides a collection of 101 different hardware drivers for devices such as sensors and displays that can be used together with [TinyGo](https://tinygo.org).
+
+For the complete list, please see:
+https://tinygo.org/docs/reference/devices/
 
 ## Installing
 
@@ -50,11 +53,6 @@ func main() {
 }
 ```
 
-## Supported devices
-
-There are currently 96 devices supported. For the complete list, please see:
-https://tinygo.org/docs/reference/devices/
-
 ## Contributing
 
 Your contributions are welcome!

adafruit4650/device.go

@@ -0,0 +1,196 @@
+// Package adafruit4650 implements a driver for the Adafruit FeatherWing OLED - 128x64 OLED display.
+// The display is backed itself by a SH1107 driver chip.
+//
+// Store: https://www.adafruit.com/product/4650
+//
+// Documentation: https://learn.adafruit.com/adafruit-128x64-oled-featherwing
+package adafruit4650
+
+import (
+	"image/color"
+	"time"
+
+	"tinygo.org/x/drivers"
+)
+
+const DefaultAddress = 0x3c
+
+const (
+	commandSetLowColumn  = 0x00
+	commandSetHighColumn = 0x10
+	commandSetPage       = 0xb0
+)
+
+const (
+	width  = 128
+	height = 64
+)
+
+// Device represents an Adafruit 4650 device
+type Device struct {
+	bus     drivers.I2C
+	Address uint8
+	buffer  []byte
+	width   int16
+	height  int16
+}
+
+// New creates a new device, not configuring anything yet.
+func New(bus drivers.I2C) Device {
+	return Device{
+		bus:     bus,
+		Address: DefaultAddress,
+		width:   width,
+		height:  height,
+	}
+}
+
+// Configure initializes the display with default configuration
+func (d *Device) Configure() error {
+
+	bufferSize := d.width * d.height / 8
+	d.buffer = make([]byte, bufferSize)
+
+	// This sequence is an amalgamation of the datasheet, official Arduino driver, CircuitPython driver and other drivers
+	initSequence := []byte{
+		0xae, // display off, sleep mode
+		//0xd5, 0x41, // set display clock divider (from original datasheet)
+		0xd5, 0x51, // set display clock divider (from Adafruit driver)
+		0xd9, 0x22, // pre-charge/dis-charge period mode: 2 DCLKs/2 DCLKs (POR)
+		0x20,       // memory mode
+		0x81, 0x4f, // contrast setting = 0x4f
+		0xad, 0x8a, // set dc/dc pump
+		0xa0,       // segment remap, flip-x
+		0xc0,       // common output scan direction
+		0xdc, 0x00, // set display start line 0 (POR=0)
+		0xa8, 0x3f, // multiplex ratio, height - 1 = 0x3f
+		0xd3, 0x60, // set display offset mode = 0x60
+		0xdb, 0x35, // VCOM deselect level = 0.770 (POR)
+		0xa4, // entire display off, retain RAM, normal status (POR)
+		0xa6, // normal (not reversed) display
+		0xaf, // display on
+	}
+
+	err := d.writeCommands(initSequence)
+	if err != nil {
+		return err
+	}
+
+	// recommended in the datasheet, same in other drivers
+	time.Sleep(100 * time.Millisecond)
+
+	return nil
+}
+
+// ClearDisplay clears the image buffer as well as the actual display
+func (d *Device) ClearDisplay() error {
+	d.ClearBuffer()
+	return d.Display()
+}
+
+// ClearBuffer clears the buffer
+func (d *Device) ClearBuffer() {
+	bzero(d.buffer)
+}
+
+// SetPixel modifies the internal buffer. Since this display has a bit-depth of 1 bit any non-zero
+// color component will be treated as 'on',  otherwise 'off'.
+func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
+	if x < 0 || x >= d.width || y < 0 || y >= d.height {
+		return
+	}
+
+	// RAM layout
+	//    *-----> y
+	//    |
+	//   x|     col0  col1  ... col63
+	//    v  p0  a0    b0         ..
+	//           a1    b1         ..
+	//           ..    ..         ..
+	//           a7    b7         ..
+	//       p1  a0    b0
+	//           a1    b1
+	//
+
+	//flip y - so the display orientation matches the silk screen labeling etc.
+	y = d.height - y - 1
+
+	page := x / 8
+	bytesPerPage := d.height
+	byteIndex := y + bytesPerPage*page
+	bit := x % 8
+	if (c.R | c.G | c.B) != 0 {
+		d.buffer[byteIndex] |= 1 << uint8(bit)
+	} else {
+		d.buffer[byteIndex] &^= 1 << uint8(bit)
+	}
+}
+
+// Display sends the whole buffer to the screen
+func (d *Device) Display() error {
+
+	bytesPerPage := d.height
+
+	pages := (d.width + 7) / 8
+	for page := int16(0); page < pages; page++ {
+
+		err := d.setRAMPosition(uint8(page), 0)
+		if err != nil {
+			return err
+		}
+
+		offset := page * bytesPerPage
+		err = d.writeRAM(d.buffer[offset : offset+bytesPerPage])
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// setRAMPosition updates the device's current page and column position
+func (d *Device) setRAMPosition(page uint8, column uint8) error {
+	if page > 15 {
+		panic("page out of bounds")
+	}
+	if column > 127 {
+		panic("column out of bounds")
+	}
+	setPage := commandSetPage | (page & 0xF)
+
+	lo := column & 0xF
+	setLowColumn := commandSetLowColumn | lo
+
+	hi := (column >> 4) & 0x7
+	setHighColumn := commandSetHighColumn | hi
+
+	cmds := []byte{
+		setPage,
+		setLowColumn,
+		setHighColumn,
+	}
+
+	return d.writeCommands(cmds)
+}
+
+// Size returns the current size of the display.
+func (d *Device) Size() (w, h int16) {
+	return d.width, d.height
+}
+
+func (d *Device) writeCommands(commands []byte) error {
+	onlyCommandsFollowing := byte(0x00)
+	return d.bus.Tx(uint16(d.Address), append([]byte{onlyCommandsFollowing}, commands...), nil)
+}
+
+func (d *Device) writeRAM(data []byte) error {
+	onlyRAMFollowing := byte(0x40)
+	return d.bus.Tx(uint16(d.Address), append([]byte{onlyRAMFollowing}, data...), nil)
+}
+
+func bzero(buf []byte) {
+	for i := range buf {
+		buf[i] = 0
+	}
+}

adafruit4650/device_test.go

@@ -0,0 +1,176 @@
+package adafruit4650
+
+import (
+	"bytes"
+	_ "embed"
+	"encoding/hex"
+	"fmt"
+	"image"
+	"image/color"
+	"image/draw"
+	"image/png"
+	"os"
+	"testing"
+	"time"
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/tinyfont"
+	"tinygo.org/x/tinyfont/freemono"
+)
+
+//go:embed expected_hello_world.png
+var expectedHelloWorld []byte
+
+// mockBus mocks a fake i2c device adafruit4650 display.
+// The memory layout assumes that clients set up the device in a particular way and always send complete
+// pages to the device buffer.
+type mockBus struct {
+	img           draw.Image
+	line          int
+	addr          uint8
+	currentPage   int
+	currentColumn int
+}
+
+func (m *mockBus) Tx(addr uint16, w, r []byte) error {
+	if addr != uint16(m.addr) {
+		panic("unexpected address")
+	}
+	if r != nil {
+		panic("mock does not support reads")
+	}
+
+	if w[0] == 0x00 {
+		if w[1]&0xf0 == 0xb0 {
+			m.currentPage = int(w[1] & 0x0f)
+
+			lo := w[2] & 0x0f
+			hi := w[2] & 0x07
+			m.currentColumn = int(hi<<4 | lo)
+		}
+		return nil
+	}
+	if w[0] != 0x40 {
+		panic("unexpected first byte: " + hex.EncodeToString(w[0:1]))
+	}
+
+	return m.writeRAM(w[1:])
+}
+
+func newMock() *mockBus {
+
+	m := image.NewRGBA(image.Rect(0, 0, width, height))
+	return &mockBus{img: m, addr: DefaultAddress, currentPage: -1, currentColumn: -1}
+}
+
+func (m *mockBus) writeRAM(data []byte) error {
+
+	// RAM layout
+	//    *-----> y
+	//    |
+	//   x|     col0  col1  ... col63
+	//    v  p0  a0    b0         ..
+	//           a1    b1         ..
+	//           ..    ..         ..
+	//           a7    b7         ..
+	//       p1  a0    b0
+	//           a1    b1
+	//
+
+	fmt.Printf("writing page %d\n", m.currentPage)
+	// assuming entire pages will be written
+	for x := 0; x < 8; x++ {
+		for y := 0; y < height; y++ {
+
+			col := data[y]
+
+			c := color.Black
+			if col&(1<<x) != 0 {
+				c = color.White
+			}
+
+			m.img.Set(x+m.currentPage*8, height-y-1, c)
+		}
+	}
+
+	return nil
+}
+
+func (m *mockBus) toImage() *image.RGBA {
+
+	container := image.NewRGBA(m.img.Bounds().Inset(-1))
+	draw.Draw(container, container.Bounds(), image.NewUniform(color.RGBA{G: 255, A: 255}), image.Point{}, draw.Over)
+	draw.Draw(container, m.img.Bounds(), m.img, image.Point{}, draw.Over)
+	return container
+}
+
+func TestDevice_Display(t *testing.T) {
+
+	bus := newMock()
+	dev := New(bus)
+
+	dev.Configure()
+
+	drawPlus(&dev)
+	drawHellowWorld(&dev)
+
+	//when
+	dev.Display()
+
+	//then
+	actual := bus.toImage()
+
+	expected, err := png.Decode(bytes.NewReader(expectedHelloWorld))
+	if err != nil {
+		panic(err)
+	}
+
+	assertEqualImages(t, actual, expected)
+}
+
+func drawPlus(d drivers.Displayer) {
+	for i := int16(0); i < 128; i++ {
+		d.SetPixel(i, 32, color.RGBA{R: 1})
+	}
+	for i := int16(0); i < 64; i++ {
+		d.SetPixel(64, i, color.RGBA{R: 1})
+	}
+}
+
+func drawHellowWorld(d drivers.Displayer) {
+	tinyfont.WriteLine(d, &freemono.Regular9pt7b, 0, 32, "Hello World!", color.RGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+}
+
+func assertEqualImages(t testing.TB, actual, expected image.Image) {
+
+	if actual.Bounds().Dx() != expected.Bounds().Dx() || actual.Bounds().Dy() != expected.Bounds().Dy() {
+		f := writeImage(actual)
+		t.Fatalf("differing size: was %v, expected %v, saved actual to %s", actual.Bounds(), expected.Bounds(), f)
+	}
+
+	bb := expected.Bounds()
+	for x := bb.Min.X; x < bb.Max.X; x++ {
+		for y := bb.Min.Y; y < bb.Max.Y; y++ {
+			actualBB := actual.Bounds()
+			if actual.At(x+actualBB.Min.X, y+actualBB.Min.Y) != expected.At(x, y) {
+				f := writeImage(actual)
+				t.Fatalf("different pixel at %d/%d: %v != %v, saved actual at %s", x, y, actual.At(x, y), expected.At(x, y), f)
+			}
+		}
+	}
+}
+
+func writeImage(img image.Image) string {
+
+	fn := fmt.Sprintf("%d.png", time.Now().Unix())
+	f, err := os.OpenFile(fn, os.O_RDWR|os.O_CREATE, 0644)
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	err = png.Encode(f, img)
+	if err != nil {
+		panic(err)
+	}
+	return fn
+}

adt7410/adt7410.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type Error uint8
@@ -54,7 +55,7 @@ func (d *Device) Configure() (err error) {
 // Connected returns whether sensor has been found.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), RegID, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), RegID, data)
 	return data[0]&0xF8 == 0xC8
 }
 
@@ -81,11 +82,11 @@ func (d *Device) writeByte(reg uint8, data byte) {
 }
 
 func (d *Device) readByte(reg uint8) byte {
-	d.bus.ReadRegister(d.Address, reg, d.buf)
+	legacy.ReadRegister(d.bus, d.Address, reg, d.buf)
 	return d.buf[0]
 }
 
 func (d *Device) readUint16(reg uint8) uint16 {
-	d.bus.ReadRegister(d.Address, reg, d.buf)
+	legacy.ReadRegister(d.bus, d.Address, reg, d.buf)
 	return uint16(d.buf[0])<<8 | uint16(d.buf[1])
 }

adxl345/adxl345.go

@@ -5,7 +5,10 @@
 // Datasheet JP: http://www.analog.com/media/jp/technical-documentation/data-sheets/ADXL345_jp.pdf
 package adxl345 // import "tinygo.org/x/drivers/adxl345"
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 type Range uint8
 type Rate uint8
@@ -68,21 +71,21 @@ func New(bus drivers.I2C) Device {
 
 // Configure sets up the device for communication
 func (d *Device) Configure() {
-	d.bus.WriteRegister(uint8(d.Address), REG_BW_RATE, []byte{d.bwRate.toByte()})
-	d.bus.WriteRegister(uint8(d.Address), REG_POWER_CTL, []byte{d.powerCtl.toByte()})
-	d.bus.WriteRegister(uint8(d.Address), REG_DATA_FORMAT, []byte{d.dataFormat.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_BW_RATE, []byte{d.bwRate.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_POWER_CTL, []byte{d.powerCtl.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_DATA_FORMAT, []byte{d.dataFormat.toByte()})
 }
 
 // Halt stops the sensor, values will not updated
 func (d *Device) Halt() {
 	d.powerCtl.measure = 0
-	d.bus.WriteRegister(uint8(d.Address), REG_POWER_CTL, []byte{d.powerCtl.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_POWER_CTL, []byte{d.powerCtl.toByte()})
 }
 
 // Restart makes reading the sensor working again after a halt
 func (d *Device) Restart() {
 	d.powerCtl.measure = 1
-	d.bus.WriteRegister(uint8(d.Address), REG_POWER_CTL, []byte{d.powerCtl.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_POWER_CTL, []byte{d.powerCtl.toByte()})
 }
 
 // ReadAcceleration reads the current acceleration from the device and returns
@@ -103,7 +106,7 @@ func (d *Device) ReadAcceleration() (x int32, y int32, z int32, err error) {
 // from the adxl345.
 func (d *Device) ReadRawAcceleration() (x int32, y int32, z int32) {
 	data := []byte{0, 0, 0, 0, 0, 0}
-	d.bus.ReadRegister(uint8(d.Address), REG_DATAX0, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), REG_DATAX0, data)
 
 	x = readIntLE(data[0], data[1])
 	y = readIntLE(data[2], data[3])
@@ -119,20 +122,20 @@ func (d *Device) UseLowPower(power bool) {
 	} else {
 		d.bwRate.lowPower = 0
 	}
-	d.bus.WriteRegister(uint8(d.Address), REG_BW_RATE, []byte{d.bwRate.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_BW_RATE, []byte{d.bwRate.toByte()})
 }
 
 // SetRate change the current rate of the sensor
 func (d *Device) SetRate(rate Rate) bool {
 	d.bwRate.rate = rate & 0x0F
-	d.bus.WriteRegister(uint8(d.Address), REG_BW_RATE, []byte{d.bwRate.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_BW_RATE, []byte{d.bwRate.toByte()})
 	return true
 }
 
 // SetRange change the current range of the sensor
 func (d *Device) SetRange(sensorRange Range) bool {
 	d.dataFormat.sensorRange = sensorRange & 0x03
-	d.bus.WriteRegister(uint8(d.Address), REG_DATA_FORMAT, []byte{d.dataFormat.toByte()})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_DATA_FORMAT, []byte{d.dataFormat.toByte()})
 	return true
 }
 

amg88xx/amg88xx.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a AMG88xx device.
@@ -48,7 +49,7 @@ func (d *Device) Configure(cfg Config) {
 
 // ReadPixels returns the 64 values (8x8 grid) of the sensor converted to  millicelsius
 func (d *Device) ReadPixels(buffer *[64]int16) {
-	d.bus.ReadRegister(uint8(d.Address), PIXEL_OFFSET, d.data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), PIXEL_OFFSET, d.data)
 	for i := 0; i < 64; i++ {
 		buffer[i] = int16((uint16(d.data[2*i+1]) << 8) | uint16(d.data[2*i]))
 		if (buffer[i] & (1 << 11)) > 0 { // temperature negative
@@ -61,17 +62,17 @@ func (d *Device) ReadPixels(buffer *[64]int16) {
 
 // SetPCTL sets the PCTL
 func (d *Device) SetPCTL(pctl uint8) {
-	d.bus.WriteRegister(uint8(d.Address), PCTL, []byte{pctl})
+	legacy.WriteRegister(d.bus, uint8(d.Address), PCTL, []byte{pctl})
 }
 
 // SetReset sets the reset value
 func (d *Device) SetReset(rst uint8) {
-	d.bus.WriteRegister(uint8(d.Address), RST, []byte{rst})
+	legacy.WriteRegister(d.bus, uint8(d.Address), RST, []byte{rst})
 }
 
 // SetFrameRate configures the frame rate
 func (d *Device) SetFrameRate(framerate uint8) {
-	d.bus.WriteRegister(uint8(d.Address), FPSC, []byte{framerate & 0x01})
+	legacy.WriteRegister(d.bus, uint8(d.Address), FPSC, []byte{framerate & 0x01})
 }
 
 // SetMovingAverageMode sets the moving average mode
@@ -80,7 +81,7 @@ func (d *Device) SetMovingAverageMode(mode bool) {
 	if mode {
 		value = 1
 	}
-	d.bus.WriteRegister(uint8(d.Address), AVE, []byte{value << 5})
+	legacy.WriteRegister(d.bus, uint8(d.Address), AVE, []byte{value << 5})
 }
 
 // SetInterruptLevels sets the interrupt levels
@@ -97,8 +98,8 @@ func (d *Device) SetInterruptLevelsHysteresis(high int16, low int16, hysteresis
 	if high > 4095 {
 		high = 4095
 	}
-	d.bus.WriteRegister(uint8(d.Address), INTHL, []byte{uint8(high & 0xFF)})
-	d.bus.WriteRegister(uint8(d.Address), INTHL, []byte{uint8((high & 0xFF) >> 4)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTHL, []byte{uint8(high & 0xFF)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTHL, []byte{uint8((high & 0xFF) >> 4)})
 
 	low = low / PIXEL_TEMP_CONVERSION
 	if low < -4095 {
@@ -107,8 +108,8 @@ func (d *Device) SetInterruptLevelsHysteresis(high int16, low int16, hysteresis
 	if low > 4095 {
 		low = 4095
 	}
-	d.bus.WriteRegister(uint8(d.Address), INTHL, []byte{uint8(low & 0xFF)})
-	d.bus.WriteRegister(uint8(d.Address), INTHL, []byte{uint8((low & 0xFF) >> 4)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTHL, []byte{uint8(low & 0xFF)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTHL, []byte{uint8((low & 0xFF) >> 4)})
 
 	hysteresis = hysteresis / PIXEL_TEMP_CONVERSION
 	if hysteresis < -4095 {
@@ -117,32 +118,32 @@ func (d *Device) SetInterruptLevelsHysteresis(high int16, low int16, hysteresis
 	if hysteresis > 4095 {
 		hysteresis = 4095
 	}
-	d.bus.WriteRegister(uint8(d.Address), INTHL, []byte{uint8(hysteresis & 0xFF)})
-	d.bus.WriteRegister(uint8(d.Address), INTHL, []byte{uint8((hysteresis & 0xFF) >> 4)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTHL, []byte{uint8(hysteresis & 0xFF)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTHL, []byte{uint8((hysteresis & 0xFF) >> 4)})
 }
 
 // EnableInterrupt enables the interrupt pin on the device
 func (d *Device) EnableInterrupt() {
 	d.interruptEnable = 1
-	d.bus.WriteRegister(uint8(d.Address), INTC, []byte{((uint8(d.interruptMode) << 1) | d.interruptEnable) & 0x03})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTC, []byte{((uint8(d.interruptMode) << 1) | d.interruptEnable) & 0x03})
 }
 
 // DisableInterrupt disables the interrupt pin on the device
 func (d *Device) DisableInterrupt() {
 	d.interruptEnable = 0
-	d.bus.WriteRegister(uint8(d.Address), INTC, []byte{((uint8(d.interruptMode) << 1) | d.interruptEnable) & 0x03})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTC, []byte{((uint8(d.interruptMode) << 1) | d.interruptEnable) & 0x03})
 }
 
 // SetInterruptMode sets the interrupt mode
 func (d *Device) SetInterruptMode(mode InterruptMode) {
 	d.interruptMode = mode
-	d.bus.WriteRegister(uint8(d.Address), INTC, []byte{((uint8(d.interruptMode) << 1) | d.interruptEnable) & 0x03})
+	legacy.WriteRegister(d.bus, uint8(d.Address), INTC, []byte{((uint8(d.interruptMode) << 1) | d.interruptEnable) & 0x03})
 }
 
 // GetInterrupt reads the state of the triggered interrupts
 func (d *Device) GetInterrupt() []uint8 {
 	data := make([]uint8, 8)
-	d.bus.ReadRegister(uint8(d.Address), INT_OFFSET, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), INT_OFFSET, data)
 	return data
 }
 
@@ -154,6 +155,6 @@ func (d *Device) ClearInterrupt() {
 // ReadThermistor reads the onboard thermistor
 func (d *Device) ReadThermistor() int16 {
 	data := make([]uint8, 2)
-	d.bus.ReadRegister(uint8(d.Address), TTHL, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), TTHL, data)
 	return (int16((uint16(data[1])<<8)|uint16(data[0])) * THERMISTOR_CONVERSION) / 10
 }

apds9960/apds9960.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a APDS-9960 device.
@@ -68,7 +69,7 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(d.Address, APDS9960_ID_REG, data)
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_ID_REG, data)
 	return data[0] == 0xAB
 }
 
@@ -80,7 +81,7 @@ func (d *Device) GetMode() uint8 {
 // DisableAll turns off the device and all functions
 func (d *Device) DisableAll() {
 	d.enable(enableConfig{})
-	d.bus.WriteRegister(d.Address, APDS9960_GCONF4_REG, []byte{0x00})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_GCONF4_REG, []byte{0x00})
 	d.mode = MODE_NONE
 	d.gesture.detected = GESTURE_NONE
 }
@@ -88,13 +89,13 @@ func (d *Device) DisableAll() {
 // SetProximityPulse sets proximity pulse length (4, 8, 16, 32) and count (1~64)
 // default: 16, 64
 func (d *Device) SetProximityPulse(length, count uint8) {
-	d.bus.WriteRegister(d.Address, APDS9960_PPULSE_REG, []byte{getPulseLength(length)<<6 | getPulseCount(count)})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_PPULSE_REG, []byte{getPulseLength(length)<<6 | getPulseCount(count)})
 }
 
 // SetGesturePulse sets gesture pulse length (4, 8, 16, 32) and count (1~64)
 // default: 16, 64
 func (d *Device) SetGesturePulse(length, count uint8) {
-	d.bus.WriteRegister(d.Address, APDS9960_GPULSE_REG, []byte{getPulseLength(length)<<6 | getPulseCount(count)})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_GPULSE_REG, []byte{getPulseLength(length)<<6 | getPulseCount(count)})
 }
 
 // SetADCIntegrationCycles sets ALS/color ADC internal integration cycles (1~256, 1 cycle = 2.78 ms)
@@ -103,14 +104,14 @@ func (d *Device) SetADCIntegrationCycles(cycles uint16) {
 	if cycles > 256 {
 		cycles = 256
 	}
-	d.bus.WriteRegister(d.Address, APDS9960_ATIME_REG, []byte{uint8(256 - cycles)})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_ATIME_REG, []byte{uint8(256 - cycles)})
 }
 
 // SetGains sets proximity/gesture gain (1, 2, 4, 8x) and ALS/color gain (1, 4, 16, 64x)
 // default: 1, 1, 4
 func (d *Device) SetGains(proximityGain, gestureGain, colorGain uint8) {
-	d.bus.WriteRegister(d.Address, APDS9960_CONTROL_REG, []byte{getProximityGain(proximityGain)<<2 | getALSGain(colorGain)})
-	d.bus.WriteRegister(d.Address, APDS9960_GCONF2_REG, []byte{getProximityGain(gestureGain) << 5})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_CONTROL_REG, []byte{getProximityGain(proximityGain)<<2 | getALSGain(colorGain)})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_GCONF2_REG, []byte{getProximityGain(gestureGain) << 5})
 }
 
 // LEDBoost sets proximity and gesture LED current level (100, 150, 200, 300 (%))
@@ -127,7 +128,7 @@ func (d *Device) LEDBoost(percent uint16) {
 	case 300:
 		v = 3
 	}
-	d.bus.WriteRegister(d.Address, APDS9960_CONFIG2_REG, []byte{0x01 | v<<4})
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_CONFIG2_REG, []byte{0x01 | v<<4})
 }
 
 // Setthreshold sets threshold (0~255) for detecting gestures
@@ -168,7 +169,7 @@ func (d *Device) ReadProximity() (proximity int32) {
 		return 0
 	}
 	data := []byte{0}
-	d.bus.ReadRegister(d.Address, APDS9960_PDATA_REG, data)
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_PDATA_REG, data)
 	return 255 - int32(data[0])
 }
 
@@ -195,14 +196,14 @@ func (d *Device) ReadColor() (r int32, g int32, b int32, clear int32) {
 		return
 	}
 	data := []byte{0, 0, 0, 0, 0, 0, 0, 0}
-	d.bus.ReadRegister(d.Address, APDS9960_CDATAL_REG, data[:1])
-	d.bus.ReadRegister(d.Address, APDS9960_CDATAH_REG, data[1:2])
-	d.bus.ReadRegister(d.Address, APDS9960_RDATAL_REG, data[2:3])
-	d.bus.ReadRegister(d.Address, APDS9960_RDATAH_REG, data[3:4])
-	d.bus.ReadRegister(d.Address, APDS9960_GDATAL_REG, data[4:5])
-	d.bus.ReadRegister(d.Address, APDS9960_GDATAH_REG, data[5:6])
-	d.bus.ReadRegister(d.Address, APDS9960_BDATAL_REG, data[6:7])
-	d.bus.ReadRegister(d.Address, APDS9960_BDATAH_REG, data[7:])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_CDATAL_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_CDATAH_REG, data[1:2])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_RDATAL_REG, data[2:3])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_RDATAH_REG, data[3:4])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_GDATAL_REG, data[4:5])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_GDATAH_REG, data[5:6])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_BDATAL_REG, data[6:7])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_BDATAH_REG, data[7:])
 	clear = int32(uint16(data[1])<<8 | uint16(data[0]))
 	r = int32(uint16(data[3])<<8 | uint16(data[2]))
 	g = int32(uint16(data[5])<<8 | uint16(data[4]))
@@ -234,13 +235,13 @@ func (d *Device) GestureAvailable() bool {
 	data := []byte{0, 0, 0, 0}
 
 	// check GVALID
-	d.bus.ReadRegister(d.Address, APDS9960_GSTATUS_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_GSTATUS_REG, data[:1])
 	if data[0]&0x01 == 0 {
 		return false
 	}
 
 	// get number of data sets available in FIFO
-	d.bus.ReadRegister(d.Address, APDS9960_GFLVL_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_GFLVL_REG, data[:1])
 	availableDataSets := data[0]
 	if availableDataSets == 0 {
 		return false
@@ -249,10 +250,10 @@ func (d *Device) GestureAvailable() bool {
 	// read up, down, left and right proximity data from FIFO
 	var dataSets [32][4]uint8
 	for i := uint8(0); i < availableDataSets; i++ {
-		d.bus.ReadRegister(d.Address, APDS9960_GFIFO_U_REG, data[:1])
-		d.bus.ReadRegister(d.Address, APDS9960_GFIFO_D_REG, data[1:2])
-		d.bus.ReadRegister(d.Address, APDS9960_GFIFO_L_REG, data[2:3])
-		d.bus.ReadRegister(d.Address, APDS9960_GFIFO_R_REG, data[3:4])
+		legacy.ReadRegister(d.bus, d.Address, APDS9960_GFIFO_U_REG, data[:1])
+		legacy.ReadRegister(d.bus, d.Address, APDS9960_GFIFO_D_REG, data[1:2])
+		legacy.ReadRegister(d.bus, d.Address, APDS9960_GFIFO_L_REG, data[2:3])
+		legacy.ReadRegister(d.bus, d.Address, APDS9960_GFIFO_R_REG, data[3:4])
 		for j := uint8(0); j < 4; j++ {
 			dataSets[i][j] = data[j]
 		}
@@ -385,7 +386,7 @@ func (d *Device) enable(cfg enableConfig) {
 	}
 
 	data := []byte{gen<<6 | pien<<5 | aien<<4 | wen<<3 | pen<<2 | aen<<1 | pon}
-	d.bus.WriteRegister(d.Address, APDS9960_ENABLE_REG, data)
+	legacy.WriteRegister(d.bus, d.Address, APDS9960_ENABLE_REG, data)
 
 	if cfg.PON {
 		time.Sleep(time.Millisecond * 10)
@@ -394,7 +395,7 @@ func (d *Device) enable(cfg enableConfig) {
 
 func (d *Device) readStatus(param string) bool {
 	data := []byte{0}
-	d.bus.ReadRegister(d.Address, APDS9960_STATUS_REG, data)
+	legacy.ReadRegister(d.bus, d.Address, APDS9960_STATUS_REG, data)
 
 	switch param {
 	case "CPSAT":

as560x/i2c_register.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // registerAttributes is a bitfield of attributes for a register
@@ -94,7 +95,7 @@ func (r *i2cRegister) readShiftAndMask(bus drivers.I2C, deviceAddress uint8, shi
 			buf = buffer[:]
 		}
 		// Read the host register over I2C
-		err := bus.ReadRegister(deviceAddress, r.host.address, buf)
+		err := legacy.ReadRegister(bus, deviceAddress, r.host.address, buf)
 		if nil != err {
 			return 0, err
 		}
@@ -158,7 +159,7 @@ func (r *i2cRegister) write(bus drivers.I2C, deviceAddress uint8, value uint16)
 	}
 
 	// Write the register from the buffer over I2C
-	err := bus.WriteRegister(deviceAddress, r.host.address, buf)
+	err := legacy.WriteRegister(bus, deviceAddress, r.host.address, buf)
 	// after successful I2C write, cache this value if the host register (if also readable)
 	// Note we cache the entire buffer without applying shift/mask
 	if nil == err && r.host.attributes&reg_read != 0 {

at24cx/at24cx.go

@@ -11,7 +11,7 @@ import (
 	"tinygo.org/x/drivers"
 )
 
-// Device wraps an I2C connection to a DS3231 device.
+// Device wraps an I2C connection to an AT24CX device.
 type Device struct {
 	bus               drivers.I2C
 	Address           uint16

axp192/axp192.go

@@ -7,6 +7,7 @@ package axp192 // import "tinygo.org/x/drivers/axp192"
 
 import (
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type Error uint8
@@ -248,10 +249,10 @@ func (d *Device) SetLDOEnable(number uint8, state bool) {
 }
 
 func (d *Device) write1Byte(reg, data uint8) {
-	d.bus.WriteRegister(d.Address, reg, []byte{data})
+	legacy.WriteRegister(d.bus, d.Address, reg, []byte{data})
 }
 
 func (d *Device) read8bit(reg uint8) uint8 {
-	d.bus.ReadRegister(d.Address, reg, d.buf[:1])
+	legacy.ReadRegister(d.bus, d.Address, reg, d.buf[:1])
 	return d.buf[0]
 }

bma42x/bma42x.go

@@ -0,0 +1,352 @@
+// Package bma42x provides a driver for the BMA421 and BMA425 accelerometer
+// chips.
+//
+// Here is a reasonably good datasheet:
+// https://datasheet.lcsc.com/lcsc/1912111437_Bosch-Sensortec-BMA425_C437656.pdf
+//
+// This driver was originally written for the PineTime, using the datasheet as a
+// guide. There is an open source C driver provided by Bosch, but unfortunately
+// it needs some small modifications to work with other chips (most importantly,
+// the "config file").
+// The InfiniTime and Wasp-OS drivers for this accelerometer have also been used
+// to figure out some driver details (especially step counting).
+package bma42x
+
+import (
+	_ "embed"
+	"errors"
+	"reflect"
+	"time"
+	"unsafe"
+
+	"tinygo.org/x/drivers"
+)
+
+// Driver for BMA421 and BMA425:
+// BMA421: https://files.pine64.org/doc/datasheet/pinetime/BST-BMA421-FL000.pdf
+// BMA425: https://datasheet.lcsc.com/lcsc/1912111437_Bosch-Sensortec-BMA425_C437656.pdf
+
+// This is the BMA421 firmware from the Wasp-OS project.
+// It is identical to the so-called BMA423 firmware in InfiniTime, which I
+// suspect to be actually a BMA421 firmware. I don't know where this firmware
+// comes from or what the licensing status is.
+// It has the FEATURES_IN command prepended, so that it can be written directly
+// using I2C.Tx.
+// Source: https://github.com/wasp-os/bma42x-upy/blob/master/BMA42X-Sensor-API/bma421.h
+//
+//go:embed bma421-config-waspos.bin
+var bma421Firmware string
+
+// Same as the BMA421 firmware, but for the BMA425.
+// Source: https://github.com/wasp-os/bma42x-upy/blob/master/BMA42X-Sensor-API/bma425.h
+//
+//go:embed bma425-config-waspos.bin
+var bma425Firmware string
+
+var (
+	errUnknownDevice     = errors.New("bma42x: unknown device")
+	errUnsupportedDevice = errors.New("bma42x: device not part of config")
+	errConfigMismatch    = errors.New("bma42x: config mismatch")
+	errTimeout           = errors.New("bma42x: timeout")
+	errInitFailed        = errors.New("bma42x: failed to initialize")
+)
+
+const Address = 0x18 // BMA421/BMA425 address
+
+type DeviceType uint8
+
+const (
+	DeviceBMA421 DeviceType = 1 << iota
+	DeviceBMA425
+
+	AnyDevice            = DeviceBMA421 | DeviceBMA425
+	noDevice  DeviceType = 0
+)
+
+// Features to enable while configuring the accelerometer.
+type Features uint8
+
+const (
+	FeatureStepCounting = 1 << iota
+)
+
+type Config struct {
+	// Which devices to support (OR the device types together as needed).
+	Device DeviceType
+
+	// Which features to enable. With Features == 0, only the accelerometer will
+	// be enabled.
+	Features Features
+}
+
+type Device struct {
+	bus               drivers.I2C
+	address           uint8
+	accelData         [6]byte
+	combinedTempSteps [5]uint8 // [0:3] steps, [4] temperature
+	dataBuf           [2]byte
+}
+
+func NewI2C(i2c drivers.I2C, address uint8) *Device {
+	return &Device{
+		bus:     i2c,
+		address: address,
+	}
+}
+
+func (d *Device) Connected() bool {
+	val, err := d.read1(_CHIP_ID)
+	return err == nil && identifyChip(val) != noDevice
+}
+
+func (d *Device) Configure(config Config) error {
+	if config.Device == 0 {
+		config.Device = AnyDevice
+	}
+
+	// Check chip ID, to check the connection and to determine which BMA42x
+	// device we're dealing with.
+	chipID, err := d.read1(_CHIP_ID)
+	if err != nil {
+		return err
+	}
+
+	// Determine which firmware (config file?) we'll be using.
+	// There is an extra check for the device before using the given firmware.
+	// This check will typically be optimized away if the given device is not
+	// configured, so that the firmware (which is 6kB in size!) won't be linked
+	// into the binary.
+	var firmware string
+	switch identifyChip(chipID) {
+	case DeviceBMA421:
+		if config.Device&DeviceBMA421 == 0 {
+			return errUnsupportedDevice
+		}
+		firmware = bma421Firmware
+	case DeviceBMA425:
+		if config.Device&DeviceBMA425 == 0 {
+			return errUnsupportedDevice
+		}
+		firmware = bma425Firmware
+	default:
+		return errUnknownDevice
+	}
+
+	// Reset the chip, to be able to initialize it properly.
+	// The datasheet says a delay is needed after a SoftReset, but it doesn't
+	// say how long this delay should be. The bma423 driver however uses a 200ms
+	// delay, so that's what we'll be using.
+	err = d.write1(_CMD, cmdSoftReset)
+	if err != nil {
+		return err
+	}
+	time.Sleep(200 * time.Millisecond)
+
+	// Disable power saving.
+	err = d.write1(_PWR_CONF, 0x00)
+	if err != nil {
+		return err
+	}
+	time.Sleep(450 * time.Microsecond)
+
+	// Start initialization (because the datasheet says so).
+	err = d.write1(_INIT_CTRL, 0x00)
+	if err != nil {
+		return err
+	}
+
+	// Write "config file" (actually a firmware, I think) to the chip.
+	// To do this, unsafely cast the string to a byte slice to avoid putting it
+	// in RAM. This is safe in this case because Tx won't write to the 'w'
+	// slice.
+	err = d.bus.Tx(uint16(d.address), unsafeStringToSlice(firmware), nil)
+	if err != nil {
+		return err
+	}
+
+	// Read the config data back.
+	// We don't do that, as it slows down configuration and it probably isn't
+	// _really_ necessary with a reasonably stable I2C bus.
+	if false {
+		data := make([]byte, len(firmware)-1)
+		err = d.readn(_FEATURES_IN, data)
+		if err != nil {
+			return err
+		}
+		for i, c := range data {
+			if firmware[i+1] != c {
+				return errConfigMismatch
+			}
+		}
+	}
+
+	// Enable sensors.
+	err = d.write1(_INIT_CTRL, 0x01)
+	if err != nil {
+		return err
+	}
+
+	// Wait until the device is initialized.
+	start := time.Now()
+	status := uint8(0) // busy
+	for status == 0 {
+		status, err = d.read1(_INTERNAL_STATUS)
+		if err != nil {
+			return err // I2C bus error.
+		}
+		if status > 1 {
+			// Expected either 0 ("not_init") or 1 ("init_ok").
+			return errInitFailed
+		}
+		if time.Since(start) >= 150*time.Millisecond {
+			// The datasheet says initialization should not take longer than
+			return errTimeout
+		}
+		// Don't bother the chip all the time while it's initializing.
+		time.Sleep(50 * time.Microsecond)
+	}
+
+	if config.Features&FeatureStepCounting != 0 {
+		// Enable step counter.
+		// TODO: support step counter parameters.
+		var buf [71]byte
+		buf[0] = _FEATURES_IN // prefix buf with the command
+		data := buf[1:]
+		err = d.readn(_FEATURES_IN, data)
+		if err != nil {
+			return err
+		}
+		data[0x3A+1] |= 0x10 // enable step counting by setting a magical bit
+		err = d.bus.Tx(uint16(d.address), buf[:], nil)
+		if err != nil {
+			return err
+		}
+	}
+
+	// Enable the accelerometer.
+	err = d.write1(_PWR_CTRL, 0x04)
+	if err != nil {
+		return err
+	}
+
+	// Configure accelerometer for low power usage:
+	//   acc_perf_mode=0   (power saving enabled)
+	//   acc_bwp=osr4_avg1 (no averaging)
+	//   acc_odr=50Hz      (50Hz sampling interval, enough for the step counter)
+	const accelConf = 0x00<<7 | 0x00<<4 | 0x07<<0
+	err = d.write1(_ACC_CONF, accelConf)
+	if err != nil {
+		return err
+	}
+
+	// Reduce current consumption.
+	// With power saving enabled (and the above ACC_CONF) the chip consumes only
+	// 14µA.
+	err = d.write1(_PWR_CONF, 0x03)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (d *Device) Update(which drivers.Measurement) error {
+	// TODO: combine temperature and step counter into a single read.
+	if which&drivers.Temperature != 0 {
+		val, err := d.read1(_TEMPERATURE)
+		if err != nil {
+			return err
+		}
+		d.combinedTempSteps[4] = val
+	}
+	if which&drivers.Acceleration != 0 {
+		// The acceleration data is stored in DATA8 through DATA13 as 3 12-bit
+		// values.
+		err := d.readn(_DATA_8, d.accelData[:]) // ACC_X(LSB)
+		if err != nil {
+			return err
+		}
+		err = d.readn(_STEP_COUNTER_0, d.combinedTempSteps[:4])
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Temperature returns the last read temperature in celsius milli degrees (1°C
+// is 1000).
+func (d *Device) Temperature() int32 {
+	// The temperature value is a two's complement number (meaning: signed) in
+	// units of 1 kelvin, with 0 being 23°C.
+	return (int32(int8(d.combinedTempSteps[4])) + 23) * 1000
+}
+
+// Acceleration returns the last read acceleration in µg (micro-gravity).
+// When one of the axes is pointing straight to Earth and the sensor is not
+// moving the returned value will be around 1000000 or -1000000.
+func (d *Device) Acceleration() (x, y, z int32) {
+	// Combine raw data from d.accelData (stored as 12-bit signed values) into a
+	// number (0..4095):
+	x = int32(d.accelData[0])>>4 | int32(d.accelData[1])<<4
+	y = int32(d.accelData[2])>>4 | int32(d.accelData[3])<<4
+	z = int32(d.accelData[4])>>4 | int32(d.accelData[5])<<4
+	// Sign extend this number to -2048..2047:
+	x = (x << 20) >> 20
+	y = (y << 20) >> 20
+	z = (z << 20) >> 20
+	// Scale from -512..511 to -1000_000..998_046.
+	// Or, at the maximum range (4g), from -2048..2047 to -2000_000..3998_046.
+	// The formula derived as follows (where 512 is the expected value at 1g):
+	//   x = x * 1000_000      / 512
+	//   x = x * (1000_000/64) / (512/64)
+	//   x = x * 15625         / 8
+	x = x * 15625 / 8
+	y = y * 15625 / 8
+	z = z * 15625 / 8
+	return
+}
+
+// Steps returns the number of steps counted since the BMA42x sensor was
+// initialized.
+func (d *Device) Steps() (steps uint32) {
+	steps |= uint32(d.combinedTempSteps[0]) << 0
+	steps |= uint32(d.combinedTempSteps[1]) << 8
+	steps |= uint32(d.combinedTempSteps[2]) << 16
+	steps |= uint32(d.combinedTempSteps[3]) << 24
+	return
+}
+
+func (d *Device) read1(register uint8) (uint8, error) {
+	d.dataBuf[0] = register
+	err := d.bus.Tx(uint16(d.address), d.dataBuf[:1], d.dataBuf[1:2])
+	return d.dataBuf[1], err
+}
+
+func (d *Device) readn(register uint8, data []byte) error {
+	d.dataBuf[0] = register
+	return d.bus.Tx(uint16(d.address), d.dataBuf[:1], data)
+}
+
+func (d *Device) write1(register uint8, data uint8) error {
+	d.dataBuf[0] = register
+	d.dataBuf[1] = data
+	return d.bus.Tx(uint16(d.address), d.dataBuf[:2], nil)
+}
+
+func unsafeStringToSlice(s string) []byte {
+	// TODO: use unsafe.Slice(unsafe.StringData(...)) once we require Go 1.20.
+	sh := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	return unsafe.Slice((*byte)(unsafe.Pointer(sh.Data)), len(s))
+}
+
+func identifyChip(chipID uint8) DeviceType {
+	switch chipID {
+	case 0x11:
+		return DeviceBMA421
+	case 0x13:
+		return DeviceBMA425
+	default:
+		return noDevice
+	}
+}

bma42x/registers.go

@@ -0,0 +1,73 @@
+package bma42x
+
+const (
+	// I2C registers
+	_CHIP_ID         = 0x00
+	_ERR_REG         = 0x02
+	_STATUS          = 0x03
+	_DATA_0          = 0x0A
+	_DATA_1          = 0x0B
+	_DATA_2          = 0x0C
+	_DATA_3          = 0x0D
+	_DATA_4          = 0x0E
+	_DATA_5          = 0x0F
+	_DATA_6          = 0x10
+	_DATA_7          = 0x11
+	_DATA_8          = 0x12
+	_DATA_9          = 0x13
+	_DATA_10         = 0x14
+	_DATA_11         = 0x15
+	_DATA_12         = 0x16
+	_DATA_13         = 0x17
+	_SENSORTIME_0    = 0x18
+	_SENSORTIME_1    = 0x19
+	_SENSORTIME_2    = 0x1A
+	_EVENT           = 0x1B
+	_INT_STATUS_0    = 0x1C
+	_INT_STATUS_1    = 0x1D
+	_STEP_COUNTER_0  = 0x1E
+	_STEP_COUNTER_1  = 0x1F
+	_STEP_COUNTER_2  = 0x20
+	_STEP_COUNTER_3  = 0x21
+	_TEMPERATURE     = 0x22
+	_FIFO_LENGTH_0   = 0x24
+	_FIFO_LENGTH_1   = 0x25
+	_FIFO_DATA       = 0x26
+	_ACTIVITY_TYPE   = 0x27
+	_INTERNAL_STATUS = 0x2A
+	_ACC_CONF        = 0x40
+	_ACC_RANGE       = 0x41
+	_AUX_CONF        = 0x44
+	_FIFO_DOWNS      = 0x45
+	_FIFO_WTM_0      = 0x46
+	_FIFO_WTM_1      = 0x47
+	_FIFO_CONFIG_0   = 0x48
+	_FIFO_CONFIG_1   = 0x49
+	_AUX_DEV_ID      = 0x4B
+	_AUX_IF_CONF     = 0x4C
+	_AUX_RD_ADDR     = 0x4D
+	_AUX_WR_ADDR     = 0x4E
+	_AUX_WR_DATA     = 0x4F
+	_INT1_IO_CTRL    = 0x53
+	_INT2_IO_CTRL    = 0x54
+	_INT_LATCH       = 0x55
+	_INT1_MAP        = 0x56
+	_INT2_MAP        = 0x57
+	_INT_MAP_DATA    = 0x58
+	_INIT_CTRL       = 0x59
+	_FEATURES_IN     = 0x5E
+	_INTERNAL_ERROR  = 0x5F
+	_NVM_CONF        = 0x6A
+	_IF_CONF         = 0x6B
+	_ACC_SELF_TEST   = 0x6D
+	_NV_CONF         = 0x70
+	_OFFSET_0        = 0x71
+	_OFFSET_1        = 0x72
+	_OFFSET_2        = 0x73
+	_PWR_CONF        = 0x7C
+	_PWR_CTRL        = 0x7D
+	_CMD             = 0x7E
+
+	// Commands send to regCommand.
+	cmdSoftReset = 0xB6
+)

bme280/bme280.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // calibrationCoefficients reads at startup and stores the calibration coefficients
@@ -98,19 +99,19 @@ func (d *Device) ConfigureWithSettings(config Config) {
 	}
 
 	var data [24]byte
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CALIBRATION, data[:])
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CALIBRATION, data[:])
 	if err != nil {
 		return
 	}
 
 	var h1 [1]byte
-	err = d.bus.ReadRegister(uint8(d.Address), REG_CALIBRATION_H1, h1[:])
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), REG_CALIBRATION_H1, h1[:])
 	if err != nil {
 		return
 	}
 
 	var h2lsb [7]byte
-	err = d.bus.ReadRegister(uint8(d.Address), REG_CALIBRATION_H2LSB, h2lsb[:])
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), REG_CALIBRATION_H2LSB, h2lsb[:])
 	if err != nil {
 		return
 	}
@@ -137,12 +138,12 @@ func (d *Device) ConfigureWithSettings(config Config) {
 
 	d.Reset()
 
-	d.bus.WriteRegister(uint8(d.Address), CTRL_CONFIG, []byte{byte(d.Config.Period<<5) | byte(d.Config.IIR<<2)})
-	d.bus.WriteRegister(uint8(d.Address), CTRL_HUMIDITY_ADDR, []byte{byte(d.Config.Humidity)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_CONFIG, []byte{byte(d.Config.Period<<5) | byte(d.Config.IIR<<2)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_HUMIDITY_ADDR, []byte{byte(d.Config.Humidity)})
 
 	// Normal mode, start measuring now
 	if d.Config.Mode == ModeNormal {
-		d.bus.WriteRegister(uint8(d.Address), CTRL_MEAS_ADDR, []byte{
+		legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_MEAS_ADDR, []byte{
 			byte(d.Config.Temperature<<5) |
 				byte(d.Config.Pressure<<2) |
 				byte(d.Config.Mode)})
@@ -153,13 +154,13 @@ func (d *Device) ConfigureWithSettings(config Config) {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == CHIP_ID
 }
 
 // Reset the device
 func (d *Device) Reset() {
-	d.bus.WriteRegister(uint8(d.Address), CMD_RESET, []byte{0xB6})
+	legacy.WriteRegister(d.bus, uint8(d.Address), CMD_RESET, []byte{0xB6})
 }
 
 // SetMode can set the device to Sleep, Normal or Forced mode
@@ -170,7 +171,7 @@ func (d *Device) Reset() {
 func (d *Device) SetMode(mode Mode) {
 	d.Config.Mode = mode
 
-	d.bus.WriteRegister(uint8(d.Address), CTRL_MEAS_ADDR, []byte{
+	legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_MEAS_ADDR, []byte{
 		byte(d.Config.Temperature<<5) |
 			byte(d.Config.Pressure<<2) |
 			byte(d.Config.Mode)})
@@ -252,7 +253,7 @@ func readIntLE(msb byte, lsb byte) int16 {
 func (d *Device) readData() (data [8]byte, err error) {
 	if d.Config.Mode == ModeForced {
 		// Write the CTRL_MEAS register to trigger a measurement
-		d.bus.WriteRegister(uint8(d.Address), CTRL_MEAS_ADDR, []byte{
+		legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_MEAS_ADDR, []byte{
 			byte(d.Config.Temperature<<5) |
 				byte(d.Config.Pressure<<2) |
 				byte(d.Config.Mode)})
@@ -260,7 +261,7 @@ func (d *Device) readData() (data [8]byte, err error) {
 		time.Sleep(d.measurementDelay())
 	}
 
-	err = d.bus.ReadRegister(uint8(d.Address), REG_PRESSURE, data[:])
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), REG_PRESSURE, data[:])
 	if err != nil {
 		println(err)
 		return

bmp180/bmp180.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // OversamplingMode is the oversampling ratio of the pressure measurement.
@@ -55,7 +56,7 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == CHIP_ID
 }
 
@@ -63,7 +64,7 @@ func (d *Device) Connected() bool {
 // read the calibration coefficients.
 func (d *Device) Configure() {
 	data := make([]byte, 22)
-	err := d.bus.ReadRegister(uint8(d.Address), AC1_MSB, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), AC1_MSB, data)
 	if err != nil {
 		return
 	}
@@ -141,10 +142,10 @@ func (d *Device) ReadAltitude() (int32, error) {
 
 // rawTemp returns the sensor's raw values of the temperature
 func (d *Device) rawTemp() (int32, error) {
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL, []byte{CMD_TEMP})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL, []byte{CMD_TEMP})
 	time.Sleep(5 * time.Millisecond)
 	data := make([]byte, 2)
-	err := d.bus.ReadRegister(uint8(d.Address), REG_TEMP_MSB, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_TEMP_MSB, data)
 	if err != nil {
 		return 0, err
 	}
@@ -160,10 +161,10 @@ func (d *Device) calculateB5(rawTemp int32) int32 {
 
 // rawPressure returns the sensor's raw values of the pressure
 func (d *Device) rawPressure(mode OversamplingMode) (int32, error) {
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL, []byte{CMD_PRESSURE + byte(mode<<6)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL, []byte{CMD_PRESSURE + byte(mode<<6)})
 	time.Sleep(pauseForReading(mode))
 	data := make([]byte, 3)
-	err := d.bus.ReadRegister(uint8(d.Address), REG_PRESSURE_MSB, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_PRESSURE_MSB, data)
 	if err != nil {
 		return 0, err
 	}

bmp280/bmp280.go

@@ -4,6 +4,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // OversamplingMode is the oversampling ratio of the temperature or pressure measurement.
@@ -64,14 +65,14 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := make([]byte, 1)
-	d.bus.ReadRegister(uint8(d.Address), REG_ID, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), REG_ID, data)
 	return data[0] == CHIP_ID
 }
 
 // Reset preforms complete power-on-reset procedure.
 // It is required to call Configure afterwards.
 func (d *Device) Reset() {
-	d.bus.WriteRegister(uint8(d.Address), REG_RESET, []byte{CMD_RESET})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_RESET, []byte{CMD_RESET})
 }
 
 // Configure sets up the device for communication and
@@ -85,15 +86,15 @@ func (d *Device) Configure(standby Standby, filter Filter, temp Oversampling, pr
 
 	//  Write the configuration (standby, filter, spi 3 wire)
 	config := uint(d.Standby<<5) | uint(d.Filter<<2) | 0x00
-	d.bus.WriteRegister(uint8(d.Address), REG_CONFIG, []byte{byte(config)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CONFIG, []byte{byte(config)})
 
 	// Write the control (temperature oversampling, pressure oversampling,
 	config = uint(d.Temperature<<5) | uint(d.Pressure<<2) | uint(d.Mode)
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL_MEAS, []byte{byte(config)})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL_MEAS, []byte{byte(config)})
 
 	// Read Calibration data
 	data := make([]byte, 24)
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CALI, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CALI, data)
 	if err != nil {
 		return
 	}
@@ -207,18 +208,18 @@ func (d *Device) readData(register int, n int) ([]byte, error) {
 	// After the measurement in FORCED mode, the sensor will return to SLEEP mode
 	if d.Mode != MODE_NORMAL {
 		config := uint(d.Temperature<<5) | uint(d.Pressure<<2) | uint(MODE_FORCED)
-		d.bus.WriteRegister(uint8(d.Address), REG_CTRL_MEAS, []byte{byte(config)})
+		legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL_MEAS, []byte{byte(config)})
 	}
 
 	// Check STATUS register, wait if data is not available yet
 	status := make([]byte, 1)
-	for d.bus.ReadRegister(uint8(d.Address), uint8(REG_STATUS), status[0:]); status[0] != 4 && status[0] != 0; d.bus.ReadRegister(uint8(d.Address), uint8(REG_STATUS), status[0:]) {
+	for legacy.ReadRegister(d.bus, uint8(d.Address), uint8(REG_STATUS), status[0:]); status[0] != 4 && status[0] != 0; legacy.ReadRegister(d.bus, uint8(d.Address), uint8(REG_STATUS), status[0:]) {
 		time.Sleep(time.Millisecond)
 	}
 
 	// Read the requested register
 	data := make([]byte, n)
-	err := d.bus.ReadRegister(uint8(d.Address), uint8(register), data[:])
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), uint8(register), data[:])
 	return data, err
 }
 

bmp388/bmp388.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 var (
@@ -240,10 +241,10 @@ func (d *Device) configurationError() bool {
 
 func (d *Device) readRegister(register byte, len int) (data []byte, err error) {
 	data = make([]byte, len)
-	err = d.bus.ReadRegister(d.Address, register, data)
+	err = legacy.ReadRegister(d.bus, d.Address, register, data)
 	return
 }
 
 func (d *Device) writeRegister(register byte, data byte) error {
-	return d.bus.WriteRegister(d.Address, register, []byte{data})
+	return legacy.WriteRegister(d.bus, d.Address, register, []byte{data})
 }

delay/sleep.go

@@ -49,7 +49,7 @@ func Sleep(duration time.Duration) {
 	//   * The CPU frequency is lower than 256MHz. If it is higher, long sleep
 	//     times (1-16ms) may not work correctly.
 	cycles := uint32(duration) * (machine.CPUFrequency() / 1000_000) / 1000
-	slept := C.tinygo_drivers_sleep(cycles)
+	slept := C.tinygo_drivers_sleep(C.uint32_t(cycles))
 	if !slept {
 		// Fallback for platforms without inline assembly support.
 		time.Sleep(duration)

ds1307/ds1307.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a DS1307 device.
@@ -44,7 +45,7 @@ func (d *Device) SetTime(t time.Time) error {
 // ReadTime returns the date and time
 func (d *Device) ReadTime() (time.Time, error) {
 	data := make([]byte, 8)
-	err := d.bus.ReadRegister(d.Address, uint8(TimeDate), data)
+	err := legacy.ReadRegister(d.bus, d.Address, uint8(TimeDate), data)
 	if err != nil {
 		return time.Time{}, err
 	}
@@ -105,7 +106,7 @@ func (d *Device) Read(data []uint8) (n int, err error) {
 	if int(d.AddressSRAM)+len(data)-1 > SRAMEndAddress {
 		return 0, errors.New("EOF")
 	}
-	err = d.bus.ReadRegister(d.Address, d.AddressSRAM, data)
+	err = legacy.ReadRegister(d.bus, d.Address, d.AddressSRAM, data)
 	if err != nil {
 		return 0, err
 	}
@@ -124,7 +125,7 @@ func (d *Device) SetOscillatorFrequency(sqw uint8) error {
 // IsOscillatorRunning returns if the oscillator is running
 func (d *Device) IsOscillatorRunning() bool {
 	data := []byte{0}
-	err := d.bus.ReadRegister(d.Address, uint8(TimeDate), data)
+	err := legacy.ReadRegister(d.bus, d.Address, uint8(TimeDate), data)
 	if err != nil {
 		return false
 	}
@@ -134,7 +135,7 @@ func (d *Device) IsOscillatorRunning() bool {
 // SetOscillatorRunning starts/stops internal oscillator by toggling halt bit
 func (d *Device) SetOscillatorRunning(running bool) error {
 	data := make([]byte, 3)
-	err := d.bus.ReadRegister(d.Address, uint8(TimeDate), data)
+	err := legacy.ReadRegister(d.bus, d.Address, uint8(TimeDate), data)
 	if err != nil {
 		return err
 	}

ds3231/ds3231.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type Mode uint8
@@ -37,7 +38,7 @@ func (d *Device) Configure() bool {
 // IsTimeValid return true/false is the time in the device is valid
 func (d *Device) IsTimeValid() bool {
 	data := []byte{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_STATUS, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_STATUS, data)
 	if err != nil {
 		return false
 	}
@@ -47,7 +48,7 @@ func (d *Device) IsTimeValid() bool {
 // IsRunning returns if the oscillator is running
 func (d *Device) IsRunning() bool {
 	data := []uint8{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CONTROL, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CONTROL, data)
 	if err != nil {
 		return false
 	}
@@ -57,7 +58,7 @@ func (d *Device) IsRunning() bool {
 // SetRunning starts the internal oscillator
 func (d *Device) SetRunning(isRunning bool) error {
 	data := []uint8{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CONTROL, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CONTROL, data)
 	if err != nil {
 		return err
 	}
@@ -66,7 +67,7 @@ func (d *Device) SetRunning(isRunning bool) error {
 	} else {
 		data[0] |= 1 << EOSC
 	}
-	err = d.bus.WriteRegister(uint8(d.Address), REG_CONTROL, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), REG_CONTROL, data)
 	if err != nil {
 		return err
 	}
@@ -86,12 +87,12 @@ func (d *Device) SetRunning(isRunning bool) error {
 // instead of 2100-03-01.
 func (d *Device) SetTime(dt time.Time) error {
 	data := []byte{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_STATUS, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_STATUS, data)
 	if err != nil {
 		return err
 	}
 	data[0] &^= 1 << OSF
-	err = d.bus.WriteRegister(uint8(d.Address), REG_STATUS, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), REG_STATUS, data)
 	if err != nil {
 		return err
 	}
@@ -117,7 +118,7 @@ func (d *Device) SetTime(dt time.Time) error {
 	data[5] = uint8ToBCD(uint8(dt.Month()) | centuryFlag)
 	data[6] = uint8ToBCD(year)
 
-	err = d.bus.WriteRegister(uint8(d.Address), REG_TIMEDATE, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), REG_TIMEDATE, data)
 	if err != nil {
 		return err
 	}
@@ -128,7 +129,7 @@ func (d *Device) SetTime(dt time.Time) error {
 // ReadTime returns the date and time
 func (d *Device) ReadTime() (dt time.Time, err error) {
 	data := make([]uint8, 7)
-	err = d.bus.ReadRegister(uint8(d.Address), REG_TIMEDATE, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), REG_TIMEDATE, data)
 	if err != nil {
 		return
 	}
@@ -150,7 +151,7 @@ func (d *Device) ReadTime() (dt time.Time, err error) {
 // ReadTemperature returns the temperature in millicelsius (mC)
 func (d *Device) ReadTemperature() (int32, error) {
 	data := make([]uint8, 2)
-	err := d.bus.ReadRegister(uint8(d.Address), REG_TEMP, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_TEMP, data)
 	if err != nil {
 		return 0, err
 	}

examples/adafruit4650/main.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"image/color"
+	"machine"
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/adafruit4650"
+	"tinygo.org/x/tinyfont"
+	"tinygo.org/x/tinyfont/freemono"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+
+	dev := adafruit4650.New(machine.I2C0)
+
+	err := dev.Configure()
+	if err != nil {
+		panic(err)
+	}
+
+	drawPlus(&dev)
+	drawHelloWorld(&dev)
+
+	err = dev.Display()
+	if err != nil {
+		panic(err)
+	}
+}
+
+func drawPlus(d drivers.Displayer) {
+	for i := int16(0); i < 128; i++ {
+		d.SetPixel(i, 32, color.RGBA{R: 1})
+	}
+	for i := int16(0); i < 64; i++ {
+		d.SetPixel(64, i, color.RGBA{R: 1})
+	}
+}
+
+func drawHelloWorld(d drivers.Displayer) {
+	tinyfont.WriteLine(d, &freemono.Regular9pt7b, 0, 32, "Hello World!", color.RGBA{R: 0xff, G: 0xff, B: 0xff, A: 0xff})
+}

examples/bma42x/main.go

@@ -0,0 +1,54 @@
+package main
+
+// Smoke test for the BMA421/BMA425 sensors.
+// Warning: this code has _not been tested_. It's only here as a smoke test.
+
+import (
+	"fmt"
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/bma42x"
+)
+
+func main() {
+	time.Sleep(5 * time.Second)
+
+	i2cBus := machine.I2C1
+	i2cBus.Configure(machine.I2CConfig{
+		Frequency: 400 * machine.KHz,
+		SDA:       machine.SDA_PIN,
+		SCL:       machine.SCL_PIN,
+	})
+
+	sensor := bma42x.NewI2C(i2cBus, bma42x.Address)
+	err := sensor.Configure(bma42x.Config{
+		Device:   bma42x.DeviceBMA421 | bma42x.DeviceBMA425,
+		Features: bma42x.FeatureStepCounting,
+	})
+	if err != nil {
+		println("could not configure BMA421/BMA425:", err)
+		return
+	}
+
+	if !sensor.Connected() {
+		println("BMA42x not connected")
+		return
+	}
+
+	for {
+		time.Sleep(time.Second)
+
+		err := sensor.Update(drivers.Acceleration | drivers.Temperature)
+		if err != nil {
+			println("Error reading sensor", err)
+			continue
+		}
+
+		fmt.Printf("Temperature: %.2f °C\n", float32(sensor.Temperature())/1000)
+
+		accelX, accelY, accelZ := sensor.Acceleration()
+		fmt.Printf("Acceleration: %.2fg %.2fg %.2fg\n", float32(accelX)/1e6, float32(accelY)/1e6, float32(accelZ)/1e6)
+	}
+}

examples/ds3231/main.go

@@ -1,4 +1,4 @@
-// Connects to an MAG3110 I2C magnetometer.
+// Connects to an DS3231 I2C Real Time Clock (RTC).
 package main
 
 import (

examples/ili9341/pyportal_boing/main.go

@@ -8,15 +8,16 @@ import (
 	"tinygo.org/x/drivers/examples/ili9341/initdisplay"
 	"tinygo.org/x/drivers/examples/ili9341/pyportal_boing/graphics"
 	"tinygo.org/x/drivers/ili9341"
+	"tinygo.org/x/drivers/pixel"
 )
 
 const (
-	BGCOLOR    = 0xAD75
-	GRIDCOLOR  = 0xA815
-	BGSHADOW   = 0x5285
-	GRIDSHADOW = 0x600C
-	RED        = 0xF800
-	WHITE      = 0xFFFF
+	BGCOLOR    = pixel.RGB565BE(0x75AD)
+	GRIDCOLOR  = pixel.RGB565BE(0x15A8)
+	BGSHADOW   = pixel.RGB565BE(0x8552)
+	GRIDSHADOW = pixel.RGB565BE(0x0C60)
+	RED        = pixel.RGB565BE(0x00F8)
+	WHITE      = pixel.RGB565BE(0xFFFF)
 
 	YBOTTOM = 123  // Ball Y coord at bottom
 	YBOUNCE = -3.5 // Upward velocity on ball bounce
@@ -25,7 +26,7 @@ const (
 )
 
 var (
-	frameBuffer = [(graphics.BALLHEIGHT + 8) * (graphics.BALLWIDTH + 8) * 2]uint8{}
+	frameBuffer = pixel.NewImage[pixel.RGB565BE](graphics.BALLWIDTH+8, graphics.BALLHEIGHT+8)
 
 	startTime int64
 	frame     int64
@@ -41,7 +42,7 @@ var (
 	balloldy  float32
 
 	// Color table for ball rotation effect
-	palette [16]uint16
+	palette [16]pixel.RGB565BE
 )
 
 var (
@@ -108,6 +109,7 @@ func main() {
 
 		width = maxx - minx + 1
 		height = maxy - miny + 1
+		buffer := frameBuffer.Rescale(int(width), int(height))
 
 		// Ball animation frame # is incremented opposite the ball's X velocity
 		ballframe -= ballvx * 0.5
@@ -128,7 +130,7 @@ func main() {
 		}
 
 		// Only the changed rectangle is drawn into the 'renderbuf' array...
-		var c uint16              //, *destPtr;
+		var c pixel.RGB565BE      //, *destPtr;
 		bx := minx - int16(ballx) // X relative to ball bitmap (can be negative)
 		by := miny - int16(bally) // Y relative to ball bitmap (can be negative)
 		bgx := minx               // X relative to background bitmap (>= 0)
@@ -149,19 +151,20 @@ func main() {
 					(by >= 0) && (by < graphics.BALLHEIGHT) { // inside the ball bitmap area?
 					// Yes, do ball compositing math...
 					p = graphics.Ball[int(by*(graphics.BALLWIDTH/2))+int(bx1/2)] // Get packed value (2 pixels)
+					var nibble uint8
 					if (bx1 & 1) != 0 {
-						c = uint16(p & 0xF)
+						nibble = p & 0xF
 					} else {
-						c = uint16(p >> 4)
+						nibble = p >> 4
 					} // Unpack high or low nybble
-					if c == 0 { // Outside ball - just draw grid
+					if nibble == 0 { // Outside ball - just draw grid
 						if graphics.Background[bgidx]&(0x80>>(bgx1&7)) != 0 {
 							c = GRIDCOLOR
 						} else {
 							c = BGCOLOR
 						}
-					} else if c > 1 { // In ball area...
-						c = palette[c]
+					} else if nibble > 1 { // In ball area...
+						c = palette[nibble]
 					} else { // In shadow area...
 						if graphics.Background[bgidx]&(0x80>>(bgx1&7)) != 0 {
 							c = GRIDSHADOW
@@ -176,8 +179,7 @@ func main() {
 						c = BGCOLOR
 					}
 				}
-				frameBuffer[(y*int(width)+x)*2] = byte(c >> 8)
-				frameBuffer[(y*int(width)+x)*2+1] = byte(c)
+				buffer.Set(x, y, c)
 				bx1++ // Increment bitmap position counters (X axis)
 				bgx1++
 			}
@@ -188,7 +190,7 @@ func main() {
 			bgy++
 		}
 
-		display.DrawRGBBitmap8(minx, miny, frameBuffer[:width*height*2], width, height)
+		display.DrawBitmap(minx, miny, buffer)
 
 		// Show approximate frame rate
 		frame++
@@ -205,6 +207,7 @@ func DrawBackground() {
 	w, h := display.Size()
 	byteWidth := (w + 7) / 8 // Bitmap scanline pad = whole byte
 	var b uint8
+	buffer := frameBuffer.Rescale(int(w), 1)
 	for j := int16(0); j < h; j++ {
 		for k := int16(0); k < w; k++ {
 			if k&7 > 0 {
@@ -213,13 +216,11 @@ func DrawBackground() {
 				b = graphics.Background[j*byteWidth+k/8]
 			}
 			if b&0x80 == 0 {
-				frameBuffer[2*k] = byte(BGCOLOR >> 8)
-				frameBuffer[2*k+1] = byte(BGCOLOR & 0xFF)
+				buffer.Set(int(k), 0, BGCOLOR)
 			} else {
-				frameBuffer[2*k] = byte(GRIDCOLOR >> 8)
-				frameBuffer[2*k+1] = byte(GRIDCOLOR & 0xFF)
+				buffer.Set(int(k), 0, GRIDCOLOR)
 			}
 		}
-		display.DrawRGBBitmap8(0, j, frameBuffer[0:w*2], w, 1)
+		display.DrawBitmap(0, j, buffer)
 	}
 }

examples/lora/lorawan/atcmd/README.md

@@ -23,20 +23,20 @@ Builds/flashes atcmd console application with simulator instead of actual LoRa r
 tinygo flash -target pico ./examples/lora/lorawan/atcmd/
 ```
 
-## PyBadge with LoRa Featherwing 
+## PyBadge with LoRa Featherwing for EU868 region
 
 Builds/flashes atcmd console application on PyBadge using LoRa Featherwing (RFM95/SX1276).
 
 ```
-tinygo flash -target pybadge -tags featherwing ./examples/lora/lorawan/atcmd/
+tinygo flash -target pybadge -tags featherwing -ldflags="-X main.reg=EU868" ./examples/lora/lorawan/atcmd/
 ```
 
-## LoRa-E5 
+## LoRa-E5 for US915 region
 
 Builds/flashes atcmd console application on Lora-E5 using onboard SX126x.
 
 ```
-tinygo flash -target lorae5 ./examples/lora/lorawan/atcmd/
+tinygo flash -target lorae5 -ldflags="-X main.reg=US915" ./examples/lora/lorawan/atcmd/
 ```
 
 ## Joining a Public Lorawan Network

examples/lora/lorawan/atcmd/main.go

@@ -32,6 +32,8 @@ var (
 	defaultTimeout uint32 = 1000
 )
 
+var reg string
+
 func main() {
 	uart.Configure(machine.UARTConfig{TX: tx, RX: rx})
 
@@ -45,7 +47,16 @@ func main() {
 	otaa = &lorawan.Otaa{}
 	lorawan.UseRadio(radio)
 
-	lorawan.UseRegionSettings(region.EU868())
+	switch reg {
+	case "AU915":
+		lorawan.UseRegionSettings(region.AU915())
+	case "EU868":
+		lorawan.UseRegionSettings(region.EU868())
+	case "US915":
+		lorawan.UseRegionSettings(region.US915())
+	default:
+		lorawan.UseRegionSettings(region.EU868())
+	}
 
 	for {
 		if uart.Buffered() > 0 {

examples/lora/lorawan/basic-demo/README.md

@@ -21,16 +21,16 @@ loraConnect: Connected !
 tinygo flash -target pico ./examples/lora/lorawan/basic-demo
 ```
 
-## PyBadge with LoRa Featherwing 
+## PyBadge with LoRa Featherwing for EU868 region
 
 ```
-tinygo flash -target pybadge -tags featherwing ./examples/lora/lorawan/basic-demo
+tinygo flash -target pybadge -tags featherwing -ldflags="-X main.reg=EU868" ./examples/lora/lorawan/basic-demo
 ```
 
-## LoRa-E5 
+## LoRa-E5 for US915 region
 
 ```
-tinygo flash -target lorae5 ./examples/lora/lorawan/basic-demo
+tinygo flash -target lorae5 -ldflags="-X main.reg=US915" ./examples/lora/lorawan/basic-demo
 ```
 
 

examples/lora/lorawan/basic-demo/main.go

@@ -12,7 +12,10 @@ import (
 	"tinygo.org/x/drivers/lora/lorawan/region"
 )
 
-var debug string
+var (
+	reg   string
+	debug string
+)
 
 const (
 	LORAWAN_JOIN_TIMEOUT_SEC    = 180
@@ -67,8 +70,16 @@ func main() {
 
 	// Connect the lorawan with the Lora Radio device.
 	lorawan.UseRadio(radio)
-
-	lorawan.UseRegionSettings(region.EU868())
+	switch reg {
+	case "AU915":
+		lorawan.UseRegionSettings(region.AU915())
+	case "EU868":
+		lorawan.UseRegionSettings(region.EU868())
+	case "US915":
+		lorawan.UseRegionSettings(region.US915())
+	default:
+		lorawan.UseRegionSettings(region.EU868())
+	}
 
 	// Configure AppEUI, DevEUI, APPKey, and public/private Lorawan Network
 	setLorawanKeys()

examples/lora/lorawan/common/sim.go

@@ -23,13 +23,18 @@ func (sr *SimLoraRadio) Rx(timeoutMs uint32) ([]uint8, error) {
 	return nil, nil
 }
 
-func (sr *SimLoraRadio) SetFrequency(freq uint32)    {}
-func (sr *SimLoraRadio) SetIqMode(mode uint8)        {}
-func (sr *SimLoraRadio) SetCodingRate(cr uint8)      {}
-func (sr *SimLoraRadio) SetBandwidth(bw uint8)       {}
-func (sr *SimLoraRadio) SetCrc(enable bool)          {}
-func (sr *SimLoraRadio) SetSpreadingFactor(sf uint8) {}
-func (sr *SimLoraRadio) LoraConfig(cnf lora.Config)  {}
+func (sr *SimLoraRadio) SetFrequency(freq uint32)       {}
+func (sr *SimLoraRadio) SetIqMode(mode uint8)           {}
+func (sr *SimLoraRadio) SetCodingRate(cr uint8)         {}
+func (sr *SimLoraRadio) SetBandwidth(bw uint8)          {}
+func (sr *SimLoraRadio) SetCrc(enable bool)             {}
+func (sr *SimLoraRadio) SetSpreadingFactor(sf uint8)    {}
+func (sr *SimLoraRadio) SetHeaderType(headerType uint8) {}
+func (sr *SimLoraRadio) SetPreambleLength(pLen uint16)  {}
+func (sr *SimLoraRadio) SetPublicNetwork(enabled bool)  {}
+func (sr *SimLoraRadio) SetSyncWord(syncWord uint16)    {}
+func (sr *SimLoraRadio) SetTxPower(txPower int8)        {}
+func (sr *SimLoraRadio) LoraConfig(cnf lora.Config)     {}
 
 func FirmwareVersion() string {
 	return "simulator " + CurrentVersion()

examples/mpu9150/main.go

@@ -0,0 +1,22 @@
+// Connects to an MPU9150 I2C accelerometer/gyroscope.
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/mpu9150"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+
+	accel := mpu9150.New(machine.I2C0)
+	accel.Configure()
+
+	for {
+		x, y, z := accel.ReadAcceleration(mpu9150.ACCEL_XOUT_H)
+		println(x, y, z)
+		time.Sleep(time.Millisecond * 100)
+	}
+}

examples/ndir/main_ndir.go

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/ndir"
+)
+
+var (
+	ndirBus = machine.I2C0
+)
+
+func main() {
+	err := ndirBus.Configure(machine.I2CConfig{
+		Frequency: 100_000,
+	})
+	if err != nil {
+		panic("i2c config fail:" + err.Error())
+	}
+	// Set the address based on how the resistors are soldered.
+	// True means the left and middle pads are joined.
+	ndirAddr := ndir.Addr(true, false)
+	dev := ndir.NewDevI2C(ndirBus, ndirAddr)
+	err = dev.Init()
+	if err != nil {
+		panic("ndir init fail:" + err.Error())
+	}
+	// Datasheet tells us to wait 12 seconds before reading from the sensor.
+	time.Sleep(12 * time.Second)
+	for {
+		time.Sleep(time.Second)
+		err := dev.Update(drivers.AllMeasurements)
+		if err != nil {
+			println(err.Error())
+			continue
+		}
+		println("PPM:", dev.PPMCO2())
+	}
+}

examples/pcf8523/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"machine"
+	"time"
+	"tinygo.org/x/drivers/pcf8523"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+	dev := pcf8523.New(machine.I2C0)
+
+	// make sure the battery takes over if power is lost
+	err := dev.SetPowerManagement(pcf8523.PowerManagement_SwitchOver_ModeStandard)
+	if err != nil {
+		panic(err)
+	}
+
+	// set RTC once, i.e. from `date -u +"%Y-%m-%dT%H:%M:%SZ"`
+	now, _ := time.Parse(time.RFC3339, "2023-09-18T20:31:38Z")
+	err = dev.SetTime(now)
+	if err != nil {
+		panic(err)
+	}
+
+	for {
+		ts, err := dev.ReadTime()
+		if err != nil {
+			panic(err)
+		}
+		println("tick-tock, it's: " + ts.String())
+		time.Sleep(2 * time.Second)
+	}
+}

examples/sht4x/main.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"fmt"
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/sht4x"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+	sensor := sht4x.New(machine.I2C0)
+
+	for {
+		temp, humidity, _ := sensor.ReadTemperatureHumidity()
+		t := fmt.Sprintf("%.2f", float32(temp)/1000)
+		h := fmt.Sprintf("%.2f", float32(humidity)/100)
+		println("Temperature: ", t, "°C")
+		println("Humidity:    ", h, "%")
+		time.Sleep(2 * time.Second)
+	}
+}

ft6336/ft6336.go

@@ -8,6 +8,7 @@ import (
 	"machine"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 	"tinygo.org/x/drivers/touch"
 )
 
@@ -98,10 +99,10 @@ func (d *Device) Touched() bool {
 }
 
 func (d *Device) write1Byte(reg, data uint8) {
-	d.bus.WriteRegister(d.Address, reg, []byte{data})
+	legacy.WriteRegister(d.bus, d.Address, reg, []byte{data})
 }
 
 func (d *Device) read8bit(reg uint8) uint8 {
-	d.bus.ReadRegister(d.Address, reg, d.buf[:1])
+	legacy.ReadRegister(d.bus, d.Address, reg, d.buf[:1])
 	return d.buf[0]
 }

gbadisplay/gbadisplay.go

@@ -0,0 +1,85 @@
+// Package gbadisplay implements a simple driver for the GameBoy Advance
+// display.
+package gbadisplay
+
+import (
+	"device/gba"
+	"errors"
+	"image/color"
+	"runtime/volatile"
+	"unsafe"
+
+	"tinygo.org/x/drivers/pixel"
+)
+
+// Image buffer type used by the GameBoy Advance.
+type Image = pixel.Image[pixel.RGB555]
+
+const (
+	displayWidth  = 240
+	displayHeight = 160
+)
+
+var (
+	errOutOfBounds = errors.New("rectangle coordinates outside display area")
+)
+
+type Device struct{}
+
+// New returns a new GameBoy Advance display object.
+func New() Device {
+	return Device{}
+}
+
+var displayFrameBuffer = (*[160 * 240]volatile.Register16)(unsafe.Pointer(uintptr(gba.MEM_VRAM)))
+
+type Config struct {
+	// TODO: add more display modes here.
+}
+
+// Configure the display as a regular 15bpp framebuffer.
+func (d Device) Configure(config Config) {
+	// Use video mode 3 (in BG2, a 16bpp bitmap in VRAM) and Enable BG2.
+	gba.DISP.DISPCNT.Set(gba.DISPCNT_BGMODE_3<<gba.DISPCNT_BGMODE_Pos |
+		gba.DISPCNT_SCREENDISPLAY_BG2_ENABLE<<gba.DISPCNT_SCREENDISPLAY_BG2_Pos)
+}
+
+// Size returns the fixed size of this display.
+func (d Device) Size() (x, y int16) {
+	return displayWidth, displayHeight
+}
+
+// Display is a no-op: the display framebuffer is modified directly.
+func (d Device) Display() error {
+	// Nothing to do here.
+	return nil
+}
+
+// SetPixel changes the pixel at (x, y) to the given color.
+func (d Device) SetPixel(x, y int16, c color.RGBA) {
+	if x < 0 || y < 0 || x >= displayWidth || y > displayHeight {
+		// Out of bounds, so ignore.
+		return
+	}
+	val := pixel.NewColor[pixel.RGB555](c.R, c.G, c.B)
+	displayFrameBuffer[(int(y))*240+int(x)].Set(uint16(val))
+}
+
+// DrawBitmap updates the rectangle at (x, y) to the image stored in buf.
+func (d Device) DrawBitmap(x, y int16, buf Image) error {
+	width, height := buf.Size()
+	if x < 0 || y < 0 || int(x)+width > displayWidth || int(y)+height > displayHeight {
+		return errOutOfBounds
+	}
+
+	// TODO: try to do a 4-byte memcpy if possible. That should significantly
+	// speed up the copying of this image.
+	for bufY := 0; bufY < int(height); bufY++ {
+		for bufX := 0; bufX < int(width); bufX++ {
+			val := buf.Get(bufX, bufY)
+			displayFrameBuffer[(int(y)+bufY)*240+int(x)+bufX].Set(uint16(val))
+		}
+	}
+
+	return nil
+}

go.mod

@@ -1,12 +1,20 @@
 module tinygo.org/x/drivers
 
-go 1.15
+go 1.18
 
 require (
 	github.com/eclipse/paho.mqtt.golang v1.2.0
 	github.com/frankban/quicktest v1.10.2
 	github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510
-	golang.org/x/net v0.0.0-20210614182718-04defd469f4e
+	golang.org/x/net v0.7.0
 	tinygo.org/x/tinyfont v0.3.0
 	tinygo.org/x/tinyterm v0.1.0
 )
+
+require (
+	github.com/google/go-cmp v0.5.2 // indirect
+	github.com/kr/pretty v0.2.1 // indirect
+	github.com/kr/text v0.1.0 // indirect
+	golang.org/x/text v0.7.0 // indirect
+	golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 // indirect
+)

go.sum

@@ -7,32 +7,22 @@ github.com/google/go-cmp v0.5.2 h1:X2ev0eStA3AbceY54o37/0PQ/UWqKEiiO2dKL5OPaFM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510 h1:El6M4kTTCOh6aBiKaUGG7oYTSPP8MxqL4YI3kZKwcP4=
 github.com/google/shlex v0.0.0-20191202100458-e7afc7fbc510/go.mod h1:pupxD2MaaD3pAXIBCelhxNneeOaAeabZDe5s4K6zSpQ=
-github.com/hajimehoshi/go-jisx0208 v1.0.0/go.mod h1:yYxEStHL7lt9uL+AbdWgW9gBumwieDoZCiB1f/0X0as=
 github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/sago35/go-bdf v0.0.0-20200313142241-6c17821c91c4/go.mod h1:rOebXGuMLsXhZAC6mF/TjxONsm45498ZyzVhel++6KM=
 github.com/valyala/fastjson v1.6.3/go.mod h1:CLCAqky6SMuOcxStkYQvblddUtoRxhYMGLrsQns1aXY=
-golang.org/x/image v0.0.0-20210628002857-a66eb6448b8d/go.mod h1:023OzeP/+EPmXeapQh35lcL3II3LrY8Ic+EFFKVhULM=
-golang.org/x/net v0.0.0-20210614182718-04defd469f4e h1:XpT3nA5TvE525Ne3hInMh6+GETgn27Zfm9dxsThnX2Q=
-golang.org/x/net v0.0.0-20210614182718-04defd469f4e/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/text v0.3.6 h1:aRYxNxv6iGQlyVaZmk6ZgYEDa+Jg18DxebPSrd6bg1M=
-golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/net v0.7.0 h1:rJrUqqhjsgNp7KqAIc25s9pZnjU7TUcSY7HcVZjdn1g=
+golang.org/x/net v0.7.0/go.mod h1:2Tu9+aMcznHK/AK1HMvgo6xiTLG5rD5rZLDS+rp2Bjs=
+golang.org/x/text v0.7.0 h1:4BRB4x83lYWy72KwLD/qYDuTu7q9PjSagHvijDw7cLo=
+golang.org/x/text v0.7.0/go.mod h1:mrYo+phRRbMaCq/xk9113O4dZlRixOauAjOtrjsXDZ8=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 tinygo.org/x/drivers v0.14.0/go.mod h1:uT2svMq3EpBZpKkGO+NQHjxjGf1f42ra4OnMMwQL2aI=
 tinygo.org/x/drivers v0.15.1/go.mod h1:uT2svMq3EpBZpKkGO+NQHjxjGf1f42ra4OnMMwQL2aI=
-tinygo.org/x/drivers v0.16.0/go.mod h1:uT2svMq3EpBZpKkGO+NQHjxjGf1f42ra4OnMMwQL2aI=
-tinygo.org/x/drivers v0.19.0/go.mod h1:uJD/l1qWzxzLx+vcxaW0eY464N5RAgFi1zTVzASFdqI=
 tinygo.org/x/tinyfont v0.2.1/go.mod h1:eLqnYSrFRjt5STxWaMeOWJTzrKhXqpWw7nU3bPfKOAM=
 tinygo.org/x/tinyfont v0.3.0 h1:HIRLQoI3oc+2CMhPcfv+Ig88EcTImE/5npjqOnMD4lM=
 tinygo.org/x/tinyfont v0.3.0/go.mod h1:+TV5q0KpwSGRWnN+ITijsIhrWYJkoUCp9MYELjKpAXk=
-tinygo.org/x/tinyfs v0.1.0/go.mod h1:ysc8Y92iHfhTXeyEM9+c7zviUQ4fN9UCFgSOFfMWv20=
 tinygo.org/x/tinyterm v0.1.0 h1:80i+j+KWoxCFa/Xfp6pWbh79x+8zUdMXC1vaKj2QhkY=
 tinygo.org/x/tinyterm v0.1.0/go.mod h1:/DDhNnGwNF2/tNgHywvyZuCGnbH3ov49Z/6e8LPLRR4=

hts221/hts221.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a HTS221 device.
@@ -32,7 +33,7 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(d.Address, HTS221_WHO_AM_I_REG, data)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_WHO_AM_I_REG, data)
 	return data[0] == 0xBC
 }
 
@@ -42,7 +43,7 @@ func (d *Device) Power(status bool) {
 	if status {
 		data[0] = 0x84
 	}
-	d.bus.WriteRegister(d.Address, HTS221_CTRL1_REG, data)
+	legacy.WriteRegister(d.bus, d.Address, HTS221_CTRL1_REG, data)
 }
 
 // ReadHumidity returns the relative humidity in percent * 100.
@@ -55,8 +56,8 @@ func (d *Device) ReadHumidity() (humidity int32, err error) {
 
 	// read data and calibrate
 	data := []byte{0, 0}
-	d.bus.ReadRegister(d.Address, HTS221_HUMID_OUT_REG, data[:1])
-	d.bus.ReadRegister(d.Address, HTS221_HUMID_OUT_REG+1, data[1:])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_HUMID_OUT_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_HUMID_OUT_REG+1, data[1:])
 	hValue := readInt(data[1], data[0])
 	hValueCalib := float32(hValue)*d.humiditySlope + d.humidityZero
 
@@ -73,8 +74,8 @@ func (d *Device) ReadTemperature() (temperature int32, err error) {
 
 	// read data and calibrate
 	data := []byte{0, 0}
-	d.bus.ReadRegister(d.Address, HTS221_TEMP_OUT_REG, data[:1])
-	d.bus.ReadRegister(d.Address, HTS221_TEMP_OUT_REG+1, data[1:])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_TEMP_OUT_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_TEMP_OUT_REG+1, data[1:])
 	tValue := readInt(data[1], data[0])
 	tValueCalib := float32(tValue)*d.temperatureSlope + d.temperatureZero
 
@@ -91,7 +92,7 @@ func (d *Device) Resolution(h uint8, t uint8) {
 	if t > 7 {
 		t = 3 // default
 	}
-	d.bus.WriteRegister(d.Address, HTS221_AV_CONF_REG, []byte{h<<3 | t})
+	legacy.WriteRegister(d.bus, d.Address, HTS221_AV_CONF_REG, []byte{h<<3 | t})
 }
 
 // private functions
@@ -104,19 +105,19 @@ func (d *Device) calibration() {
 	h0t0Out, h1t0Out := []byte{0, 0}, []byte{0, 0}
 	t0Out, t1Out := []byte{0, 0}, []byte{0, 0}
 
-	d.bus.ReadRegister(d.Address, HTS221_H0_rH_x2_REG, h0rH)
-	d.bus.ReadRegister(d.Address, HTS221_H1_rH_x2_REG, h1rH)
-	d.bus.ReadRegister(d.Address, HTS221_T0_degC_x8_REG, t0degC)
-	d.bus.ReadRegister(d.Address, HTS221_T1_degC_x8_REG, t1degC)
-	d.bus.ReadRegister(d.Address, HTS221_T1_T0_MSB_REG, t1t0msb)
-	d.bus.ReadRegister(d.Address, HTS221_H0_T0_OUT_REG, h0t0Out[:1])
-	d.bus.ReadRegister(d.Address, HTS221_H0_T0_OUT_REG+1, h0t0Out[1:])
-	d.bus.ReadRegister(d.Address, HTS221_H1_T0_OUT_REG, h1t0Out[:1])
-	d.bus.ReadRegister(d.Address, HTS221_H1_T0_OUT_REG+1, h1t0Out[1:])
-	d.bus.ReadRegister(d.Address, HTS221_T0_OUT_REG, t0Out[:1])
-	d.bus.ReadRegister(d.Address, HTS221_T0_OUT_REG+1, t0Out[1:])
-	d.bus.ReadRegister(d.Address, HTS221_T1_OUT_REG, t1Out[:1])
-	d.bus.ReadRegister(d.Address, HTS221_T1_OUT_REG+1, t1Out[1:])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_H0_rH_x2_REG, h0rH)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_H1_rH_x2_REG, h1rH)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T0_degC_x8_REG, t0degC)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T1_degC_x8_REG, t1degC)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T1_T0_MSB_REG, t1t0msb)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_H0_T0_OUT_REG, h0t0Out[:1])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_H0_T0_OUT_REG+1, h0t0Out[1:])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_H1_T0_OUT_REG, h1t0Out[:1])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_H1_T0_OUT_REG+1, h1t0Out[1:])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T0_OUT_REG, t0Out[:1])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T0_OUT_REG+1, t0Out[1:])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T1_OUT_REG, t1Out[:1])
+	legacy.ReadRegister(d.bus, d.Address, HTS221_T1_OUT_REG+1, t1Out[1:])
 
 	h0rH_v := float32(h0rH[0]) / 2.0
 	h1rH_v := float32(h1rH[0]) / 2.0
@@ -138,7 +139,7 @@ func (d *Device) waitForOneShot(filter uint8) error {
 	data := []byte{0}
 
 	// check if the device is on
-	d.bus.ReadRegister(d.Address, HTS221_CTRL1_REG, data)
+	legacy.ReadRegister(d.bus, d.Address, HTS221_CTRL1_REG, data)
 	if data[0]&0x80 == 0 {
 		return errors.New("device is off, unable to query")
 	}
@@ -146,19 +147,19 @@ func (d *Device) waitForOneShot(filter uint8) error {
 	// wait until one shot (one conversion) is ready to go
 	data[0] = 1
 	for {
-		d.bus.ReadRegister(d.Address, HTS221_CTRL2_REG, data)
+		legacy.ReadRegister(d.bus, d.Address, HTS221_CTRL2_REG, data)
 		if data[0]&0x01 == 0 {
 			break
 		}
 	}
 
 	// trigger one shot
-	d.bus.WriteRegister(d.Address, HTS221_CTRL2_REG, []byte{0x01})
+	legacy.WriteRegister(d.bus, d.Address, HTS221_CTRL2_REG, []byte{0x01})
 
 	// wait until conversion completed
 	data[0] = 0
 	for {
-		d.bus.ReadRegister(d.Address, HTS221_STATUS_REG, data)
+		legacy.ReadRegister(d.bus, d.Address, HTS221_STATUS_REG, data)
 		if data[0]&filter == filter {
 			break
 		}

i2c.go

@@ -3,7 +3,15 @@ package drivers
 // I2C represents an I2C bus. It is notably implemented by the
 // machine.I2C type.
 type I2C interface {
-	ReadRegister(addr uint8, r uint8, buf []byte) error
-	WriteRegister(addr uint8, r uint8, buf []byte) error
+	// Tx performs a [I²C] transaction with address addr.
+	// Most I2C peripherals have some sort of register mapping scheme to allow
+	// users to interact with them:
+	//
+	//  bus.Tx(addr, []byte{reg}, buf) // Reads register reg into buf.
+	//  bus.Tx(addr, append([]byte{reg}, buf...), nil) // Writes buf into register reg.
+	//
+	// The semantics of most I2C transactions require that the w write buffer be non-empty.
+	//
+	// [I²C]: https://en.wikipedia.org/wiki/I%C2%B2C
 	Tx(addr uint16, w, r []byte) error
 }

ili9341/ili9341.go

@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/pixel"
 )
 
 type Config struct {
@@ -31,6 +32,9 @@ type Device struct {
 	rd  machine.Pin
 }
 
+// Image buffer type used in the ili9341.
+type Image = pixel.Image[pixel.RGB565BE]
+
 var cmdBuf [6]byte
 
 var initCmd = []byte{
@@ -173,6 +177,8 @@ func (d *Device) EnableTEOutput(on bool) {
 }
 
 // DrawRGBBitmap copies an RGB bitmap to the internal buffer at given coordinates
+//
+// Deprecated: use DrawBitmap instead.
 func (d *Device) DrawRGBBitmap(x, y int16, data []uint16, w, h int16) error {
 	k, i := d.Size()
 	if x < 0 || y < 0 || w <= 0 || h <= 0 ||
@@ -187,6 +193,8 @@ func (d *Device) DrawRGBBitmap(x, y int16, data []uint16, w, h int16) error {
 }
 
 // DrawRGBBitmap8 copies an RGB bitmap to the internal buffer at given coordinates
+//
+// Deprecated: use DrawBitmap instead.
 func (d *Device) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
 	k, i := d.Size()
 	if x < 0 || y < 0 || w <= 0 || h <= 0 ||
@@ -200,6 +208,13 @@ func (d *Device) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
 	return nil
 }
 
+// DrawBitmap copies the bitmap to the internal buffer on the screen at the
+// given coordinates. It returns once the image data has been sent completely.
+func (d *Device) DrawBitmap(x, y int16, bitmap Image) error {
+	width, height := bitmap.Size()
+	return d.DrawRGBBitmap8(x, y, bitmap.RawBuffer(), int16(width), int16(height))
+}
+
 // FillRectangle fills a rectangle at given coordinates with a color
 func (d *Device) FillRectangle(x, y, width, height int16, c color.RGBA) error {
 	k, i := d.Size()
@@ -320,10 +335,16 @@ func (d *Device) SetRotation(rotation drivers.Rotation) error {
 // SetScrollArea sets an area to scroll with fixed top/bottom or left/right parts of the display
 // Rotation affects scroll direction
 func (d *Device) SetScrollArea(topFixedArea, bottomFixedArea int16) {
+	if d.height < 320 {
+		// The screen doesn't use the full 320 pixel height.
+		// Enlarge the bottom fixed area to fill the 320 pixel height, so that
+		// bottomFixedArea starts from the visible bottom of the screen.
+		bottomFixedArea += 320 - d.height
+	}
 	cmdBuf[0] = uint8(topFixedArea >> 8)
 	cmdBuf[1] = uint8(topFixedArea)
-	cmdBuf[2] = uint8(d.height - topFixedArea - bottomFixedArea>>8)
-	cmdBuf[3] = uint8(d.height - topFixedArea - bottomFixedArea)
+	cmdBuf[2] = uint8((320 - topFixedArea - bottomFixedArea) >> 8)
+	cmdBuf[3] = uint8(320 - topFixedArea - bottomFixedArea)
 	cmdBuf[4] = uint8(bottomFixedArea >> 8)
 	cmdBuf[5] = uint8(bottomFixedArea)
 	d.sendCommand(VSCRDEF, cmdBuf[:6])

ina260/ina260.go

@@ -1,6 +1,9 @@
 package ina260
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device wraps an I2C connection to an INA260 device.
 type Device struct {
@@ -97,7 +100,7 @@ func (d *Device) Power() int32 {
 // Read a register
 func (d *Device) ReadRegister(reg uint8) uint16 {
 	data := []byte{0, 0}
-	d.bus.ReadRegister(uint8(d.Address), reg, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), reg, data)
 	return (uint16(data[0]) << 8) | uint16(data[1])
 }
 
@@ -107,5 +110,5 @@ func (d *Device) WriteRegister(reg uint8, v uint16) {
 	data[0] = byte(v >> 8)
 	data[1] = byte(v & 0xff)
 
-	d.bus.WriteRegister(uint8(d.Address), reg, data)
+	legacy.WriteRegister(d.bus, uint8(d.Address), reg, data)
 }

internal/legacy/i2clegacy.go

@@ -0,0 +1,14 @@
+package legacy
+
+import "tinygo.org/x/drivers"
+
+func ReadRegister(bus drivers.I2C, addr uint8, reg uint8, data []byte) error {
+	return bus.Tx(uint16(addr), []byte{reg}, data)
+}
+
+func WriteRegister(bus drivers.I2C, addr uint8, reg uint8, data []byte) error {
+	buf := make([]uint8, len(data)+1)
+	buf[0] = reg
+	copy(buf[1:], data)
+	return bus.Tx(uint16(addr), buf, nil)
+}

is31fl3731/is31fl3731.go

@@ -20,6 +20,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device implements TinyGo driver for Lumissil IS31FL3731 matrix LED driver
@@ -92,7 +93,7 @@ func (d *Device) Configure() (err error) {
 func (d *Device) selectCommand(command uint8) (err error) {
 	if command != d.selectedCommand {
 		d.selectedCommand = command
-		return d.bus.WriteRegister(d.Address, COMMAND, []byte{command})
+		return legacy.WriteRegister(d.bus, d.Address, COMMAND, []byte{command})
 	}
 
 	return nil
@@ -105,7 +106,7 @@ func (d *Device) writeFunctionRegister(operation uint8, data []byte) (err error)
 		return err
 	}
 
-	return d.bus.WriteRegister(d.Address, operation, data)
+	return legacy.WriteRegister(d.bus, d.Address, operation, data)
 }
 
 // enableLEDs enables only LEDs that are soldered on the set board. Enabled
@@ -119,7 +120,7 @@ func (d *Device) enableLEDs() (err error) {
 
 		// Enable every LED (16 columns x 9 rows)
 		for i := uint8(0); i < 16; i++ {
-			err = d.bus.WriteRegister(d.Address, i, []byte{0xFF})
+			err = legacy.WriteRegister(d.bus, d.Address, i, []byte{0xFF})
 			if err != nil {
 				return err
 			}
@@ -136,7 +137,7 @@ func (d *Device) setPixelPWD(frame, n, value uint8) (err error) {
 		return err
 	}
 
-	return d.bus.WriteRegister(d.Address, LED_PWM_OFFSET+n, []byte{value})
+	return legacy.WriteRegister(d.bus, d.Address, LED_PWM_OFFSET+n, []byte{value})
 }
 
 // SetActiveFrame sets frame to display with LEDs
@@ -165,7 +166,7 @@ func (d *Device) Fill(frame, value uint8) (err error) {
 	}
 
 	for i := uint8(0); i < 6; i++ {
-		err = d.bus.WriteRegister(d.Address, LED_PWM_OFFSET+i*24, data)
+		err = legacy.WriteRegister(d.bus, d.Address, LED_PWM_OFFSET+i*24, data)
 		if err != nil {
 			return err
 		}

is31fl3731/is31fl3731_acw15x7.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // DeviceAdafruitCharlieWing15x7 implements TinyGo driver for Lumissil
@@ -47,20 +48,20 @@ func (d *DeviceAdafruitCharlieWing15x7) enableLEDs() (err error) {
 
 		// Enable left half
 		for i := uint8(0); i < 16; i += 2 {
-			err = d.bus.WriteRegister(d.Address, i, []byte{0b11111110})
+			err = legacy.WriteRegister(d.bus, d.Address, i, []byte{0b11111110})
 			if err != nil {
 				return err
 			}
 		}
 		// Enable right half
 		for i := uint8(3); i < 16; i += 2 {
-			err = d.bus.WriteRegister(d.Address, i, []byte{0b01111111})
+			err = legacy.WriteRegister(d.bus, d.Address, i, []byte{0b01111111})
 			if err != nil {
 				return err
 			}
 		}
 		// Disable invisible column on the right side
-		err = d.bus.WriteRegister(d.Address, 1, []byte{0b00000000})
+		err = legacy.WriteRegister(d.bus, d.Address, 1, []byte{0b00000000})
 		if err != nil {
 			return err
 		}

l3gd20/i2c.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 const (
@@ -87,15 +88,15 @@ func (d *DevI2C) Configure(cfg Config) error {
 }
 
 func (d *DevI2C) Update() error {
-	err := d.bus.ReadRegister(d.addr, OUT_X_L, d.databuf[:2])
+	err := legacy.ReadRegister(d.bus, d.addr, OUT_X_L, d.databuf[:2])
 	if err != nil {
 		return err
 	}
-	err = d.bus.ReadRegister(d.addr, OUT_Y_L, d.databuf[2:4])
+	err = legacy.ReadRegister(d.bus, d.addr, OUT_Y_L, d.databuf[2:4])
 	if err != nil {
 		return err
 	}
-	err = d.bus.ReadRegister(d.addr, OUT_Z_L, d.databuf[4:6])
+	err = legacy.ReadRegister(d.bus, d.addr, OUT_Z_L, d.databuf[4:6])
 	if err != nil {
 		return err
 	}
@@ -131,11 +132,11 @@ func (d *DevI2C) AngularVelocity() (x, y, z int32) {
 // func (d DevI2C) Update(measurement)
 
 func (d DevI2C) read8(reg uint8) (byte, error) {
-	err := d.bus.ReadRegister(d.addr, reg, d.buf[:1])
+	err := legacy.ReadRegister(d.bus, d.addr, reg, d.buf[:1])
 	return d.buf[0], err
 }
 
 func (d DevI2C) write8(reg uint8, val byte) error {
 	d.buf[0] = val
-	return d.bus.WriteRegister(d.addr, reg, d.buf[:1])
+	return legacy.WriteRegister(d.bus, d.addr, reg, d.buf[:1])
 }

lis2mdl/lis2mdl.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a LIS2MDL device.
@@ -38,7 +39,7 @@ func New(bus drivers.I2C) Device {
 // Connected returns whether LIS2MDL sensor has been found.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x40
 }
 
@@ -66,25 +67,25 @@ func (d *Device) Configure(cfg Configuration) {
 
 	// reset
 	cmd[0] = byte(1 << 5)
-	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
+	legacy.WriteRegister(d.bus, uint8(d.Address), CFG_REG_A, cmd)
 	time.Sleep(100 * time.Millisecond)
 
 	// reboot
 	cmd[0] = byte(1 << 6)
-	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
+	legacy.WriteRegister(d.bus, uint8(d.Address), CFG_REG_A, cmd)
 	time.Sleep(100 * time.Millisecond)
 
 	// bdu
 	cmd[0] = byte(1 << 4)
-	d.bus.WriteRegister(uint8(d.Address), CFG_REG_C, cmd)
+	legacy.WriteRegister(d.bus, uint8(d.Address), CFG_REG_C, cmd)
 
 	// Temperature compensation is on for magnetic sensor (0x80)
 	cmd[0] = byte(0x80)
-	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
+	legacy.WriteRegister(d.bus, uint8(d.Address), CFG_REG_A, cmd)
 
 	// speed
 	cmd[0] = byte(0x80 | d.DataRate)
-	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
+	legacy.WriteRegister(d.bus, uint8(d.Address), CFG_REG_A, cmd)
 }
 
 // ReadMagneticField reads the current magnetic field from the device and returns
@@ -93,11 +94,11 @@ func (d *Device) ReadMagneticField() (x int32, y int32, z int32) {
 	// turn back on read mode, even though it is supposed to be continuous?
 	cmd := []byte{0}
 	cmd[0] = byte(0x80 | d.PowerMode<<4 | d.DataRate<<2 | d.SystemMode)
-	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
+	legacy.WriteRegister(d.bus, uint8(d.Address), CFG_REG_A, cmd)
 	time.Sleep(10 * time.Millisecond)
 
 	data := make([]byte, 6)
-	d.bus.ReadRegister(uint8(d.Address), OUTX_L_REG, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_REG, data)
 
 	x = int32(int16((uint16(data[0]) << 8) | uint16(data[1])))
 	y = int32(int16((uint16(data[2]) << 8) | uint16(data[3])))

lis3dh/lis3dh.go

@@ -3,7 +3,10 @@
 // Datasheet: https://www.st.com/resource/en/datasheet/lis3dh.pdf
 package lis3dh // import "tinygo.org/x/drivers/lis3dh"
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device wraps an I2C connection to a LIS3DH device.
 type Device struct {
@@ -22,13 +25,13 @@ func New(bus drivers.I2C) Device {
 // Configure sets up the device for communication
 func (d *Device) Configure() {
 	// enable all axes, normal mode
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL1, []byte{0x07})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL1, []byte{0x07})
 
 	// 400Hz rate
 	d.SetDataRate(DATARATE_400_HZ)
 
 	// High res & BDU enabled
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL4, []byte{0x88})
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL4, []byte{0x88})
 
 	// get current range
 	d.r = d.ReadRange()
@@ -38,7 +41,7 @@ func (d *Device) Configure() {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	err := d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	if err != nil {
 		return false
 	}
@@ -48,27 +51,27 @@ func (d *Device) Connected() bool {
 // SetDataRate sets the speed of data collected by the LIS3DH.
 func (d *Device) SetDataRate(rate DataRate) {
 	ctl1 := []byte{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CTRL1, ctl1)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CTRL1, ctl1)
 	if err != nil {
 		println(err.Error())
 	}
 	// mask off bits
 	ctl1[0] &^= 0xf0
 	ctl1[0] |= (byte(rate) << 4)
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL1, ctl1)
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL1, ctl1)
 }
 
 // SetRange sets the G range for LIS3DH.
 func (d *Device) SetRange(r Range) {
 	ctl := []byte{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CTRL4, ctl)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CTRL4, ctl)
 	if err != nil {
 		println(err.Error())
 	}
 	// mask off bits
 	ctl[0] &^= 0x30
 	ctl[0] |= (byte(r) << 4)
-	d.bus.WriteRegister(uint8(d.Address), REG_CTRL4, ctl)
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_CTRL4, ctl)
 
 	// store the new range
 	d.r = r
@@ -77,7 +80,7 @@ func (d *Device) SetRange(r Range) {
 // ReadRange returns the current G range for LIS3DH.
 func (d *Device) ReadRange() (r Range) {
 	ctl := []byte{0}
-	err := d.bus.ReadRegister(uint8(d.Address), REG_CTRL4, ctl)
+	err := legacy.ReadRegister(d.bus, uint8(d.Address), REG_CTRL4, ctl)
 	if err != nil {
 		println(err.Error())
 	}
@@ -111,7 +114,7 @@ func (d *Device) ReadAcceleration() (int32, int32, int32, error) {
 
 // ReadRawAcceleration returns the raw x, y and z axis from the LIS3DH
 func (d *Device) ReadRawAcceleration() (x int16, y int16, z int16) {
-	d.bus.WriteRegister(uint8(d.Address), REG_OUT_X_L|0x80, nil)
+	legacy.WriteRegister(d.bus, uint8(d.Address), REG_OUT_X_L|0x80, nil)
 
 	data := []byte{0, 0, 0, 0, 0, 0}
 	d.bus.Tx(d.Address, nil, data)

lora/config.go

@@ -80,6 +80,9 @@ const (
 const (
 	MHz_868_1 = 868100000
 	MHz_868_5 = 868500000
+	MHz_902_3 = 902300000
+	Mhz_903_0 = 903000000
+	MHZ_915_0 = 915000000
 	MHz_916_8 = 916800000
 	MHz_923_3 = 923300000
 )

lora/lorawan/adaptor.go

@@ -30,11 +30,11 @@ const (
 var (
 	ActiveRadio    lora.Radio
 	Retries        = 15
-	regionSettings region.RegionSettings
+	regionSettings region.Settings
 )
 
 // UseRegionSettings sets current Lorawan Regional parameters
-func UseRegionSettings(rs region.RegionSettings) {
+func UseRegionSettings(rs region.Settings) {
 	regionSettings = rs
 }
 
@@ -52,13 +52,13 @@ func SetPublicNetwork(enabled bool) {
 }
 
 // ApplyChannelConfig sets current Lora modulation according to current regional settings
-func applyChannelConfig(ch *region.Channel) {
-	ActiveRadio.SetFrequency(ch.Frequency)
-	ActiveRadio.SetBandwidth(ch.Bandwidth)
-	ActiveRadio.SetCodingRate(ch.CodingRate)
-	ActiveRadio.SetSpreadingFactor(ch.SpreadingFactor)
-	ActiveRadio.SetPreambleLength(ch.PreambleLength)
-	ActiveRadio.SetTxPower(ch.TxPowerDBm)
+func applyChannelConfig(ch region.Channel) {
+	ActiveRadio.SetFrequency(ch.Frequency())
+	ActiveRadio.SetBandwidth(ch.Bandwidth())
+	ActiveRadio.SetCodingRate(ch.CodingRate())
+	ActiveRadio.SetSpreadingFactor(ch.SpreadingFactor())
+	ActiveRadio.SetPreambleLength(ch.PreambleLength())
+	ActiveRadio.SetTxPower(ch.TxPowerDBm())
 	// Lorawan defaults to explicit headers
 	ActiveRadio.SetHeaderType(lora.HeaderExplicit)
 	ActiveRadio.SetCrc(true)
@@ -84,24 +84,30 @@ func Join(otaa *Otaa, session *Session) error {
 		return err
 	}
 
-	// Prepare radio for Join Tx
-	applyChannelConfig(regionSettings.JoinRequestChannel())
-	ActiveRadio.SetIqMode(lora.IQStandard)
-	ActiveRadio.Tx(payload, LORA_TX_TIMEOUT)
-	if err != nil {
-		return err
-	}
+	for {
+		joinRequestChannel := regionSettings.JoinRequestChannel()
+		joinAcceptChannel := regionSettings.JoinAcceptChannel()
 
-	// Wait for JoinAccept
-	applyChannelConfig(regionSettings.JoinAcceptChannel())
-	ActiveRadio.SetIqMode(lora.IQInverted)
-	resp, err = ActiveRadio.Rx(LORA_RX_TIMEOUT)
-	if err != nil {
-		return err
-	}
+		// Prepare radio for Join Tx
+		applyChannelConfig(joinRequestChannel)
+		ActiveRadio.SetIqMode(lora.IQStandard)
+		ActiveRadio.Tx(payload, LORA_TX_TIMEOUT)
+		if err != nil {
+			return err
+		}
 
-	if resp == nil {
-		return ErrNoJoinAcceptReceived
+		// Wait for JoinAccept
+		if joinAcceptChannel.Frequency() != 0 {
+			applyChannelConfig(joinAcceptChannel)
+		}
+		ActiveRadio.SetIqMode(lora.IQInverted)
+		resp, err = ActiveRadio.Rx(LORA_RX_TIMEOUT)
+		if err == nil && resp != nil {
+			break
+		}
+		if !joinAcceptChannel.Next() {
+			return ErrNoJoinAcceptReceived
+		}
 	}
 
 	err = otaa.DecodeJoinAccept(resp, session)

lora/lorawan/region/au915.go

@@ -7,43 +7,41 @@ const (
 	AU915_DEFAULT_TX_POWER_DBM = 20
 )
 
-type RegionSettingsAU915 struct {
-	joinRequestChannel *Channel
-	joinAcceptChannel  *Channel
-	uplinkChannel      *Channel
+type ChannelAU struct {
+	channel
 }
 
-func AU915() *RegionSettingsAU915 {
-	return &RegionSettingsAU915{
-		joinRequestChannel: &Channel{lora.MHz_916_8,
+func (c *ChannelAU) Next() bool {
+	return false
+}
+
+type SettingsAU915 struct {
+	settings
+}
+
+func AU915() *SettingsAU915 {
+	return &SettingsAU915{settings: settings{
+		joinRequestChannel: &ChannelAU{channel: channel{lora.MHz_916_8,
 			lora.Bandwidth_125_0,
 			lora.SpreadingFactor9,
 			lora.CodingRate4_5,
 			AU915_DEFAULT_PREAMBLE_LEN,
-			AU915_DEFAULT_TX_POWER_DBM},
-		joinAcceptChannel: &Channel{lora.MHz_923_3,
+			AU915_DEFAULT_TX_POWER_DBM}},
+		joinAcceptChannel: &ChannelAU{channel: channel{lora.MHz_923_3,
 			lora.Bandwidth_500_0,
 			lora.SpreadingFactor9,
 			lora.CodingRate4_5,
 			AU915_DEFAULT_PREAMBLE_LEN,
-			AU915_DEFAULT_TX_POWER_DBM},
-		uplinkChannel: &Channel{lora.MHz_916_8,
+			AU915_DEFAULT_TX_POWER_DBM}},
+		uplinkChannel: &ChannelAU{channel: channel{lora.MHz_916_8,
 			lora.Bandwidth_125_0,
 			lora.SpreadingFactor9,
 			lora.CodingRate4_5,
 			AU915_DEFAULT_PREAMBLE_LEN,
-			AU915_DEFAULT_TX_POWER_DBM},
-	}
+			AU915_DEFAULT_TX_POWER_DBM}},
+	}}
 }
 
-func (r *RegionSettingsAU915) JoinRequestChannel() *Channel {
-	return r.joinRequestChannel
-}
-
-func (r *RegionSettingsAU915) JoinAcceptChannel() *Channel {
-	return r.joinAcceptChannel
-}
-
-func (r *RegionSettingsAU915) UplinkChannel() *Channel {
-	return r.uplinkChannel
+func Next(c *ChannelAU) bool {
+	return false
 }

lora/lorawan/region/channel.go

@@ -0,0 +1,42 @@
+package region
+
+type Channel interface {
+	Next() bool
+	Frequency() uint32
+	Bandwidth() uint8
+	SpreadingFactor() uint8
+	CodingRate() uint8
+	PreambleLength() uint16
+	TxPowerDBm() int8
+	SetFrequency(v uint32)
+	SetBandwidth(v uint8)
+	SetSpreadingFactor(v uint8)
+	SetCodingRate(v uint8)
+	SetPreambleLength(v uint16)
+	SetTxPowerDBm(v int8)
+}
+
+type channel struct {
+	frequency       uint32
+	bandwidth       uint8
+	spreadingFactor uint8
+	codingRate      uint8
+	preambleLength  uint16
+	txPowerDBm      int8
+}
+
+// Getter functions
+func (c *channel) Frequency() uint32      { return c.frequency }
+func (c *channel) Bandwidth() uint8       { return c.bandwidth }
+func (c *channel) SpreadingFactor() uint8 { return c.spreadingFactor }
+func (c *channel) CodingRate() uint8      { return c.codingRate }
+func (c *channel) PreambleLength() uint16 { return c.preambleLength }
+func (c *channel) TxPowerDBm() int8       { return c.txPowerDBm }
+
+// Set functions
+func (c *channel) SetFrequency(v uint32)      { c.frequency = v }
+func (c *channel) SetBandwidth(v uint8)       { c.bandwidth = v }
+func (c *channel) SetSpreadingFactor(v uint8) { c.spreadingFactor = v }
+func (c *channel) SetCodingRate(v uint8)      { c.codingRate = v }
+func (c *channel) SetPreambleLength(v uint16) { c.preambleLength = v }
+func (c *channel) SetTxPowerDBm(v int8)       { c.txPowerDBm = v }

lora/lorawan/region/eu868.go

@@ -7,43 +7,37 @@ const (
 	EU868_DEFAULT_TX_POWER_DBM = 20
 )
 
-type RegionSettingsEU868 struct {
-	joinRequestChannel *Channel
-	joinAcceptChannel  *Channel
-	uplinkChannel      *Channel
+type ChannelEU struct {
+	channel
 }
 
-func EU868() *RegionSettingsEU868 {
-	return &RegionSettingsEU868{
-		joinRequestChannel: &Channel{lora.MHz_868_1,
+func (c *ChannelEU) Next() bool {
+	return false
+}
+
+type SettingsEU868 struct {
+	settings
+}
+
+func EU868() *SettingsEU868 {
+	return &SettingsEU868{settings: settings{
+		joinRequestChannel: &ChannelEU{channel: channel{lora.MHz_868_1,
 			lora.Bandwidth_125_0,
 			lora.SpreadingFactor9,
 			lora.CodingRate4_7,
 			EU868_DEFAULT_PREAMBLE_LEN,
-			EU868_DEFAULT_TX_POWER_DBM},
-		joinAcceptChannel: &Channel{lora.MHz_868_1,
+			EU868_DEFAULT_TX_POWER_DBM}},
+		joinAcceptChannel: &ChannelEU{channel: channel{lora.MHz_868_1,
 			lora.Bandwidth_125_0,
 			lora.SpreadingFactor9,
 			lora.CodingRate4_7,
 			EU868_DEFAULT_PREAMBLE_LEN,
-			EU868_DEFAULT_TX_POWER_DBM},
-		uplinkChannel: &Channel{lora.MHz_868_1,
+			EU868_DEFAULT_TX_POWER_DBM}},
+		uplinkChannel: &ChannelEU{channel: channel{lora.MHz_868_1,
 			lora.Bandwidth_125_0,
 			lora.SpreadingFactor9,
 			lora.CodingRate4_7,
 			EU868_DEFAULT_PREAMBLE_LEN,
-			EU868_DEFAULT_TX_POWER_DBM},
-	}
-}
-
-func (r *RegionSettingsEU868) JoinRequestChannel() *Channel {
-	return r.joinRequestChannel
-}
-
-func (r *RegionSettingsEU868) JoinAcceptChannel() *Channel {
-	return r.joinAcceptChannel
-}
-
-func (r *RegionSettingsEU868) UplinkChannel() *Channel {
-	return r.uplinkChannel
+			EU868_DEFAULT_TX_POWER_DBM}},
+	}}
 }

lora/lorawan/region/regionset.go

@@ -1,16 +0,0 @@
-package region
-
-type Channel struct {
-	Frequency       uint32
-	Bandwidth       uint8
-	SpreadingFactor uint8
-	CodingRate      uint8
-	PreambleLength  uint16
-	TxPowerDBm      int8
-}
-
-type RegionSettings interface {
-	JoinRequestChannel() *Channel
-	JoinAcceptChannel() *Channel
-	UplinkChannel() *Channel
-}

lora/lorawan/region/settings.go

@@ -0,0 +1,25 @@
+package region
+
+type Settings interface {
+	JoinRequestChannel() Channel
+	JoinAcceptChannel() Channel
+	UplinkChannel() Channel
+}
+
+type settings struct {
+	joinRequestChannel Channel
+	joinAcceptChannel  Channel
+	uplinkChannel      Channel
+}
+
+func (r *settings) JoinRequestChannel() Channel {
+	return r.joinRequestChannel
+}
+
+func (r *settings) JoinAcceptChannel() Channel {
+	return r.joinAcceptChannel
+}
+
+func (r *settings) UplinkChannel() Channel {
+	return r.uplinkChannel
+}

lora/lorawan/region/us915.go

@@ -0,0 +1,82 @@
+package region
+
+import "tinygo.org/x/drivers/lora"
+
+const (
+	US915_DEFAULT_PREAMBLE_LEN     = 8
+	US915_DEFAULT_TX_POWER_DBM     = 20
+	US915_FREQUENCY_INCREMENT_DR_0 = 200000  // only for 125 kHz Bandwidth
+	US915_FREQUENCY_INCREMENT_DR_4 = 1600000 // only for 500 kHz Bandwidth
+)
+
+type ChannelUS struct {
+	channel
+}
+
+func (c *ChannelUS) Next() bool {
+	switch c.Bandwidth() {
+	case lora.Bandwidth_125_0:
+		freq, ok := stepFrequency125(c.frequency)
+		if ok {
+			c.frequency = freq
+		} else {
+			c.frequency = lora.Mhz_903_0
+			c.bandwidth = lora.Bandwidth_500_0
+		}
+	case lora.Bandwidth_500_0:
+		freq, ok := stepFrequency500(c.frequency)
+		if ok {
+			c.frequency = freq
+		} else {
+			// there are no more frequencies to check after sweeping all 8 500 kHz channels
+			return false
+		}
+	}
+
+	return true
+}
+
+func stepFrequency125(freq uint32) (uint32, bool) {
+	f := freq + US915_FREQUENCY_INCREMENT_DR_0
+	if f >= lora.MHZ_915_0 {
+		return 0, false
+	}
+
+	return f, true
+}
+
+func stepFrequency500(freq uint32) (uint32, bool) {
+	f := freq + US915_FREQUENCY_INCREMENT_DR_4
+	if f >= lora.MHZ_915_0 {
+		return 0, false
+	}
+
+	return f, true
+}
+
+type SettingsUS915 struct {
+	settings
+}
+
+func US915() *SettingsUS915 {
+	return &SettingsUS915{settings: settings{
+		joinRequestChannel: &ChannelUS{channel: channel{lora.MHz_902_3,
+			lora.Bandwidth_125_0,
+			lora.SpreadingFactor10,
+			lora.CodingRate4_5,
+			US915_DEFAULT_PREAMBLE_LEN,
+			US915_DEFAULT_TX_POWER_DBM}},
+		joinAcceptChannel: &ChannelUS{channel: channel{0,
+			lora.Bandwidth_500_0,
+			lora.SpreadingFactor9,
+			lora.CodingRate4_5,
+			US915_DEFAULT_PREAMBLE_LEN,
+			US915_DEFAULT_TX_POWER_DBM}},
+		uplinkChannel: &ChannelUS{channel: channel{lora.Mhz_903_0,
+			lora.Bandwidth_500_0,
+			lora.SpreadingFactor9,
+			lora.CodingRate4_5,
+			US915_DEFAULT_PREAMBLE_LEN,
+			US915_DEFAULT_TX_POWER_DBM}},
+	}}
+}

lps22hb/lps22hb.go

@@ -5,6 +5,7 @@ package lps22hb
 
 import (
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a HTS221 device.
@@ -27,9 +28,9 @@ func (d *Device) ReadPressure() (pressure int32, err error) {
 
 	// read data
 	data := []byte{0, 0, 0}
-	d.bus.ReadRegister(d.Address, LPS22HB_PRESS_OUT_REG, data[:1])
-	d.bus.ReadRegister(d.Address, LPS22HB_PRESS_OUT_REG+1, data[1:2])
-	d.bus.ReadRegister(d.Address, LPS22HB_PRESS_OUT_REG+2, data[2:])
+	legacy.ReadRegister(d.bus, d.Address, LPS22HB_PRESS_OUT_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, LPS22HB_PRESS_OUT_REG+1, data[1:2])
+	legacy.ReadRegister(d.bus, d.Address, LPS22HB_PRESS_OUT_REG+2, data[2:])
 	pValue := float32(uint32(data[2])<<16|uint32(data[1])<<8|uint32(data[0])) / 4096.0
 
 	return int32(pValue * 1000), nil
@@ -39,7 +40,7 @@ func (d *Device) ReadPressure() (pressure int32, err error) {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(d.Address, LPS22HB_WHO_AM_I_REG, data)
+	legacy.ReadRegister(d.bus, d.Address, LPS22HB_WHO_AM_I_REG, data)
 	return data[0] == 0xB1
 }
 
@@ -49,8 +50,8 @@ func (d *Device) ReadTemperature() (temperature int32, err error) {
 
 	// read data
 	data := []byte{0, 0}
-	d.bus.ReadRegister(d.Address, LPS22HB_TEMP_OUT_REG, data[:1])
-	d.bus.ReadRegister(d.Address, LPS22HB_TEMP_OUT_REG+1, data[1:])
+	legacy.ReadRegister(d.bus, d.Address, LPS22HB_TEMP_OUT_REG, data[:1])
+	legacy.ReadRegister(d.bus, d.Address, LPS22HB_TEMP_OUT_REG+1, data[1:])
 	tValue := float32(int16(uint16(data[1])<<8|uint16(data[0]))) / 100.0
 
 	return int32(tValue * 1000), nil
@@ -61,12 +62,12 @@ func (d *Device) ReadTemperature() (temperature int32, err error) {
 // wait and trigger one shot in block update
 func (d *Device) waitForOneShot() {
 	// trigger one shot
-	d.bus.WriteRegister(d.Address, LPS22HB_CTRL2_REG, []byte{0x01})
+	legacy.WriteRegister(d.bus, d.Address, LPS22HB_CTRL2_REG, []byte{0x01})
 
 	// wait until one shot is cleared
 	data := []byte{1}
 	for {
-		d.bus.ReadRegister(d.Address, LPS22HB_CTRL2_REG, data)
+		legacy.ReadRegister(d.bus, d.Address, LPS22HB_CTRL2_REG, data)
 		if data[0]&0x01 == 0 {
 			break
 		}

lps22hb/lps22hb_generic.go

@@ -2,10 +2,10 @@
 
 package lps22hb
 
-import "tinygo.org/x/drivers"
+import "tinygo.org/x/drivers/internal/legacy"
 
 // Configure sets up the LPS22HB device for communication.
 func (d *Device) Configure() {
 	// set to block update mode
-	d.bus.WriteRegister(d.Address, LPS22HB_CTRL1_REG, []byte{0x02})
+	legacy.WriteRegister(d.bus, d.Address, LPS22HB_CTRL1_REG, []byte{0x02})
 }

lps22hb/lps22hb_nano_33_ble.go

@@ -5,6 +5,8 @@ package lps22hb
 import (
 	"machine"
 	"time"
+
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Configure sets up the LPS22HB device for communication.
@@ -18,5 +20,5 @@ func (d *Device) Configure() {
 	time.Sleep(10 * time.Millisecond)
 
 	// set to block update mode
-	d.bus.WriteRegister(d.Address, LPS22HB_CTRL1_REG, []byte{0x02})
+	legacy.WriteRegister(d.bus, d.Address, LPS22HB_CTRL1_REG, []byte{0x02})
 }

lsm303agr/lsm303agr.go

@@ -9,6 +9,7 @@ import (
 	"math"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an I2C connection to a LSM303AGR device.
@@ -52,8 +53,8 @@ func New(bus drivers.I2C) *Device {
 // It does two "who am I" requests and checks the responses.
 func (d *Device) Connected() bool {
 	data1, data2 := []byte{0}, []byte{0}
-	d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_WHO_AM_I, data1)
-	d.bus.ReadRegister(uint8(d.MagAddress), MAG_WHO_AM_I, data2)
+	legacy.ReadRegister(d.bus, uint8(d.AccelAddress), ACCEL_WHO_AM_I, data1)
+	legacy.ReadRegister(d.bus, uint8(d.MagAddress), MAG_WHO_AM_I, data2)
 	return data1[0] == 0x33 && data2[0] == 0x40
 }
 
@@ -104,26 +105,26 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 	data := d.buf[:1]
 
 	data[0] = byte(d.AccelDataRate<<4 | d.AccelPowerMode | 0x07)
-	err = d.bus.WriteRegister(uint8(d.AccelAddress), ACCEL_CTRL_REG1_A, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.AccelAddress), ACCEL_CTRL_REG1_A, data)
 	if err != nil {
 		return
 	}
 
 	data[0] = byte(0x80 | d.AccelRange<<4)
-	err = d.bus.WriteRegister(uint8(d.AccelAddress), ACCEL_CTRL_REG4_A, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.AccelAddress), ACCEL_CTRL_REG4_A, data)
 	if err != nil {
 		return
 	}
 
 	data[0] = byte(0xC0)
-	err = d.bus.WriteRegister(uint8(d.AccelAddress), TEMP_CFG_REG_A, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.AccelAddress), TEMP_CFG_REG_A, data)
 	if err != nil {
 		return
 	}
 
 	// Temperature compensation is on for magnetic sensor
 	data[0] = byte(0x80 | d.MagPowerMode<<4 | d.MagDataRate<<2 | d.MagSystemMode)
-	err = d.bus.WriteRegister(uint8(d.MagAddress), MAG_MR_REG_M, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.MagAddress), MAG_MR_REG_M, data)
 	if err != nil {
 		return
 	}
@@ -137,7 +138,7 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 // -1000000.
 func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_AUTO_INC, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.AccelAddress), ACCEL_OUT_AUTO_INC, data)
 	if err != nil {
 		return
 	}
@@ -183,14 +184,14 @@ func (d *Device) ReadMagneticField() (x, y, z int32, err error) {
 	if d.MagSystemMode == MAG_SYSTEM_SINGLE {
 		cmd := d.buf[:1]
 		cmd[0] = byte(0x80 | d.MagPowerMode<<4 | d.MagDataRate<<2 | d.MagSystemMode)
-		err = d.bus.WriteRegister(uint8(d.MagAddress), MAG_MR_REG_M, cmd)
+		err = legacy.WriteRegister(d.bus, uint8(d.MagAddress), MAG_MR_REG_M, cmd)
 		if err != nil {
 			return
 		}
 	}
 
 	data := d.buf[0:6]
-	d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_AUTO_INC, data)
+	legacy.ReadRegister(d.bus, uint8(d.MagAddress), MAG_OUT_AUTO_INC, data)
 
 	x = int32(int16((uint16(data[1])<<8 | uint16(data[0]))))
 	y = int32(int16((uint16(data[3])<<8 | uint16(data[2]))))
@@ -219,7 +220,7 @@ func (d *Device) ReadCompass() (h int32, err error) {
 func (d *Device) ReadTemperature() (t int32, err error) {
 
 	data := d.buf[:2]
-	err = d.bus.ReadRegister(uint8(d.AccelAddress), OUT_TEMP_AUTO_INC, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.AccelAddress), OUT_TEMP_AUTO_INC, data)
 	if err != nil {
 		return
 	}

lsm6ds3/lsm6ds3.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type AccelRange uint8
@@ -95,7 +96,7 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 	if cfg.IsPedometer { // CONFIGURE AS PEDOMETER
 		// Configure accelerometer: 2G + 26Hz
 		data[0] = uint8(ACCEL_2G) | uint8(ACCEL_SR_26)
-		err = d.bus.WriteRegister(uint8(d.Address), CTRL1_XL, data)
+		err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL1_XL, data)
 		if err != nil {
 			return
 		}
@@ -105,40 +106,40 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 		if cfg.ResetStepCounter {
 			data[0] |= 0x02
 		}
-		err = d.bus.WriteRegister(uint8(d.Address), CTRL10_C, data)
+		err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL10_C, data)
 		if err != nil {
 			return
 		}
 
 		// Enable pedometer
 		data[0] = 0x40
-		err = d.bus.WriteRegister(uint8(d.Address), TAP_CFG, data)
+		err = legacy.WriteRegister(d.bus, uint8(d.Address), TAP_CFG, data)
 		if err != nil {
 			return
 		}
 	} else { // NORMAL USE
 		// Configure accelerometer
 		data[0] = uint8(d.accelRange) | uint8(d.accelSampleRate) | uint8(d.accelBandWidth)
-		err = d.bus.WriteRegister(uint8(d.Address), CTRL1_XL, data)
+		err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL1_XL, data)
 		if err != nil {
 			return
 		}
 
 		// Set ODR bit
-		err = d.bus.ReadRegister(uint8(d.Address), CTRL4_C, data)
+		err = legacy.ReadRegister(d.bus, uint8(d.Address), CTRL4_C, data)
 		if err != nil {
 			return
 		}
 		data[0] = data[0] &^ BW_SCAL_ODR_ENABLED
 		data[0] |= BW_SCAL_ODR_ENABLED
-		err = d.bus.WriteRegister(uint8(d.Address), CTRL4_C, data)
+		err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL4_C, data)
 		if err != nil {
 			return
 		}
 
 		// Configure gyroscope
 		data[0] = uint8(d.gyroRange) | uint8(d.gyroSampleRate)
-		err = d.bus.WriteRegister(uint8(d.Address), CTRL2_G, data)
+		err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL2_G, data)
 		if err != nil {
 			return
 		}
@@ -151,7 +152,7 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := d.buf[:1]
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x69
 }
 
@@ -161,7 +162,7 @@ func (d *Device) Connected() bool {
 // -1000000.
 func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.Address), OUTX_L_XL, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_XL, data)
 	if err != nil {
 		return
 	}
@@ -186,7 +187,7 @@ func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 // you would get a value close to 360000000.
 func (d *Device) ReadRotation() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.Address), OUTX_L_G, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_G, data)
 	if err != nil {
 		return
 	}
@@ -210,7 +211,7 @@ func (d *Device) ReadRotation() (x, y, z int32, err error) {
 // ReadTemperature returns the temperature in celsius milli degrees (°C/1000)
 func (d *Device) ReadTemperature() (t int32, err error) {
 	data := d.buf[:2]
-	err = d.bus.ReadRegister(uint8(d.Address), OUT_TEMP_L, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUT_TEMP_L, data)
 	if err != nil {
 		return
 	}
@@ -223,7 +224,7 @@ func (d *Device) ReadTemperature() (t int32, err error) {
 // ReadSteps returns the steps of the pedometer
 func (d *Device) ReadSteps() (s int32, err error) {
 	data := d.buf[:2]
-	err = d.bus.ReadRegister(uint8(d.Address), STEP_COUNTER_L, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), STEP_COUNTER_L, data)
 	if err != nil {
 		return
 	}

lsm6ds3tr/lsm6ds3tr.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type AccelRange uint8
@@ -87,26 +88,26 @@ func (d *Device) doConfigure(cfg Configuration) (err error) {
 
 	// Configure accelerometer
 	data[0] = uint8(d.accelRange) | uint8(d.accelSampleRate)
-	err = d.bus.WriteRegister(uint8(d.Address), CTRL1_XL, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL1_XL, data)
 	if err != nil {
 		return
 	}
 
 	// Set ODR bit
-	err = d.bus.ReadRegister(uint8(d.Address), CTRL4_C, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), CTRL4_C, data)
 	if err != nil {
 		return
 	}
 	data[0] = data[0] &^ BW_SCAL_ODR_ENABLED
 	data[0] |= BW_SCAL_ODR_ENABLED
-	err = d.bus.WriteRegister(uint8(d.Address), CTRL4_C, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL4_C, data)
 	if err != nil {
 		return
 	}
 
 	// Configure gyroscope
 	data[0] = uint8(d.gyroRange) | uint8(d.gyroSampleRate)
-	err = d.bus.WriteRegister(uint8(d.Address), CTRL2_G, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL2_G, data)
 	if err != nil {
 		return
 	}
@@ -118,7 +119,7 @@ func (d *Device) doConfigure(cfg Configuration) (err error) {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := d.buf[:1]
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x6A
 }
 
@@ -128,7 +129,7 @@ func (d *Device) Connected() bool {
 // -1000000.
 func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.Address), OUTX_L_XL, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_XL, data)
 	if err != nil {
 		return
 	}
@@ -153,7 +154,7 @@ func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 // you would get a value close to 360000000.
 func (d *Device) ReadRotation() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.Address), OUTX_L_G, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_G, data)
 	if err != nil {
 		return
 	}
@@ -177,7 +178,7 @@ func (d *Device) ReadRotation() (x, y, z int32, err error) {
 // ReadTemperature returns the temperature in celsius milli degrees (°C/1000)
 func (d *Device) ReadTemperature() (t int32, err error) {
 	data := d.buf[:2]
-	err = d.bus.ReadRegister(uint8(d.Address), OUT_TEMP_L, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUT_TEMP_L, data)
 	if err != nil {
 		return
 	}

lsm6dsox/lsm6dsox.go

@@ -8,6 +8,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type AccelRange uint8
@@ -78,13 +79,13 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 	data := d.buf[:1]
 	// Configure accelerometer
 	data[0] = uint8(cfg.AccelRange) | uint8(cfg.AccelSampleRate)
-	err = d.bus.WriteRegister(uint8(d.Address), CTRL1_XL, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL1_XL, data)
 	if err != nil {
 		return
 	}
 	// Configure gyroscope
 	data[0] = uint8(cfg.GyroRange) | uint8(cfg.GyroSampleRate)
-	err = d.bus.WriteRegister(uint8(d.Address), CTRL2_G, data)
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL2_G, data)
 	if err != nil {
 		return
 	}
@@ -96,7 +97,7 @@ func (d *Device) Configure(cfg Configuration) (err error) {
 // It does a "who am I" request and checks the response.
 func (d *Device) Connected() bool {
 	data := d.buf[:1]
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x6C
 }
 
@@ -106,7 +107,7 @@ func (d *Device) Connected() bool {
 // -1000000.
 func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.Address), OUTX_L_A, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_A, data)
 	if err != nil {
 		return
 	}
@@ -122,7 +123,7 @@ func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 // you would get a value close to 360000000.
 func (d *Device) ReadRotation() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.Address), OUTX_L_G, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUTX_L_G, data)
 	if err != nil {
 		return
 	}
@@ -135,7 +136,7 @@ func (d *Device) ReadRotation() (x, y, z int32, err error) {
 // ReadTemperature returns the temperature in celsius milli degrees (°C/1000)
 func (d *Device) ReadTemperature() (t int32, err error) {
 	data := d.buf[:2]
-	err = d.bus.ReadRegister(uint8(d.Address), OUT_TEMP_L, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUT_TEMP_L, data)
 	if err != nil {
 		return
 	}

lsm9ds1/lsm9ds1.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 type AccelRange uint8
@@ -61,8 +62,8 @@ func New(bus drivers.I2C) *Device {
 // but "who am I" responses have unexpected values.
 func (d *Device) Connected() bool {
 	data1, data2 := d.buf[:1], d.buf[1:2]
-	d.bus.ReadRegister(d.AccelAddress, WHO_AM_I, data1)
-	d.bus.ReadRegister(d.MagAddress, WHO_AM_I_M, data2)
+	legacy.ReadRegister(d.bus, d.AccelAddress, WHO_AM_I, data1)
+	legacy.ReadRegister(d.bus, d.MagAddress, WHO_AM_I_M, data2)
 	return data1[0] == 0x68 && data2[0] == 0x3D
 }
 
@@ -72,7 +73,7 @@ func (d *Device) Connected() bool {
 // -1000000.
 func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.AccelAddress), OUT_X_L_XL, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.AccelAddress), OUT_X_L_XL, data)
 	if err != nil {
 		return
 	}
@@ -88,7 +89,7 @@ func (d *Device) ReadAcceleration() (x, y, z int32, err error) {
 // you would get a value close to 360000000.
 func (d *Device) ReadRotation() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.AccelAddress), OUT_X_L_G, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.AccelAddress), OUT_X_L_G, data)
 	if err != nil {
 		return
 	}
@@ -102,7 +103,7 @@ func (d *Device) ReadRotation() (x, y, z int32, err error) {
 // it in nT (nanotesla). 1 G (gauss) = 100_000 nT (nanotesla).
 func (d *Device) ReadMagneticField() (x, y, z int32, err error) {
 	data := d.buf[:6]
-	err = d.bus.ReadRegister(uint8(d.MagAddress), OUT_X_L_M, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.MagAddress), OUT_X_L_M, data)
 	if err != nil {
 		return
 	}
@@ -115,7 +116,7 @@ func (d *Device) ReadMagneticField() (x, y, z int32, err error) {
 // ReadTemperature returns the temperature in Celsius milli degrees (°C/1000)
 func (d *Device) ReadTemperature() (t int32, err error) {
 	data := d.buf[:2]
-	err = d.bus.ReadRegister(uint8(d.AccelAddress), OUT_TEMP_L, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.AccelAddress), OUT_TEMP_L, data)
 	if err != nil {
 		return
 	}
@@ -171,7 +172,7 @@ func (d *Device) doConfigure(cfg Configuration) (err error) {
 	// Configure accelerometer
 	// Sample rate & measurement range
 	data[0] = uint8(cfg.AccelSampleRate)<<5 | uint8(cfg.AccelRange)<<3
-	err = d.bus.WriteRegister(d.AccelAddress, CTRL_REG6_XL, data)
+	err = legacy.WriteRegister(d.bus, d.AccelAddress, CTRL_REG6_XL, data)
 	if err != nil {
 		return
 	}
@@ -179,7 +180,7 @@ func (d *Device) doConfigure(cfg Configuration) (err error) {
 	// Configure gyroscope
 	// Sample rate & measurement range
 	data[0] = uint8(cfg.GyroSampleRate)<<5 | uint8(cfg.GyroRange)<<3
-	err = d.bus.WriteRegister(d.AccelAddress, CTRL_REG1_G, data)
+	err = legacy.WriteRegister(d.bus, d.AccelAddress, CTRL_REG1_G, data)
 	if err != nil {
 		return
 	}
@@ -190,14 +191,14 @@ func (d *Device) doConfigure(cfg Configuration) (err error) {
 	// High-performance mode XY axis
 	// Sample rate
 	data[0] = 0b10000000 | 0b01000000 | uint8(cfg.MagSampleRate)<<2
-	err = d.bus.WriteRegister(d.MagAddress, CTRL_REG1_M, data)
+	err = legacy.WriteRegister(d.bus, d.MagAddress, CTRL_REG1_M, data)
 	if err != nil {
 		return
 	}
 
 	// Measurement range
 	data[0] = uint8(cfg.MagRange) << 5
-	err = d.bus.WriteRegister(d.MagAddress, CTRL_REG2_M, data)
+	err = legacy.WriteRegister(d.bus, d.MagAddress, CTRL_REG2_M, data)
 	if err != nil {
 		return
 	}
@@ -205,14 +206,14 @@ func (d *Device) doConfigure(cfg Configuration) (err error) {
 	// Continuous-conversion mode
 	// https://electronics.stackexchange.com/questions/237397/continuous-conversion-vs-single-conversion-mode
 	data[0] = 0b00000000
-	err = d.bus.WriteRegister(d.MagAddress, CTRL_REG3_M, data)
+	err = legacy.WriteRegister(d.bus, d.MagAddress, CTRL_REG3_M, data)
 	if err != nil {
 		return
 	}
 
 	// High-performance mode Z axis
 	data[0] = 0b00001000
-	err = d.bus.WriteRegister(d.MagAddress, CTRL_REG4_M, data)
+	err = legacy.WriteRegister(d.bus, d.MagAddress, CTRL_REG4_M, data)
 	if err != nil {
 		return
 	}

mag3110/mag3110.go

@@ -4,7 +4,10 @@
 // Datasheet: https://www.nxp.com/docs/en/data-sheet/MAG3110.pdf
 package mag3110 // import "tinygo.org/x/drivers/mag3110"
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device wraps an I2C connection to a MAG3110 device.
 type Device struct {
@@ -24,22 +27,22 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0xC4
 }
 
 // Configure sets up the device for communication.
 func (d Device) Configure() {
-	d.bus.WriteRegister(uint8(d.Address), CTRL_REG2, []uint8{0x80}) // Power down when not used
+	legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_REG2, []uint8{0x80}) // Power down when not used
 }
 
 // ReadMagnetic reads the vectors of the magnetic field of the device and
 // returns it.
 func (d Device) ReadMagnetic() (x int16, y int16, z int16) {
-	d.bus.WriteRegister(uint8(d.Address), CTRL_REG1, []uint8{0x1a}) // Request a measurement
+	legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_REG1, []uint8{0x1a}) // Request a measurement
 
 	data := make([]byte, 6)
-	d.bus.ReadRegister(uint8(d.Address), OUT_X_MSB, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), OUT_X_MSB, data)
 	x = int16((uint16(data[0]) << 8) | uint16(data[1]))
 	y = int16((uint16(data[2]) << 8) | uint16(data[3]))
 	z = int16((uint16(data[4]) << 8) | uint16(data[5]))
@@ -50,6 +53,6 @@ func (d Device) ReadMagnetic() (x int16, y int16, z int16) {
 // celsius milli degrees (°C/1000).
 func (d Device) ReadTemperature() (int32, error) {
 	data := make([]byte, 1)
-	d.bus.ReadRegister(uint8(d.Address), DIE_TEMP, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), DIE_TEMP, data)
 	return int32(data[0]) * 1000, nil
 }

mcp23017/device.go

@@ -8,6 +8,9 @@ package mcp23017
 
 import (
 	"errors"
+
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 const (
@@ -75,19 +78,12 @@ const (
 // address pins).
 var ErrInvalidHWAddress = errors.New("invalid hardware address")
 
-// I2C represents an I2C bus. It is notably implemented by the
-// machine.I2C type.
-type I2C interface {
-	ReadRegister(addr uint8, r uint8, buf []byte) error
-	WriteRegister(addr uint8, r uint8, buf []byte) error
-}
-
 // New returns a new MCP23017 device at the given I2C address
 // on the given bus.
 // It returns ErrInvalidHWAddress if the address isn't possible for the device.
 //
 // By default all pins are configured as inputs.
-func NewI2C(bus I2C, address uint8) (*Device, error) {
+func NewI2C(bus drivers.I2C, address uint8) (*Device, error) {
 	if address&hwAddressMask != hwAddress {
 		return nil, ErrInvalidHWAddress
 	}
@@ -115,7 +111,7 @@ type Device struct {
 
 	// bus holds the reference the I2C bus that the device lives on.
 	// It's an interface so that we can write tests for it.
-	bus  I2C
+	bus  drivers.I2C
 	addr uint8
 	// pins caches the most recent pin values that have been set.
 	// This enables us to change individual pin values without
@@ -259,7 +255,7 @@ func (d *Device) writeRegisterAB(r register, val Pins) error {
 	// and the fact that registers alternate between A and B
 	// to write both ports in a single operation.
 	buf := [2]byte{uint8(val), uint8(val >> 8)}
-	return d.bus.WriteRegister(d.addr, uint8(r&^portB), buf[:])
+	return legacy.WriteRegister(d.bus, d.addr, uint8(r&^portB), buf[:])
 }
 
 func (d *Device) readRegisterAB(r register) (Pins, error) {
@@ -267,7 +263,7 @@ func (d *Device) readRegisterAB(r register) (Pins, error) {
 	// and the fact that registers alternate between A and B
 	// to read both ports in a single operation.
 	var buf [2]byte
-	if err := d.bus.ReadRegister(d.addr, uint8(r), buf[:]); err != nil {
+	if err := legacy.ReadRegister(d.bus, d.addr, uint8(r), buf[:]); err != nil {
 		return Pins(0), err
 	}
 	return Pins(buf[0]) | (Pins(buf[1]) << 8), nil

mcp23017/multidevice.go

@@ -1,5 +1,7 @@
 package mcp23017
 
+import "tinygo.org/x/drivers"
+
 // All is a convenience value that represents all pins high (or all mask bits one).
 var All = PinSlice{0xffff}
 
@@ -12,7 +14,7 @@ type Devices []*Device
 // NewI2CDevices returns a Devices slice holding the Device values
 // for all the given addresses on the given bus.
 // When more than one bus is in use, create the slice yourself.
-func NewI2CDevices(bus I2C, addrs ...uint8) (Devices, error) {
+func NewI2CDevices(bus drivers.I2C, addrs ...uint8) (Devices, error) {
 	devs := make(Devices, len(addrs))
 	for i, addr := range addrs {
 		dev, err := NewI2C(bus, addr)

mma8653/mma8653.go

@@ -5,7 +5,10 @@
 // https://www.nxp.com/docs/en/data-sheet/MMA8653FC.pdf
 package mma8653 // import "tinygo.org/x/drivers/mma8653"
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device wraps an I2C connection to a MMA8653 device.
 type Device struct {
@@ -26,27 +29,27 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x5A
 }
 
 // Configure sets up the device for communication.
 func (d *Device) Configure(speed DataRate, sensitivity Sensitivity) error {
 	// Set mode to STANDBY to be able to change the sensitivity.
-	err := d.bus.WriteRegister(uint8(d.Address), CTRL_REG1, []uint8{0})
+	err := legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_REG1, []uint8{0})
 	if err != nil {
 		return err
 	}
 
 	// Set sensitivity (2G, 4G, 8G).
-	err = d.bus.WriteRegister(uint8(d.Address), XYZ_DATA_CFG, []uint8{uint8(sensitivity)})
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), XYZ_DATA_CFG, []uint8{uint8(sensitivity)})
 	if err != nil {
 		return err
 	}
 	d.sensitivity = sensitivity
 
 	// Set mode to ACTIVE and set the data rate.
-	err = d.bus.WriteRegister(uint8(d.Address), CTRL_REG1, []uint8{(uint8(speed) << 3) | 1})
+	err = legacy.WriteRegister(d.bus, uint8(d.Address), CTRL_REG1, []uint8{(uint8(speed) << 3) | 1})
 	if err != nil {
 		return err
 	}
@@ -59,7 +62,7 @@ func (d *Device) Configure(speed DataRate, sensitivity Sensitivity) error {
 // -1000000.
 func (d Device) ReadAcceleration() (x int32, y int32, z int32, err error) {
 	data := make([]byte, 6)
-	err = d.bus.ReadRegister(uint8(d.Address), OUT_X_MSB, data)
+	err = legacy.ReadRegister(d.bus, uint8(d.Address), OUT_X_MSB, data)
 	shift := uint32(8)
 	switch d.sensitivity {
 	case Sensitivity4G:

mpu6050/mpu6050.go

@@ -6,7 +6,10 @@
 // https://www.invensense.com/wp-content/uploads/2015/02/MPU-6000-Register-Map1.pdf
 package mpu6050 // import "tinygo.org/x/drivers/mpu6050"
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device wraps an I2C connection to a MPU6050 device.
 type Device struct {
@@ -26,7 +29,7 @@ func New(bus drivers.I2C) Device {
 // It does a "who am I" request and checks the response.
 func (d Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x68
 }
 
@@ -41,7 +44,7 @@ func (d Device) Configure() error {
 // -1000000.
 func (d Device) ReadAcceleration() (x int32, y int32, z int32) {
 	data := make([]byte, 6)
-	d.bus.ReadRegister(uint8(d.Address), ACCEL_XOUT_H, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), ACCEL_XOUT_H, data)
 	// Now do two things:
 	// 1. merge the two values to a 16-bit number (and cast to a 32-bit integer)
 	// 2. scale the value to bring it in the -1000000..1000000 range.
@@ -62,7 +65,7 @@ func (d Device) ReadAcceleration() (x int32, y int32, z int32) {
 // you would get a value close to 360000000.
 func (d Device) ReadRotation() (x int32, y int32, z int32) {
 	data := make([]byte, 6)
-	d.bus.ReadRegister(uint8(d.Address), GYRO_XOUT_H, data)
+	legacy.ReadRegister(d.bus, uint8(d.Address), GYRO_XOUT_H, data)
 	// First the value is converted from a pair of bytes to a signed 16-bit
 	// value and then to a signed 32-bit value to avoid integer overflow.
 	// Then the value is scaled to µ°/s (micro-degrees per second).
@@ -81,15 +84,15 @@ func (d Device) ReadRotation() (x int32, y int32, z int32) {
 
 // SetClockSource allows the user to configure the clock source.
 func (d Device) SetClockSource(source uint8) error {
-	return d.bus.WriteRegister(uint8(d.Address), PWR_MGMT_1, []uint8{source})
+	return legacy.WriteRegister(d.bus, uint8(d.Address), PWR_MGMT_1, []uint8{source})
 }
 
 // SetFullScaleGyroRange allows the user to configure the scale range for the gyroscope.
 func (d Device) SetFullScaleGyroRange(rng uint8) error {
-	return d.bus.WriteRegister(uint8(d.Address), GYRO_CONFIG, []uint8{rng})
+	return legacy.WriteRegister(d.bus, uint8(d.Address), GYRO_CONFIG, []uint8{rng})
 }
 
 // SetFullScaleAccelRange allows the user to configure the scale range for the accelerometer.
 func (d Device) SetFullScaleAccelRange(rng uint8) error {
-	return d.bus.WriteRegister(uint8(d.Address), ACCEL_CONFIG, []uint8{rng})
+	return legacy.WriteRegister(d.bus, uint8(d.Address), ACCEL_CONFIG, []uint8{rng})
 }

mpu9150/mpu9150.go

@@ -0,0 +1,99 @@
+// Package mpu9150 provides a driver for the MPU9150 accelerometer and gyroscope
+// made by InvenSense.
+//
+// Datasheets:
+// https://invensense.tdk.com/wp-content/uploads/2015/02/MPU-9150-Datasheet.pdf
+// https://inertialelements.com/documents/resources_page/MPU9150-register-manual.pdf
+
+package mpu9150
+
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
+
+// Device wraps an I2C connection to a MPU9150 device.
+type Device struct {
+	bus     drivers.I2C
+	Address uint16
+}
+
+// New creates a new MPU9150 connection. The I2C bus must already be
+// configured.
+//
+// This function only creates the Device object, it does not touch the device.
+func New(bus drivers.I2C) Device {
+	return Device{bus, Address}
+}
+
+// Connected returns whether a MPU9150 has been found.
+// It does a "who am I" request and checks the response.
+func (d Device) Connected() bool {
+	data := []byte{0}
+	legacy.ReadRegister(d.bus, uint8(d.Address), WHO_AM_I, data)
+	return data[0] == 0x68 // 4.32 Register 117 – Who Am I (MPU-9150 Register Map and Descriptions)
+}
+
+// Configure sets up the device for communication.
+func (d Device) Configure() error {
+	return d.SetClockSource(CLOCK_INTERNAL)
+}
+
+// ReadAcceleration reads the current acceleration from the device and returns
+// it in µg (micro-gravity). When one of the axes is pointing straight to Earth
+// and the sensor is not moving the returned value will be around 1000000 or
+// -1000000.
+func (d Device) ReadAcceleration(accel_axis byte) (x int32, y int32, z int32) {
+	data := make([]byte, 6)
+	legacy.ReadRegister(d.bus, uint8(d.Address), accel_axis, data)
+	// Now do two things:
+	// 1. merge the two values to a 16-bit number (and cast to a 32-bit integer)
+	// 2. scale the value to bring it in the -1000000..1000000 range.
+	//    This is done with a trick. What we do here is essentially multiply by
+	//    1000000 and divide by 16384 to get the original scale, but to avoid
+	//    overflow we do it at 1/64 of the value:
+	//      1000000 / 64 = 15625
+	//      16384   / 64 = 256
+	x = int32(int16((uint16(data[0])<<8)|uint16(data[1]))) * 15625 / 256
+	y = int32(int16((uint16(data[2])<<8)|uint16(data[3]))) * 15625 / 256
+	z = int32(int16((uint16(data[4])<<8)|uint16(data[5]))) * 15625 / 256
+	return
+}
+
+// ReadRotation reads the current rotation from the device and returns it in
+// µ°/s (micro-degrees/sec). This means that if you were to do a complete
+// rotation along one axis and while doing so integrate all values over time,
+// you would get a value close to 360000000.
+func (d Device) ReadRotation(gyro_axis byte) (x int32, y int32, z int32) {
+	data := make([]byte, 6)
+	legacy.ReadRegister(d.bus, uint8(d.Address), gyro_axis, data)
+	// First the value is converted from a pair of bytes to a signed 16-bit
+	// value and then to a signed 32-bit value to avoid integer overflow.
+	// Then the value is scaled to µ°/s (micro-degrees per second).
+	// This is done in the following steps:
+	// 1. Multiply by 250 * 1000_000
+	// 2. Divide by 32768
+	// The following calculation (x * 15625 / 2048 * 1000) is essentially the
+	// same but avoids overflow. First both operations are divided by 16 leading
+	// to multiply by 15625000 and divide by 2048, and then part of the multiply
+	// is done after the divide instead of before.
+	x = int32(int16((uint16(data[0])<<8)|uint16(data[1]))) * 15625 / 2048 * 1000
+	y = int32(int16((uint16(data[2])<<8)|uint16(data[3]))) * 15625 / 2048 * 1000
+	z = int32(int16((uint16(data[4])<<8)|uint16(data[5]))) * 15625 / 2048 * 1000
+	return
+}
+
+// SetClockSource allows the user to configure the clock source.
+func (d Device) SetClockSource(source uint8) error {
+	return legacy.WriteRegister(d.bus, uint8(d.Address), PWR_MGMT_1, []uint8{source})
+}
+
+// SetFullScaleGyroRange allows the user to configure the scale range for the gyroscope.
+func (d Device) SetFullScaleGyroRange(rng uint8) error {
+	return legacy.WriteRegister(d.bus, uint8(d.Address), GYRO_CONFIG, []uint8{rng})
+}
+
+// SetFullScaleAccelRange allows the user to configure the scale range for the accelerometer.
+func (d Device) SetFullScaleAccelRange(rng uint8) error {
+	return legacy.WriteRegister(d.bus, uint8(d.Address), ACCEL_CONFIG, []uint8{rng})
+}

mpu9150/registers.go

@@ -0,0 +1,131 @@
+package mpu9150
+
+// Constants/addresses used for I2C.
+
+// The I2C address which this device listens to.
+const Address = 0x68
+
+// Registers. Names, addresses and comments copied from the datasheet.
+const (
+	// Self test registers
+	SELF_TEST_X = 0x0D
+	SELF_TEST_Y = 0x0E
+	SELF_TEST_Z = 0x0F
+	SELF_TEST_A = 0x10
+
+	SMPLRT_DIV   = 0x19 // Sample rate divider
+	CONFIG       = 0x1A // Configuration
+	GYRO_CONFIG  = 0x1B // Gyroscope configuration
+	ACCEL_CONFIG = 0x1C // Accelerometer configuration
+	FIFO_EN      = 0x23 // FIFO enable
+
+	// I2C pass-through configuration
+	I2C_MST_CTRL   = 0x24
+	I2C_SLV0_ADDR  = 0x25
+	I2C_SLV0_REG   = 0x26
+	I2C_SLV0_CTRL  = 0x27
+	I2C_SLV1_ADDR  = 0x28
+	I2C_SLV1_REG   = 0x29
+	I2C_SLV1_CTRL  = 0x2A
+	I2C_SLV2_ADDR  = 0x2B
+	I2C_SLV2_REG   = 0x2C
+	I2C_SLV2_CTRL  = 0x2D
+	I2C_SLV3_ADDR  = 0x2E
+	I2C_SLV3_REG   = 0x2F
+	I2C_SLV3_CTRL  = 0x30
+	I2C_SLV4_ADDR  = 0x31
+	I2C_SLV4_REG   = 0x32
+	I2C_SLV4_DO    = 0x33
+	I2C_SLV4_CTRL  = 0x34
+	I2C_SLV4_DI    = 0x35
+	I2C_MST_STATUS = 0x36
+
+	// Interrupt configuration
+	INT_PIN_CFG = 0x37 // Interrupt pin/bypass enable configuration
+	INT_ENABLE  = 0x38 // Interrupt enable
+	INT_STATUS  = 0x3A // Interrupt status
+
+	// Accelerometer measurements
+	ACCEL_XOUT_H = 0x3B
+	ACCEL_XOUT_L = 0x3C
+	ACCEL_YOUT_H = 0x3D
+	ACCEL_YOUT_L = 0x3E
+	ACCEL_ZOUT_H = 0x3F
+	ACCEL_ZOUT_L = 0x40
+
+	// Temperature measurement
+	TEMP_OUT_H = 0x41
+	TEMP_OUT_L = 0x42
+
+	// Gyroscope measurements
+	GYRO_XOUT_H = 0x43
+	GYRO_XOUT_L = 0x44
+	GYRO_YOUT_H = 0x45
+	GYRO_YOUT_L = 0x46
+	GYRO_ZOUT_H = 0x47
+	GYRO_ZOUT_L = 0x48
+
+	// External sensor data
+	EXT_SENS_DATA_00 = 0x49
+	EXT_SENS_DATA_01 = 0x4A
+	EXT_SENS_DATA_02 = 0x4B
+	EXT_SENS_DATA_03 = 0x4C
+	EXT_SENS_DATA_04 = 0x4D
+	EXT_SENS_DATA_05 = 0x4E
+	EXT_SENS_DATA_06 = 0x4F
+	EXT_SENS_DATA_07 = 0x50
+	EXT_SENS_DATA_08 = 0x51
+	EXT_SENS_DATA_09 = 0x52
+	EXT_SENS_DATA_10 = 0x53
+	EXT_SENS_DATA_11 = 0x54
+	EXT_SENS_DATA_12 = 0x55
+	EXT_SENS_DATA_13 = 0x56
+	EXT_SENS_DATA_14 = 0x57
+	EXT_SENS_DATA_15 = 0x58
+	EXT_SENS_DATA_16 = 0x59
+	EXT_SENS_DATA_17 = 0x5A
+	EXT_SENS_DATA_18 = 0x5B
+	EXT_SENS_DATA_19 = 0x5C
+	EXT_SENS_DATA_20 = 0x5D
+	EXT_SENS_DATA_21 = 0x5E
+	EXT_SENS_DATA_22 = 0x5F
+	EXT_SENS_DATA_23 = 0x60
+
+	// I2C peripheral data out
+	I2C_SLV0_DO        = 0x63
+	I2C_SLV1_DO        = 0x64
+	I2C_SLV2_DO        = 0x65
+	I2C_SLV3_DO        = 0x66
+	I2C_MST_DELAY_CTRL = 0x67
+	SIGNAL_PATH_RESET  = 0x68
+
+	USER_CTRL   = 0x6A // User control
+	PWR_MGMT_1  = 0x6B // Power Management 1
+	PWR_MGMT_2  = 0x6C // Power Management 2
+	FIFO_COUNTH = 0x72 // FIFO count registers (high bits)
+	FIFO_COUNTL = 0x73 // FIFO count registers (low bits)
+	FIFO_R_W    = 0x74 // FIFO read/write
+	WHO_AM_I    = 0x75 // Who am I
+
+	// Clock settings  (4.28 Register 107 – Power Management 1)
+	CLOCK_INTERNAL               = 0x00
+	CLOCK_PLL_XGYRO              = 0x01
+	CLOCK_PLL_YGYRO              = 0x02
+	CLOCK_PLL_ZGYRO              = 0x03
+	CLOCK_PLL_EXTERNAL_32_768_KZ = 0x04
+	CLOCK_PLL_EXTERNAL_19_2_MHZ  = 0x05
+	CLOCK_RESERVED               = 0x06
+	CLOCK_STOP                   = 0x07
+
+	// Gyroscope settings (4.4 Register 27 – Gyroscope Configuration)
+	FS_RANGE_250  = 0x00
+	FS_RANGE_500  = 0x01
+	FS_RANGE_1000 = 0x02
+	FS_RANGE_2000 = 0x03
+
+	// Accelerometer settings (4.5 Register 28 – Accelerometer Configuration)
+	AFS_RANGE_2G  = 0x00
+	AFS_RANGE_4G  = 0x01
+	AFS_RANGE_8G  = 0x02
+	AFS_RANGE_16G = 0x03
+)

ndir/ndir.go

@@ -0,0 +1,288 @@
+package ndir
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+	"time"
+
+	"tinygo.org/x/drivers"
+)
+
+// Addr returns the I2C address given the solder pad configuration on the Sandbox Electronics i2c/uart converter.
+// When the resistor is connected between the left and middle pads the bit is said to be set
+// and a0 or a1 should be passed in as true.
+func Addr(a0, a1 bool) uint8 {
+	return 0b1001000 | b2u8(a0) | b2u8(a1)<<2
+}
+
+func b2u8(b bool) uint8 {
+	if b {
+		return 1
+	}
+	return 0
+}
+
+// See https://github.com/SandboxElectronics/NDIR/blob/master/NDIR_I2C/NDIR_I2C.cpp
+
+// General Registers
+const (
+	addrRHR       = 0x00
+	addrTHR       = 0x00
+	addrIER       = 0x01
+	addrFCR       = 0x02
+	addrIIR       = 0x02
+	addrLCR       = 0x03
+	addrMCR       = 0x04
+	addrLSR       = 0x05
+	addrMSR       = 0x06
+	addrSPR       = 0x07
+	addrTCR       = 0x06
+	addrTLR       = 0x07
+	addrTXLVL     = 0x08
+	addrRXLVL     = 0x09
+	addrIODIR     = 0x0A
+	addrIOSTATE   = 0x0B
+	addrIOINTENA  = 0x0C
+	addrIOCONTROL = 0x0E // This addr fails on write of 0x08?
+	addrEFCR      = 0x0F
+)
+
+// Special registers
+const (
+	addrDLL = 0x00
+	addrDLH = 1
+)
+
+const (
+	shortTxCooldown = time.Millisecond
+	longTxCooldown  = 10 * time.Millisecond
+	rxTimeout       = 100 * time.Millisecond
+)
+
+var (
+	cmd_readCO2                = [...]byte{0xFF, 0x01, 0x86, 0x00, 0x00, 0x00, 0x00, 0x00, 0x79}
+	cmd_measure                = [...]byte{0xFF, 0x01, 0x9C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x63}
+	cmd_calibrateZero          = [...]byte{0xFF, 0x01, 0x87, 0x00, 0x00, 0x00, 0x00, 0x00, 0x78}
+	cmd_enableAutoCalibration  = [...]byte{0xFF, 0x01, 0x79, 0xA0, 0x00, 0x00, 0x00, 0x00, 0xE6}
+	cmd_disableAutoCalibration = [...]byte{0xFF, 0x01, 0x79, 0x00, 0x00, 0x00, 0x00, 0x00, 0x86}
+)
+
+// DevI2C is a handle to a MH-Z16 NDIR CO2 Sensor using the I2C interface.
+type DevI2C struct {
+	bus             drivers.I2C
+	addr            uint8
+	nextAvail       time.Time
+	initTime        time.Time
+	lastMeasurement int32
+}
+
+// NewDevI2C returns a new NDIR device ready for use. It performs no I/O.
+func NewDevI2C(bus drivers.I2C, addr uint8) *DevI2C {
+	return &DevI2C{
+		bus:             bus,
+		addr:            addr,
+		lastMeasurement: -1,
+	}
+}
+
+// PPM returns the CO2 parts per million read in the last Update call.
+func (d *DevI2C) PPMCO2() int32 {
+	return d.lastMeasurement
+}
+
+var errInitWait = errors.New("ndir: must wait 12 seconds after init before reading concentration")
+
+// Update reads the CO2 concentration from the NDIR and stores it ready for the
+// PPM() method.
+func (d *DevI2C) Update(which drivers.Measurement) (err error) {
+	if which&drivers.Concentration == 0 {
+		return nil // NDIR only measures concentration, so nothing to do here.
+	}
+	if time.Since(d.initTime) < 12*time.Second {
+		// Wait 12 seconds before performing first read.
+		return nil
+	}
+	err = d.writeRegister(addrFCR, 0x07)
+	if err != nil {
+		return err
+	}
+	err = d.send(cmd_measure[:])
+	if err != nil {
+		return fmt.Errorf("sending cmd_measure: %w", err)
+	}
+	time.Sleep(11 * time.Millisecond)
+	var buf [9]byte
+	buf, err = d.receive()
+
+	if err != nil {
+		return fmt.Errorf("receiving during measure: %w", err)
+	}
+	if buf[0] != 0xff && buf[1] != 0x9c {
+		return fmt.Errorf("buffer rx bad values: %q", string(buf[:]))
+	}
+	var sum uint16
+	for i := 0; i < len(buf); i++ {
+		sum += uint16(buf[i])
+	}
+	mod := sum % 256
+	if mod != 0xff {
+		return fmt.Errorf("ndir checksum modulus got %#x, expected 0xff", mod)
+	}
+	ppm := uint32(buf[2])<<24 | uint32(buf[3])<<16 | uint32(buf[4])<<8 | uint32(buf[5])
+	d.lastMeasurement = int32(ppm)
+	return nil
+}
+
+func (d *DevI2C) Init() (err error) {
+	// AddrIOCONTROL write is always NACKed so ignore
+	// error here.
+	d.writeRegister(addrIOCONTROL, 0x08)
+
+	err = d.writeRegister(addrFCR, 0x07)
+	if err != nil {
+		return err
+	}
+	err = d.writeRegister(addrLCR, 0x83)
+	if err != nil {
+		return err
+	}
+	err = d.writeRegister(addrDLL, 0x60)
+	if err != nil {
+		return err
+	}
+	err = d.writeRegister(addrDLH, 0x00)
+	if err != nil {
+		return err
+	}
+	err = d.writeRegister(addrLCR, 0x03)
+	if err != nil {
+		return err
+	}
+	d.initTime = time.Now()
+	return nil
+}
+
+// CalibrateZero calibrates the NDIR to around 412ppm.
+func (d *DevI2C) CalibrateZero() error {
+	return d.enactCommand(cmd_calibrateZero[:])
+}
+
+// SetAutoCalibration can enable or disable the NDIR's auto calibration mode.
+func (d *DevI2C) SetAutoCalibration(enable bool) (err error) {
+	if enable {
+		err = d.enactCommand(cmd_enableAutoCalibration[:])
+	} else {
+		err = d.enactCommand(cmd_disableAutoCalibration[:])
+	}
+	return err
+}
+
+func (d *DevI2C) send(cmd []byte) error {
+	txlvl, err := d.ReadRegister(addrTXLVL)
+	if err != nil {
+		return err
+	}
+	if int(txlvl) < len(cmd) {
+		return fmt.Errorf("txlvl=%d less than length of command %d", txlvl, len(cmd))
+	}
+	return d.tx(append([]byte{addrTHR}, cmd...), nil)
+}
+
+func (d *DevI2C) receive() (cmd [9]byte, err error) {
+	start := time.Now()
+	n := uint8(9)
+	for n > 0 {
+		if time.Since(start) > rxTimeout {
+			return [9]byte{}, errors.New("NDIR rx timeout")
+		}
+		rxlvl, err := d.ReadRegister(addrRXLVL)
+		if err != nil {
+			return [9]byte{}, err
+		}
+		if rxlvl > n {
+			rxlvl = n
+		}
+		ptr := 9 - n
+		err = d.tx([]byte{addrRHR << 3}, cmd[ptr:ptr+rxlvl])
+		n -= rxlvl
+		if err != nil {
+			return [9]byte{}, err
+		}
+	}
+	return cmd, nil
+}
+
+func (d *DevI2C) enactCommand(cmd []byte) error {
+	if len(cmd) > 31 {
+		return errors.New("ndir: command too long")
+	}
+	// Most commands always start with the same FCR write here.
+	err := d.writeRegister(addrFCR, 0x07)
+	if err != nil {
+		return err
+	}
+	time.Sleep(longTxCooldown)
+
+	// C++ send method begins here.
+	got, err := d.ReadRegister(addrTXLVL)
+	if err != nil {
+		return err
+	}
+	if got < uint8(len(cmd)) {
+		return fmt.Errorf("ndir: txlevel=%d too low for command of length %d", got, len(cmd))
+	}
+	var buf [32]byte
+	buf[0] = addrTHR
+	n := 1 + copy(buf[1:], cmd)
+	err = d.tx(buf[:n], nil)
+	if err != nil {
+		return err
+	}
+	d.nextAvail.Add(longTxCooldown) // add some extra time.
+	return nil
+}
+
+func (d *DevI2C) writeRegister(addr, val uint8) (err error) {
+	return d.WriteRegisters(addr, []byte{val})
+}
+
+func (d *DevI2C) WriteRegisters(addr uint8, vals []byte) (err error) {
+	var buf [32]byte
+	if len(vals) > 31 {
+		return errors.New("can only write up to 31 bytes")
+	}
+	buf[0] = addr << 3
+	n := copy(buf[1:], vals)
+	err = d.tx(buf[:n+1], nil)
+	if err != nil {
+		err = fmt.Errorf("NDIR write %#x (%d) to %#x: %w", buf[1], len(vals), buf[0], err)
+	}
+	return err
+}
+
+func (d *DevI2C) ReadRegister(addr uint8) (uint8, error) {
+	var buf [2]byte
+	buf[0] = addr << 3
+	err := d.tx(buf[:1], buf[1:2])
+	if err != nil {
+		err = fmt.Errorf("NDIR read from %#x: %w", buf[0], err)
+	}
+	return buf[1], err
+}
+
+func (d *DevI2C) tx(w, r []byte) error {
+	wait := time.Until(d.nextAvail)
+	if wait > 0 {
+		// Try yielding process first, maybe there's a short time to wait and a schedule call is enough delay.
+		runtime.Gosched()
+		wait = time.Until(d.nextAvail)
+		if wait > 0 {
+			// If yielding did not work then perform sleep
+			time.Sleep(wait)
+		}
+	}
+	err := d.bus.Tx(uint16(d.addr), w, r)
+	d.nextAvail = time.Now().Add(shortTxCooldown)
+	return err
+}

pca9685/io.go

@@ -1,9 +1,11 @@
 package pca9685
 
+import "tinygo.org/x/drivers/internal/legacy"
+
 func (d *Dev) readReg(reg uint8, data []byte) error {
-	return d.bus.ReadRegister(d.addr, reg, data)
+	return legacy.ReadRegister(d.bus, d.addr, reg, data)
 }
 
 func (d *Dev) writeReg(reg uint8, data []byte) error {
-	return d.bus.WriteRegister(d.addr, reg, data)
+	return legacy.WriteRegister(d.bus, d.addr, reg, data)
 }

pcf8523/pcf8523.go

@@ -0,0 +1,89 @@
+// Package pcf8523 implements a driver for the PCF8523 CMOS Real-Time Clock (RTC)
+//
+// Datasheet: https://www.nxp.com/docs/en/data-sheet/PCF8523.pdf
+package pcf8523
+
+import (
+	"time"
+	"tinygo.org/x/drivers"
+)
+
+type Device struct {
+	bus     drivers.I2C
+	Address uint8
+}
+
+func New(i2c drivers.I2C) Device {
+	return Device{
+		bus:     i2c,
+		Address: DefaultAddress,
+	}
+}
+
+// Reset resets the device according to the datasheet section 8.3
+// This does not wipe the time registers, but resets control registers.
+func (d *Device) Reset() (err error) {
+	return d.bus.Tx(uint16(d.Address), []byte{rControl1, 0x58}, nil)
+}
+
+// SetPowerManagement configures how the device makes use of the backup battery, see
+// datasheet section 8.5
+func (d *Device) SetPowerManagement(b PowerManagement) error {
+	return d.setRegister(rControl3, byte(b)<<5, 0xE0)
+}
+
+func (d *Device) setRegister(reg uint8, value, mask uint8) error {
+	var buf [1]byte
+	err := d.bus.Tx(uint16(d.Address), []byte{reg}, buf[:])
+	if err != nil {
+		return err
+	}
+	buf[0] = (value & mask) | (buf[0] & (^mask))
+	return d.bus.Tx(uint16(d.Address), []byte{reg, buf[0]}, nil)
+}
+
+// SetTime sets the time and date
+func (d *Device) SetTime(t time.Time) error {
+	buf := []byte{
+		rSeconds,
+		bin2bcd(t.Second()),
+		bin2bcd(t.Minute()),
+		bin2bcd(t.Hour()),
+		bin2bcd(t.Day()),
+		bin2bcd(int(t.Weekday())),
+		bin2bcd(int(t.Month())),
+		bin2bcd(t.Year() - 2000),
+	}
+
+	return d.bus.Tx(uint16(d.Address), buf, nil)
+}
+
+// ReadTime returns the date and time
+func (d *Device) ReadTime() (time.Time, error) {
+	buf := make([]byte, 9)
+	err := d.bus.Tx(uint16(d.Address), []byte{rSeconds}, buf)
+	if err != nil {
+		return time.Time{}, err
+	}
+
+	seconds := bcd2bin(buf[0] & 0x7F)
+	minute := bcd2bin(buf[1] & 0x7F)
+	hour := bcd2bin(buf[2] & 0x3F)
+	day := bcd2bin(buf[3] & 0x3F)
+	//skipping weekday buf[4]
+	month := time.Month(bcd2bin(buf[5] & 0x1F))
+	year := int(bcd2bin(buf[6])) + 2000
+
+	t := time.Date(year, month, day, hour, minute, seconds, 0, time.UTC)
+	return t, nil
+}
+
+// bin2bcd converts binary to BCD
+func bin2bcd(dec int) uint8 {
+	return uint8(dec + 6*(dec/10))
+}
+
+// bcd2bin converts BCD to binary
+func bcd2bin(bcd uint8) int {
+	return int(bcd - 6*(bcd>>4))
+}

pcf8523/pcf8523_test.go

@@ -0,0 +1,91 @@
+package pcf8523
+
+import (
+	"encoding/hex"
+	"testing"
+	"time"
+	"tinygo.org/x/drivers/tester"
+)
+
+func TestDecToBcd_RoundTrip(t *testing.T) {
+
+	for i := 0; i < 60; i++ {
+		a := bcd2bin(bin2bcd(i))
+		if a != i {
+			t.Logf("not equal: %d != %d", a, i)
+			t.FailNow()
+		}
+	}
+}
+
+func TestDevice_Reset(t *testing.T) {
+	bus := tester.NewI2CBus(t)
+	fake := bus.NewDevice(DefaultAddress)
+
+	dev := New(bus)
+
+	err := dev.Reset()
+	assertNoError(t, err)
+
+	assertEquals(t, fake.Registers[rControl1], 0x58)
+}
+
+func TestDevice_SetPowerManagement(t *testing.T) {
+	bus := tester.NewI2CBus(t)
+	fake := bus.NewDevice(DefaultAddress)
+
+	dev := New(bus)
+
+	err := dev.SetPowerManagement(PowerManagement_SwitchOver_ModeStandard)
+	assertNoError(t, err)
+
+	assertEquals(t, fake.Registers[rControl3], 0b100<<5)
+}
+
+func TestDevice_SetTime(t *testing.T) {
+	bus := tester.NewI2CBus(t)
+	fake := bus.NewDevice(DefaultAddress)
+
+	dev := New(bus)
+
+	pointInTime, _ := time.Parse(time.RFC3339, "2023-09-12T22:35:50Z")
+	err := dev.SetTime(pointInTime)
+	assertNoError(t, err)
+
+	actual := hex.EncodeToString(fake.Registers[rSeconds : rSeconds+7])
+	expected := "50352212020923"
+	assertEquals(t, actual, expected)
+}
+
+func TestDevice_ReadTime(t *testing.T) {
+	bus := tester.NewI2CBus(t)
+	fake := bus.NewDevice(DefaultAddress)
+
+	expectedPointInTime := time.Date(2023, 9, 12, 17, 55, 42, 0, time.UTC)
+	fake.Registers[rSeconds] = 0x42
+	fake.Registers[rMinutes] = 0x55
+	fake.Registers[rHours] = 0x17
+	fake.Registers[rDays] = 0x12
+	fake.Registers[rMonths] = 0x9
+	fake.Registers[rYears] = 0x23
+
+	dev := New(bus)
+
+	//when
+	actualPointInTime, err := dev.ReadTime()
+
+	//then
+	assertNoError(t, err)
+	assertEquals(t, actualPointInTime, expectedPointInTime)
+}
+
+func assertNoError(t testing.TB, e error) {
+	if e != nil {
+		t.Fatalf("unexpected error: %v", e)
+	}
+}
+func assertEquals[T comparable](t testing.TB, a, b T) {
+	if a != b {
+		t.Fatalf("%v != %v", a, b)
+	}
+}

pcf8523/registers.go

@@ -0,0 +1,39 @@
+package pcf8523
+
+const DefaultAddress = 0x68
+
+// datasheet 8.5 Power management functions, table 11
+type PowerManagement byte
+
+const (
+	PowerManagement_SwitchOver_ModeStandard_LowDetection PowerManagement = 0b000
+	PowerManagement_SwitchOver_ModeDirect_LowDetection   PowerManagement = 0b001
+	PowerManagement_VddOnly_LowDetection                 PowerManagement = 0b010
+	PowerManagement_SwitchOver_ModeStandard              PowerManagement = 0b100
+	PowerManagement_SwitchOver_ModeDirect                PowerManagement = 0b101
+	PowerManagement_VddOnly                              PowerManagement = 0b101
+)
+
+// constants for all internal registers
+const (
+	rControl1               = 0x00 // Control_1
+	rControl2               = 0x01 // Control_2
+	rControl3               = 0x02 // Control_3
+	rSeconds                = 0x03 // Seconds
+	rMinutes                = 0x04 // Minutes
+	rHours                  = 0x05 // Hours
+	rDays                   = 0x06 // Days
+	rWeekdays               = 0x07 // Weekdays
+	rMonths                 = 0x08 // Months
+	rYears                  = 0x09 // Years
+	rMinuteAlarm            = 0x0A // Minute_alarm
+	rHourAlarm              = 0x0B // Hour_alarm
+	rDayAlarm               = 0x0C // Day_alarm
+	rWeekdayAlarm           = 0x0D // Weekday_alarm
+	rOffset                 = 0x0E // Offset
+	rTimerClkoutControl     = 0x0F // Tmr_CLKOUT_ctrl
+	rTimerAFrequencyControl = 0x10 // Tmr_A_freq_ctrl
+	rTimerARegister         = 0x11 // Tmr_A_reg
+	rTimerBFrequencyControl = 0x12 // Tmr_B_freq_ctrl
+	rTimerBRegister         = 0x13 // Tmr_B_reg
+)

pixel/image.go

@@ -0,0 +1,223 @@
+package pixel
+
+import (
+	"unsafe"
+)
+
+// Image buffer, used for working with the native image format of various
+// displays. It works a lot like a slice: it can be rescaled while reusing the
+// underlying buffer and should be passed around by value.
+type Image[T Color] struct {
+	width  int16
+	height int16
+	data   unsafe.Pointer
+}
+
+// NewImage creates a new image of the given size.
+func NewImage[T Color](width, height int) Image[T] {
+	if width < 0 || height < 0 || int(int16(width)) != width || int(int16(height)) != height {
+		// The width/height are stored as 16-bit integers and should never be
+		// negative.
+		panic("NewImage: width/height out of bounds")
+	}
+	var zeroColor T
+	var data unsafe.Pointer
+	if zeroColor.BitsPerPixel()%8 == 0 {
+		// Typical formats like RGB888 and RGB565.
+		// Each color starts at a whole byte offset from the start.
+		buf := make([]T, width*height)
+		data = unsafe.Pointer(&buf[0])
+	} else {
+		// Formats like RGB444 that have 12 bits per pixel.
+		// We access these as bytes, so allocate the buffer as a byte slice.
+		bufBits := width * height * zeroColor.BitsPerPixel()
+		bufBytes := (bufBits + 7) / 8
+		buf := make([]byte, bufBytes)
+		data = unsafe.Pointer(&buf[0])
+	}
+	return Image[T]{
+		width:  int16(width),
+		height: int16(height),
+		data:   data,
+	}
+}
+
+// Rescale returns a new Image buffer based on the img buffer.
+// The contents is undefined after the Rescale operation, and any modification
+// to the returned image will overwrite the underlying image buffer in undefined
+// ways. It will panic if width*height is larger than img.Len().
+func (img Image[T]) Rescale(width, height int) Image[T] {
+	if width*height > img.Len() {
+		panic("Image.Rescale size out of bounds")
+	}
+	return Image[T]{
+		width:  int16(width),
+		height: int16(height),
+		data:   img.data,
+	}
+}
+
+// LimitHeight returns a subimage with the bottom part cut off, as specified by
+// height.
+func (img Image[T]) LimitHeight(height int) Image[T] {
+	if height < 0 || height > int(img.height) {
+		panic("Image.LimitHeight: out of bounds")
+	}
+	return Image[T]{
+		width:  img.width,
+		height: int16(height),
+		data:   img.data,
+	}
+}
+
+// Len returns the number of pixels in this image buffer.
+func (img Image[T]) Len() int {
+	return int(img.width) * int(img.height)
+}
+
+// RawBuffer returns a byte slice that can be written directly to the screen
+// using DrawRGBBitmap8.
+func (img Image[T]) RawBuffer() []uint8 {
+	var zeroColor T
+	var numBytes int
+	if zeroColor.BitsPerPixel()%8 == 0 {
+		// Each color starts at a whole byte offset.
+		numBytes = int(unsafe.Sizeof(zeroColor)) * int(img.width) * int(img.height)
+	} else {
+		// Formats like RGB444 that aren't a whole number of bytes.
+		numBits := zeroColor.BitsPerPixel() * int(img.width) * int(img.height)
+		numBytes = (numBits + 7) / 8 // round up (see NewImage)
+	}
+	return unsafe.Slice((*byte)(img.data), numBytes)
+}
+
+// Size returns the image size.
+func (img Image[T]) Size() (int, int) {
+	return int(img.width), int(img.height)
+}
+
+func (img Image[T]) setPixel(index int, c T) {
+	var zeroColor T
+
+	if zeroColor.BitsPerPixel()%8 == 0 {
+		// Each color starts at a whole byte offset.
+		// This is the easy case.
+		offset := index * int(unsafe.Sizeof(zeroColor))
+		ptr := unsafe.Add(img.data, offset)
+		*((*T)(ptr)) = c
+		return
+	}
+
+	if c, ok := any(c).(RGB444BE); ok {
+		// Special case for RGB444.
+		bitIndex := index * zeroColor.BitsPerPixel()
+		if bitIndex%8 == 0 {
+			byteOffset := bitIndex / 8
+			ptr := (*[2]byte)(unsafe.Add(img.data, byteOffset))
+			ptr[0] = uint8(c >> 4)
+			ptr[1] = ptr[1]&0x0f | uint8(c)<<4 // change top bits
+		} else {
+			byteOffset := bitIndex / 8
+			ptr := (*[2]byte)(unsafe.Add(img.data, byteOffset))
+			ptr[0] = ptr[0]&0xf0 | uint8(c>>8) // change bottom bits
+			ptr[1] = uint8(c)
+		}
+		return
+	}
+
+	// TODO: the code for RGB444 should be generalized to support any bit size.
+	panic("todo: setPixel for odd bits per pixel")
+}
+
+// Set sets the pixel at x, y to the given color.
+// Use FillSolidColor to efficiently fill the entire image buffer.
+func (img Image[T]) Set(x, y int, c T) {
+	if uint(x) >= uint(int(img.width)) || uint(y) >= uint(int(img.height)) {
+		panic("Image.Set: out of bounds")
+	}
+	index := y*int(img.width) + x
+	img.setPixel(index, c)
+}
+
+// Get returns the color at the given index.
+func (img Image[T]) Get(x, y int) T {
+	if uint(x) >= uint(int(img.width)) || uint(y) >= uint(int(img.height)) {
+		panic("Image.Get: out of bounds")
+	}
+	var zeroColor T
+	index := y*int(img.width) + x // index into img.data
+
+	if zeroColor.BitsPerPixel()%8 == 0 {
+		// Colors like RGB565, RGB888, etc.
+		offset := index * int(unsafe.Sizeof(zeroColor))
+		ptr := unsafe.Add(img.data, offset)
+		return *((*T)(ptr))
+	}
+
+	if _, ok := any(zeroColor).(RGB444BE); ok {
+		// Special case for RGB444 that isn't stored in a neat byte multiple.
+		bitIndex := index * zeroColor.BitsPerPixel()
+		var c RGB444BE
+		if bitIndex%8 == 0 {
+			byteOffset := bitIndex / 8
+			ptr := (*[2]byte)(unsafe.Add(img.data, byteOffset))
+			c |= RGB444BE(ptr[0]) << 4
+			c |= RGB444BE(ptr[1] >> 4) // load top bits
+		} else {
+			byteOffset := bitIndex / 8
+			ptr := (*[2]byte)(unsafe.Add(img.data, byteOffset))
+			c |= RGB444BE(ptr[0]&0x0f) << 8 // load bottom bits
+			c |= RGB444BE(ptr[1])
+		}
+		return any(c).(T)
+	}
+
+	// TODO: generalize the above code.
+	panic("todo: Image.Get for odd bits per pixel")
+}
+
+// FillSolidColor fills the entire image with the given color.
+// This may be faster than setting individual pixels.
+func (img Image[T]) FillSolidColor(color T) {
+	var zeroColor T
+
+	// Fast pass for colors of 8, 16, 24, etc bytes in size.
+	if zeroColor.BitsPerPixel()%8 == 0 {
+		ptr := img.data
+		for i := 0; i < img.Len(); i++ {
+			// TODO: this can be optimized a lot.
+			// - The store can be done as a 32-bit integer, after checking for
+			//   alignment.
+			// - Perhaps the loop can be unrolled to improve copy performance.
+			*(*T)(ptr) = color
+			ptr = unsafe.Add(ptr, unsafe.Sizeof(zeroColor))
+		}
+		return
+	}
+
+	// Special case for RGB444.
+	if c, ok := any(color).(RGB444BE); ok {
+		// RGB444 can be stored in a more optimized way, by storing two colors
+		// at a time instead of setting each color individually. This avoids
+		// loading and masking the old color bits for the half-bytes.
+		var buf [3]uint8
+		buf[0] = uint8(c >> 4)
+		buf[1] = uint8(c)<<4 | uint8(c>>8)
+		buf[2] = uint8(c)
+		rawBuf := unsafe.Slice((*[3]byte)(img.data), img.Len()/2)
+		for i := 0; i < len(rawBuf); i++ {
+			rawBuf[i] = buf
+		}
+		if img.Len()%2 != 0 {
+			// The image contains an uneven number of pixels.
+			// This is uncommon, but it can happen and we have to handle it.
+			img.setPixel(img.Len()-1, color)
+		}
+		return
+	}
+
+	// Fallback for other color formats.
+	for i := 0; i < img.Len(); i++ {
+		img.setPixel(i, color)
+	}
+}

pixel/image_test.go

@@ -0,0 +1,64 @@
+package pixel_test
+
+import (
+	"image/color"
+	"testing"
+
+	"tinygo.org/x/drivers/pixel"
+)
+
+func TestImageRGB565BE(t *testing.T) {
+	image := pixel.NewImage[pixel.RGB565BE](5, 3)
+	if width, height := image.Size(); width != 5 && height != 3 {
+		t.Errorf("image.Size(): expected 5, 3 but got %d, %d", width, height)
+	}
+	for _, c := range []color.RGBA{
+		{R: 0xff, A: 0xff},
+		{G: 0xff, A: 0xff},
+		{B: 0xff, A: 0xff},
+		{R: 0x10, A: 0xff},
+		{G: 0x10, A: 0xff},
+		{B: 0x10, A: 0xff},
+	} {
+		image.Set(4, 2, pixel.NewColor[pixel.RGB565BE](c.R, c.G, c.B))
+		c2 := image.Get(4, 2).RGBA()
+		if c2 != c {
+			t.Errorf("failed to roundtrip color: expected %v but got %v", c, c2)
+		}
+	}
+}
+
+func TestImageRGB444BE(t *testing.T) {
+	image := pixel.NewImage[pixel.RGB444BE](5, 3)
+	if width, height := image.Size(); width != 5 && height != 3 {
+		t.Errorf("image.Size(): expected 5, 3 but got %d, %d", width, height)
+	}
+	for _, c := range []color.RGBA{
+		{R: 0xff, A: 0xff},
+		{G: 0xff, A: 0xff},
+		{B: 0xff, A: 0xff},
+		{R: 0x11, A: 0xff},
+		{G: 0x11, A: 0xff},
+		{B: 0x11, A: 0xff},
+	} {
+		encoded := pixel.NewColor[pixel.RGB444BE](c.R, c.G, c.B)
+		image.Set(0, 0, encoded)
+		image.Set(0, 1, encoded)
+		encoded2 := image.Get(0, 0)
+		encoded3 := image.Get(0, 1)
+		if encoded != encoded2 {
+			t.Errorf("failed to roundtrip color %v: expected %d but got %d", c, encoded, encoded2)
+		}
+		if encoded != encoded3 {
+			t.Errorf("failed to roundtrip color %v: expected %d but got %d", c, encoded, encoded3)
+		}
+		c2 := encoded2.RGBA()
+		if c2 != c {
+			t.Errorf("failed to roundtrip color: expected %v but got %v", c, c2)
+		}
+		c3 := encoded3.RGBA()
+		if c3 != c {
+			t.Errorf("failed to roundtrip color: expected %v but got %v", c, c3)
+		}
+	}
+}

pixel/pixel.go

@@ -0,0 +1,225 @@
+// Package pixel contains pixel format definitions used in various displays and
+// fast operations on them.
+//
+// This package is just a base for pixel operations, it is _not_ a graphics
+// library. It doesn't define circles, lines, etc - just the bare minimum
+// graphics operations needed plus the ones that need to be specialized per
+// pixel format.
+package pixel
+
+import (
+	"image/color"
+	"math/bits"
+)
+
+// Pixel with a particular color, matching the underlying hardware of a
+// particular display. Each pixel is at least 1 byte in size.
+// The color format is sRGB (or close to it) in all cases.
+type Color interface {
+	RGB888 | RGB565BE | RGB555 | RGB444BE
+
+	BaseColor
+}
+
+// BaseColor contains all the methods needed in a color format. This can be used
+// in display drivers that want to define their own Color type with just the
+// pixel formats the display supports.
+type BaseColor interface {
+	// The number of bits when stored.
+	// This means for example that RGB555 (which is still stored as a 16-bit
+	// integer) returns 16, while RGB444 returns 12.
+	BitsPerPixel() int
+
+	// Return the given color in color.RGBA format, which is always sRGB. The
+	// alpha channel is always 255.
+	RGBA() color.RGBA
+}
+
+// NewColor returns the given color based on the RGB values passed in the
+// parameters. The input value is assumed to be in sRGB color space.
+func NewColor[T Color](r, g, b uint8) T {
+	// Ugly cast from color.RGBA to T. The type switch and interface casts are
+	// trivially optimized away after instantiation.
+	var value T
+	switch any(value).(type) {
+	case RGB888:
+		return any(NewRGB888(r, g, b)).(T)
+	case RGB565BE:
+		return any(NewRGB565BE(r, g, b)).(T)
+	case RGB555:
+		return any(NewRGB555(r, g, b)).(T)
+	case RGB444BE:
+		return any(NewRGB444BE(r, g, b)).(T)
+	default:
+		panic("unknown color format")
+	}
+}
+
+// NewLinearColor returns the given color based on the linear RGB values passed
+// in the parameters. Use this if the RGB values are actually linear colors
+// (like those that are used in most RGB LEDs) and not when it is in the usual
+// sRGB color space (which is not linear).
+//
+// The input is assumed to be in the linear sRGB color space.
+func NewLinearColor[T Color](r, g, b uint8) T {
+	r = gammaEncodeTable[r]
+	g = gammaEncodeTable[g]
+	b = gammaEncodeTable[b]
+	return NewColor[T](r, g, b)
+}
+
+// RGB888 format, more commonly used in other places (desktop PC displays, CSS,
+// etc). Less commonly used on embedded displays due to the higher memory usage.
+type RGB888 struct {
+	R, G, B uint8
+}
+
+func NewRGB888(r, g, b uint8) RGB888 {
+	return RGB888{r, g, b}
+}
+
+func (c RGB888) BitsPerPixel() int {
+	return 24
+}
+
+func (c RGB888) RGBA() color.RGBA {
+	return color.RGBA{
+		R: c.R,
+		G: c.G,
+		B: c.B,
+		A: 255,
+	}
+}
+
+// RGB565 as used in many SPI displays. Stored as a big endian value.
+//
+// The color format in integer form is gggbbbbb_rrrrrggg on little endian
+// systems, which is the standard RGB565 format but with the top and bottom
+// bytes swapped.
+//
+// There are a few alternatives to this weird big-endian format, but they're not
+// great:
+//   - Storing the value in two 8-bit stores (to make the code endian-agnostic)
+//     incurs too much of a performance penalty.
+//   - Swapping the upper and lower bits just before storing. This is still less
+//     efficient than it could be, since colors are usually constructed once and
+//     then reused in many store operations. Doing the swap once instead of many
+//     times for each store is a performance win.
+type RGB565BE uint16
+
+func NewRGB565BE(r, g, b uint8) RGB565BE {
+	val := uint16(r&0xF8)<<8 +
+		uint16(g&0xFC)<<3 +
+		uint16(b&0xF8)>>3
+	// Swap endianness (make big endian).
+	// This is done using a single instruction on ARM (rev16).
+	// TODO: this should only be done on little endian systems, but TinyGo
+	// doesn't currently (2023) support big endian systems so it's difficult to
+	// test. Also, big endian systems don't seem fasionable these days.
+	val = bits.ReverseBytes16(val)
+	return RGB565BE(val)
+}
+
+func (c RGB565BE) BitsPerPixel() int {
+	return 16
+}
+
+func (c RGB565BE) RGBA() color.RGBA {
+	// Note: on ARM, the compiler uses a rev instruction instead of a rev16
+	// instruction. I wonder whether this can be optimized further to use rev16
+	// instead?
+	c = c<<8 | c>>8
+	color := color.RGBA{
+		R: uint8(c>>11) << 3,
+		G: uint8(c>>5) << 2,
+		B: uint8(c) << 3,
+		A: 255,
+	}
+	// Correct color rounding, so that 0xff roundtrips back to 0xff.
+	color.R |= color.R >> 5
+	color.G |= color.G >> 6
+	color.B |= color.B >> 5
+	return color
+}
+
+// Color format used on the GameBoy Advance among others.
+//
+// Colors are stored as native endian values, with bits 0bbbbbgg_gggrrrrr (red
+// is least significant, blue is most significant).
+type RGB555 uint16
+
+func NewRGB555(r, g, b uint8) RGB555 {
+	return RGB555(r)>>3 | (RGB555(g)>>3)<<5 | (RGB555(b)>>3)<<10
+}
+
+func (c RGB555) BitsPerPixel() int {
+	// 15 bits per pixel, but there are 16 bits when stored
+	return 16
+}
+
+func (c RGB555) RGBA() color.RGBA {
+	color := color.RGBA{
+		R: uint8(c>>10) << 3,
+		G: uint8(c>>5) << 3,
+		B: uint8(c) << 3,
+		A: 255,
+	}
+	// Correct color rounding, so that 0xff roundtrips back to 0xff.
+	color.R |= color.R >> 5
+	color.G |= color.G >> 5
+	color.B |= color.B >> 5
+	return color
+}
+
+// Color format that is supported by the ST7789 for example.
+// It may be a bit faster to use than RGB565BE on very slow SPI buses.
+//
+// The color format is native endian as a uint16 (0000rrrr_ggggbbbb), not big
+// endian which you might expect. I tried swapping the bytes, but it didn't have
+// much of a performance impact and made the code harder to read. It is stored
+// as a 12-bit big endian value in Image[RGB444BE] though.
+type RGB444BE uint16
+
+func NewRGB444BE(r, g, b uint8) RGB444BE {
+	return RGB444BE(r>>4)<<8 | RGB444BE(g>>4)<<4 | RGB444BE(b>>4)
+}
+
+func (c RGB444BE) BitsPerPixel() int {
+	return 12
+}
+
+func (c RGB444BE) RGBA() color.RGBA {
+	color := color.RGBA{
+		R: uint8(c>>8) << 4,
+		G: uint8(c>>4) << 4,
+		B: uint8(c>>0) << 4,
+		A: 255,
+	}
+	// Correct color rounding, so that 0xff roundtrips back to 0xff.
+	color.R |= color.R >> 4
+	color.G |= color.G >> 4
+	color.B |= color.B >> 4
+	return color
+}
+
+// Gamma brightness lookup table:
+// https://victornpb.github.io/gamma-table-generator
+// gamma = 0.45 steps = 256 range = 0-255
+var gammaEncodeTable = [256]uint8{
+	0, 21, 28, 34, 39, 43, 46, 50, 53, 56, 59, 61, 64, 66, 68, 70,
+	72, 74, 76, 78, 80, 82, 84, 85, 87, 89, 90, 92, 93, 95, 96, 98,
+	99, 101, 102, 103, 105, 106, 107, 109, 110, 111, 112, 114, 115, 116, 117, 118,
+	119, 120, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135,
+	136, 137, 138, 139, 140, 141, 142, 143, 144, 144, 145, 146, 147, 148, 149, 150,
+	151, 151, 152, 153, 154, 155, 156, 156, 157, 158, 159, 160, 160, 161, 162, 163,
+	164, 164, 165, 166, 167, 167, 168, 169, 170, 170, 171, 172, 173, 173, 174, 175,
+	175, 176, 177, 178, 178, 179, 180, 180, 181, 182, 182, 183, 184, 184, 185, 186,
+	186, 187, 188, 188, 189, 190, 190, 191, 192, 192, 193, 194, 194, 195, 195, 196,
+	197, 197, 198, 199, 199, 200, 200, 201, 202, 202, 203, 203, 204, 205, 205, 206,
+	206, 207, 207, 208, 209, 209, 210, 210, 211, 212, 212, 213, 213, 214, 214, 215,
+	215, 216, 217, 217, 218, 218, 219, 219, 220, 220, 221, 221, 222, 223, 223, 224,
+	224, 225, 225, 226, 226, 227, 227, 228, 228, 229, 229, 230, 230, 231, 231, 232,
+	232, 233, 233, 234, 234, 235, 235, 236, 236, 237, 237, 238, 238, 239, 239, 240,
+	240, 241, 241, 242, 242, 243, 243, 244, 244, 245, 245, 246, 246, 247, 247, 248,
+	248, 249, 249, 249, 250, 250, 251, 251, 252, 252, 253, 253, 254, 254, 255, 255,
+}

qmi8658c/qmi8658c.go

@@ -5,7 +5,10 @@
 // https://www.qstcorp.com/upload/pdf/202202/%EF%BC%88%E5%B7%B2%E4%BC%A0%EF%BC%89QMI8658C%20datasheet%20rev%200.9.pdf
 package qmi8656c
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device wraps the I2C connection to the QMIC8658 sensor
 type Device struct {
@@ -179,12 +182,12 @@ func (d *Device) ReadTemperature() (int32, error) {
 
 // Convenience method to read the register and avoid repetition.
 func (d *Device) ReadRegister(reg uint8, buf []byte) error {
-	return d.bus.ReadRegister(uint8(d.Address), reg, buf)
+	return legacy.ReadRegister(d.bus, uint8(d.Address), reg, buf)
 }
 
 // Convenience method to write the register and avoid repetition.
 func (d *Device) WriteRegister(reg uint8, v uint16) error {
 	data := []byte{byte(v)}
-	err := d.bus.WriteRegister(uint8(d.Address), reg, data)
+	err := legacy.WriteRegister(d.bus, uint8(d.Address), reg, data)
 	return err
 }

sensor.go

@@ -16,6 +16,8 @@ const (
 	MagneticField
 	Luminosity
 	Time
+	// Gas or liquid concentration, usually measured in ppm (parts per million).
+	Concentration
 	// Add Measurements above AllMeasurements.
 
 	// AllMeasurements is the OR of all Measurement values. It ensures all measurements are done.

sh1106/sh1106.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps an SPI connection.
@@ -51,7 +52,7 @@ type Buser interface {
 
 type VccMode uint8
 
-// NewI2C creates a new SSD1306 connection. The I2C wire must already be configured.
+// NewI2C creates a new SH1106 connection. The I2C wire must already be configured.
 func NewI2C(bus drivers.I2C) Device {
 	return Device{
 		bus: &I2CBus{
@@ -61,7 +62,7 @@ func NewI2C(bus drivers.I2C) Device {
 	}
 }
 
-// NewSPI creates a new SSD1306 connection. The SPI wire must already be configured.
+// NewSPI creates a new SH1106 connection. The SPI wire must already be configured.
 func NewSPI(bus drivers.SPI, dcPin, resetPin, csPin machine.Pin) Device {
 	dcPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	resetPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
@@ -283,9 +284,9 @@ func (d *Device) Tx(data []byte, isCommand bool) {
 // tx sends data to the display (I2CBus implementation)
 func (b *I2CBus) tx(data []byte, isCommand bool) {
 	if isCommand {
-		b.wire.WriteRegister(uint8(b.Address), 0x00, data)
+		legacy.WriteRegister(b.wire, uint8(b.Address), 0x00, data)
 	} else {
-		b.wire.WriteRegister(uint8(b.Address), 0x40, data)
+		legacy.WriteRegister(b.wire, uint8(b.Address), 0x40, data)
 	}
 }
 

sht4x/sht4x.go

@@ -0,0 +1,76 @@
+// Package sht4x provides a driver for the SHT4x digital humidity sensor series by Sensirion.
+// Datasheet: https://www.sensirion.com/media/documents/33FD6951/64D3B030/Sensirion_Datasheet_SHT4x.pdf
+package sht4x
+
+import (
+	"time"
+
+	"tinygo.org/x/drivers"
+)
+
+const DefaultAddress = 0x44
+
+const (
+	// single-shot, high-repeatability measurement
+	commandMeasurement = 0xfd
+)
+
+// Device represents a SHT4x sensor
+type Device struct {
+	bus     drivers.I2C
+	Address uint8
+}
+
+// New creates a new SHT4x connection. The I2C bus must already be
+// configured.
+func New(bus drivers.I2C) Device {
+	return Device{
+		bus:     bus,
+		Address: DefaultAddress,
+	}
+}
+
+// ReadTemperatureHumidity starts a measurement and then reads out the results. This function blocks
+// while the measurement is in progress.
+//
+// Temperature is returned in [degree Celsius], multiplied by 1000,
+// and relative humidity in [percent relative humidity], multiplied by 1000.
+func (d *Device) ReadTemperatureHumidity() (temperatureMilliCelsius int32, relativeHumidityMilliPercent int32, err error) {
+	rawTemp, rawHum, err := d.rawReadings()
+	if err != nil {
+		return 0, 0, err
+	}
+
+	// from the reference driver: https://github.com/Sensirion/embedded-sht/blob/fcc8a523210cc1241a2750899ff6b0f68f3ed212/sht4x/sht4x.c#L81
+	temperatureMilliCelsius = ((21875 * int32(rawTemp)) >> 13) - 45000
+	relativeHumidityMilliPercent = ((15625 * int32(rawHum)) >> 13) - 6000
+
+	return temperatureMilliCelsius, relativeHumidityMilliPercent, err
+}
+
+// rawReadings returns the sensor's raw values of the temperature and humidity
+func (d *Device) rawReadings() (uint16, uint16, error) {
+	err := d.bus.Tx(uint16(d.Address), []byte{commandMeasurement}, nil)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	// max time for measurement according to datasheet
+	time.Sleep(10 * time.Millisecond)
+
+	var data [6]byte
+	err = d.bus.Tx(uint16(d.Address), nil, data[:])
+	if err != nil {
+		return 0, 0, err
+	}
+
+	tTicks := readUint(data[0], data[1])
+	rhTicks := readUint(data[3], data[4])
+
+	return tTicks, rhTicks, nil
+}
+
+// readUint converts two bytes to uint16
+func readUint(msb byte, lsb byte) uint16 {
+	return (uint16(msb) << 8) | uint16(lsb)
+}

smoketest.go

@@ -133,7 +133,7 @@ func runSmokeTest(filename string) error {
 		result := <-job.resultChan
 		os.Stdout.Write(job.output.Bytes())
 		if result != nil {
-			return err
+			return result
 		}
 	}
 

smoketest.sh

@@ -4,6 +4,8 @@
 # avoid a race condition between writing the output and reading the result to
 # get an md5sum).
 
+
+tinygo build -size short -o ./build/test.hex -target=feather-rp2040 ./examples/adafruit4650
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/adt7410/main.go
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/adxl345/main.go
 tinygo build -size short -o ./build/test.hex -target=pybadge ./examples/amg88xx
@@ -13,6 +15,7 @@ tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/apa
 tinygo build -size short -o ./build/test.hex -target=microbit ./examples/at24cx/main.go
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/bh1750/main.go
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/blinkm/main.go
+tinygo build -size short -o ./build/test.hex -target=pinetime     ./examples/bma42x/main.go
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/bmi160/main.go
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/bmp180/main.go
 tinygo build -size short -o ./build/test.hex -target=itsybitsy-m0 ./examples/bmp280/main.go
@@ -61,6 +64,7 @@ tinygo build -size short -o ./build/test.hex -target=microbit ./examples/pcd8544
 tinygo build -size short -o ./build/test.hex -target=arduino ./examples/servo
 tinygo build -size short -o ./build/test.hex -target=pybadge ./examples/shifter/main.go
 tinygo build -size short -o ./build/test.hex -target=microbit ./examples/sht3x/main.go
+tinygo build -size short -o ./build/test.hex -target=microbit ./examples/sht4x/main.go
 tinygo build -size short -o ./build/test.hex -target=microbit ./examples/shtc3/main.go
 tinygo build -size short -o ./build/test.hex -target=microbit ./examples/ssd1306/i2c_128x32/main.go
 tinygo build -size short -o ./build/test.hex -target=microbit ./examples/ssd1306/spi_128x64/main.go
@@ -100,6 +104,7 @@ tinygo build -size short -o ./build/test.hex -target=circuitplay-express ./examp
 tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/max72xx/main.go
 tinygo build -size short -o ./build/test.hex -target=feather-m0 ./examples/dht/main.go
 # tinygo build -size short -o ./build/test.hex -target=arduino ./examples/keypad4x4/main.go
+tinygo build -size short -o ./build/test.hex -target=feather-rp2040 ./examples/pcf8523/
 tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/alarm/
 tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/clkout/
 tinygo build -size short -o ./build/test.hex -target=xiao ./examples/pcf8563/time/
@@ -126,4 +131,9 @@ tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/d
 tinygo build -size short -o ./build/test.hex -target=nucleo-wl55jc ./examples/lora/lorawan/atcmd/
 tinygo build -size short -o ./build/test.uf2 -target=pico ./examples/as560x/main.go
 tinygo build -size short -o ./build/test.uf2 -target=pico ./examples/mpu6886/main.go
-tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/ttp229/main.go
+tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/ttp229/main.go
+tinygo build -size short -o ./build/test.hex -target=pico ./examples/ndir/main_ndir.go
+tinygo build -size short -o ./build/test.hex -target=microbit ./examples/ndir/main_ndir.go
+tinygo build -size short -o ./build/test.hex -target=arduino-nano33 ./examples/ndir/main_ndir.go
+tinygo build -size short -o ./build/test.uf2 -target=pico ./examples/mpu9150/main.go
+tinygo build -size short -o ./build/test.hex -target=macropad-rp2040 ./examples/sh1106/macropad_spi

ssd1306/ssd1306.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
 )
 
 // Device wraps I2C or SPI connection.
@@ -44,9 +45,9 @@ type SPIBus struct {
 }
 
 type Buser interface {
-	configure()
-	tx(data []byte, isCommand bool)
-	setAddress(address uint16)
+	configure() error
+	tx(data []byte, isCommand bool) error
+	setAddress(address uint16) error
 }
 
 type VccMode uint8
@@ -192,8 +193,7 @@ func (d *Device) Display() error {
 		d.Command(uint8(d.height/8) - 1)
 	}
 
-	d.Tx(d.buffer, false)
-	return nil
+	return d.Tx(d.buffer, false)
 }
 
 // SetPixel enables or disables a pixel in the buffer
@@ -243,21 +243,23 @@ func (d *Device) Command(command uint8) {
 }
 
 // setAddress sets the address to the I2C bus
-func (b *I2CBus) setAddress(address uint16) {
+func (b *I2CBus) setAddress(address uint16) error {
 	b.Address = address
+	return nil
 }
 
 // setAddress does nothing, but it's required to avoid reflection
-func (b *SPIBus) setAddress(address uint16) {
+func (b *SPIBus) setAddress(address uint16) error {
 	// do nothing
 	println("trying to Configure an address on a SPI device")
+	return nil
 }
 
 // configure does nothing, but it's required to avoid reflection
-func (b *I2CBus) configure() {}
+func (b *I2CBus) configure() error { return nil }
 
 // configure configures some pins with the SPI bus
-func (b *SPIBus) configure() {
+func (b *SPIBus) configure() error {
 	b.csPin.Low()
 	b.dcPin.Low()
 	b.resetPin.Low()
@@ -267,31 +269,35 @@ func (b *SPIBus) configure() {
 	b.resetPin.Low()
 	time.Sleep(10 * time.Millisecond)
 	b.resetPin.High()
+
+	return nil
 }
 
 // Tx sends data to the display
-func (d *Device) Tx(data []byte, isCommand bool) {
-	d.bus.tx(data, isCommand)
+func (d *Device) Tx(data []byte, isCommand bool) error {
+	return d.bus.tx(data, isCommand)
 }
 
 // tx sends data to the display (I2CBus implementation)
-func (b *I2CBus) tx(data []byte, isCommand bool) {
+func (b *I2CBus) tx(data []byte, isCommand bool) error {
 	if isCommand {
-		b.wire.WriteRegister(uint8(b.Address), 0x00, data)
+		return legacy.WriteRegister(b.wire, uint8(b.Address), 0x00, data)
 	} else {
-		b.wire.WriteRegister(uint8(b.Address), 0x40, data)
+		return legacy.WriteRegister(b.wire, uint8(b.Address), 0x40, data)
 	}
 }
 
 // tx sends data to the display (SPIBus implementation)
-func (b *SPIBus) tx(data []byte, isCommand bool) {
+func (b *SPIBus) tx(data []byte, isCommand bool) error {
+	var err error
+
 	if isCommand {
 		b.csPin.High()
 		time.Sleep(1 * time.Millisecond)
 		b.dcPin.Low()
 		b.csPin.Low()
 
-		b.wire.Tx(data, nil)
+		err = b.wire.Tx(data, nil)
 		b.csPin.High()
 	} else {
 		b.csPin.High()
@@ -299,9 +305,11 @@ func (b *SPIBus) tx(data []byte, isCommand bool) {
 		b.dcPin.High()
 		b.csPin.Low()
 
-		b.wire.Tx(data, nil)
+		err = b.wire.Tx(data, nil)
 		b.csPin.High()
 	}
+
+	return err
 }
 
 // Size returns the current size of the display.

st7735/st7735.go

@@ -11,6 +11,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/pixel"
 )
 
 type Model uint8
@@ -20,12 +21,23 @@ type Model uint8
 // Deprecated: use drivers.Rotation instead.
 type Rotation = drivers.Rotation
 
+// Pixel formats supported by the st7735 driver.
+type Color interface {
+	pixel.RGB444BE | pixel.RGB565BE
+
+	pixel.BaseColor
+}
+
 var (
 	errOutOfBounds = errors.New("rectangle coordinates outside display area")
 )
 
 // Device wraps an SPI connection.
-type Device struct {
+type Device = DeviceOf[pixel.RGB565BE]
+
+// DeviceOf is a generic version of Device, which supports different pixel
+// formats.
+type DeviceOf[T Color] struct {
 	bus          drivers.SPI
 	dcPin        machine.Pin
 	resetPin     machine.Pin
@@ -39,7 +51,7 @@ type Device struct {
 	batchLength  int16
 	model        Model
 	isBGR        bool
-	batchData    []uint8
+	batchData    pixel.Image[T] // "image" with width, height of (batchLength, 1)
 }
 
 // Config is the configuration for the display
@@ -54,11 +66,17 @@ type Config struct {
 
 // New creates a new ST7735 connection. The SPI wire must already be configured.
 func New(bus drivers.SPI, resetPin, dcPin, csPin, blPin machine.Pin) Device {
+	return NewOf[pixel.RGB565BE](bus, resetPin, dcPin, csPin, blPin)
+}
+
+// NewOf creates a new ST7735 connection with a particular pixel format. The SPI
+// wire must already be configured.
+func NewOf[T Color](bus drivers.SPI, resetPin, dcPin, csPin, blPin machine.Pin) DeviceOf[T] {
 	dcPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	resetPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	csPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	blPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
-	return Device{
+	return DeviceOf[T]{
 		bus:      bus,
 		dcPin:    dcPin,
 		resetPin: resetPin,
@@ -68,7 +86,7 @@ func New(bus drivers.SPI, resetPin, dcPin, csPin, blPin machine.Pin) Device {
 }
 
 // Configure initializes the display with default configuration
-func (d *Device) Configure(cfg Config) {
+func (d *DeviceOf[T]) Configure(cfg Config) {
 	d.model = cfg.Model
 	if cfg.Width != 0 {
 		d.width = cfg.Width
@@ -93,7 +111,7 @@ func (d *Device) Configure(cfg Config) {
 		d.batchLength = d.height
 	}
 	d.batchLength += d.batchLength & 1
-	d.batchData = make([]uint8, d.batchLength*2)
+	d.batchData = pixel.NewImage[T](int(d.batchLength), 1)
 
 	// reset the device
 	d.resetPin.High()
@@ -142,8 +160,16 @@ func (d *Device) Configure(cfg Config) {
 	d.Data(0xEE)
 	d.Command(VMCTR1)
 	d.Data(0x0E)
+
+	// Set the color format depending on the generic type.
 	d.Command(COLMOD)
-	d.Data(0x05)
+	var zeroColor T
+	switch any(zeroColor).(type) {
+	case pixel.RGB444BE:
+		d.Data(0x03) // 12 bits per pixel
+	default:
+		d.Data(0x05) // 16 bits per pixel
+	}
 
 	if d.model == GREENTAB {
 		d.InvertColors(false)
@@ -204,12 +230,12 @@ func (d *Device) Configure(cfg Config) {
 }
 
 // Display does nothing, there's no buffer as it might be too big for some boards
-func (d *Device) Display() error {
+func (d *DeviceOf[T]) Display() error {
 	return nil
 }
 
 // SetPixel sets a pixel in the screen
-func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
+func (d *DeviceOf[T]) SetPixel(x int16, y int16, c color.RGBA) {
 	w, h := d.Size()
 	if x < 0 || y < 0 || x >= w || y >= h {
 		return
@@ -218,7 +244,7 @@ func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
 }
 
 // setWindow prepares the screen to be modified at a given rectangle
-func (d *Device) setWindow(x, y, w, h int16) {
+func (d *DeviceOf[T]) setWindow(x, y, w, h int16) {
 	if d.rotation == drivers.Rotation0 || d.rotation == drivers.Rotation180 {
 		x += d.columnOffset
 		y += d.rowOffset
@@ -234,7 +260,9 @@ func (d *Device) setWindow(x, y, w, h int16) {
 }
 
 // SetScrollWindow sets an area to scroll with fixed top and bottom parts of the display
-func (d *Device) SetScrollArea(topFixedArea, bottomFixedArea int16) {
+func (d *DeviceOf[T]) SetScrollArea(topFixedArea, bottomFixedArea int16) {
+	// TODO: this code is broken, see the st7789 and ili9341 implementations for
+	// how to do this correctly.
 	d.Command(VSCRDEF)
 	d.Tx([]uint8{
 		uint8(topFixedArea >> 8), uint8(topFixedArea),
@@ -244,38 +272,32 @@ func (d *Device) SetScrollArea(topFixedArea, bottomFixedArea int16) {
 }
 
 // SetScroll sets the vertical scroll address of the display.
-func (d *Device) SetScroll(line int16) {
+func (d *DeviceOf[T]) SetScroll(line int16) {
 	d.Command(VSCRSADD)
 	d.Tx([]uint8{uint8(line >> 8), uint8(line)}, false)
 }
 
 // SpotScroll returns the display to its normal state
-func (d *Device) StopScroll() {
+func (d *DeviceOf[T]) StopScroll() {
 	d.Command(NORON)
 }
 
 // FillRectangle fills a rectangle at a given coordinates with a color
-func (d *Device) FillRectangle(x, y, width, height int16, c color.RGBA) error {
+func (d *DeviceOf[T]) FillRectangle(x, y, width, height int16, c color.RGBA) error {
 	k, i := d.Size()
 	if x < 0 || y < 0 || width <= 0 || height <= 0 ||
 		x >= k || (x+width) > k || y >= i || (y+height) > i {
 		return errors.New("rectangle coordinates outside display area")
 	}
 	d.setWindow(x, y, width, height)
-	c565 := RGBATo565(c)
-	c1 := uint8(c565 >> 8)
-	c2 := uint8(c565)
 
-	for i = 0; i < d.batchLength; i++ {
-		d.batchData[i*2] = c1
-		d.batchData[i*2+1] = c2
-	}
+	d.batchData.FillSolidColor(pixel.NewColor[T](c.R, c.G, c.B))
 	i = width * height
 	for i > 0 {
 		if i >= d.batchLength {
-			d.Tx(d.batchData, false)
+			d.Tx(d.batchData.RawBuffer(), false)
 		} else {
-			d.Tx(d.batchData[:i*2], false)
+			d.Tx(d.batchData.Rescale(int(i), 1).RawBuffer(), false)
 		}
 		i -= d.batchLength
 	}
@@ -283,7 +305,9 @@ func (d *Device) FillRectangle(x, y, width, height int16, c color.RGBA) error {
 }
 
 // DrawRGBBitmap8 copies an RGB bitmap to the internal buffer at given coordinates
-func (d *Device) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
+//
+// Deprecated: use DrawBitmap instead.
+func (d *DeviceOf[T]) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
 	k, i := d.Size()
 	if x < 0 || y < 0 || w <= 0 || h <= 0 ||
 		x >= k || (x+w) > k || y >= i || (y+h) > i {
@@ -294,8 +318,15 @@ func (d *Device) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
 	return nil
 }
 
+// DrawBitmap copies the bitmap to the internal buffer on the screen at the
+// given coordinates. It returns once the image data has been sent completely.
+func (d *DeviceOf[T]) DrawBitmap(x, y int16, bitmap pixel.Image[T]) error {
+	width, height := bitmap.Size()
+	return d.DrawRGBBitmap8(x, y, bitmap.RawBuffer(), int16(width), int16(height))
+}
+
 // FillRectangle fills a rectangle at a given coordinates with a buffer
-func (d *Device) FillRectangleWithBuffer(x, y, width, height int16, buffer []color.RGBA) error {
+func (d *DeviceOf[T]) FillRectangleWithBuffer(x, y, width, height int16, buffer []color.RGBA) error {
 	k, l := d.Size()
 	if x < 0 || y < 0 || width <= 0 || height <= 0 ||
 		x >= k || (x+width) > k || y >= l || (y+height) > l {
@@ -313,17 +344,14 @@ func (d *Device) FillRectangleWithBuffer(x, y, width, height int16, buffer []col
 	for k > 0 {
 		for i := int16(0); i < d.batchLength; i++ {
 			if offset+i < l {
-				c565 := RGBATo565(buffer[offset+i])
-				c1 := uint8(c565 >> 8)
-				c2 := uint8(c565)
-				d.batchData[i*2] = c1
-				d.batchData[i*2+1] = c2
+				c := buffer[offset+i]
+				d.batchData.Set(int(i), 0, pixel.NewColor[T](c.R, c.G, c.B))
 			}
 		}
 		if k >= d.batchLength {
-			d.Tx(d.batchData, false)
+			d.Tx(d.batchData.RawBuffer(), false)
 		} else {
-			d.Tx(d.batchData[:k*2], false)
+			d.Tx(d.batchData.Rescale(int(k), 1).RawBuffer(), false)
 		}
 		k -= d.batchLength
 		offset += d.batchLength
@@ -332,7 +360,7 @@ func (d *Device) FillRectangleWithBuffer(x, y, width, height int16, buffer []col
 }
 
 // DrawFastVLine draws a vertical line faster than using SetPixel
-func (d *Device) DrawFastVLine(x, y0, y1 int16, c color.RGBA) {
+func (d *DeviceOf[T]) DrawFastVLine(x, y0, y1 int16, c color.RGBA) {
 	if y0 > y1 {
 		y0, y1 = y1, y0
 	}
@@ -340,7 +368,7 @@ func (d *Device) DrawFastVLine(x, y0, y1 int16, c color.RGBA) {
 }
 
 // DrawFastHLine draws a horizontal line faster than using SetPixel
-func (d *Device) DrawFastHLine(x0, x1, y int16, c color.RGBA) {
+func (d *DeviceOf[T]) DrawFastHLine(x0, x1, y int16, c color.RGBA) {
 	if x0 > x1 {
 		x0, x1 = x1, x0
 	}
@@ -348,7 +376,7 @@ func (d *Device) DrawFastHLine(x0, x1, y int16, c color.RGBA) {
 }
 
 // FillScreen fills the screen with a given color
-func (d *Device) FillScreen(c color.RGBA) {
+func (d *DeviceOf[T]) FillScreen(c color.RGBA) {
 	if d.rotation == drivers.Rotation0 || d.rotation == drivers.Rotation180 {
 		d.FillRectangle(0, 0, d.width, d.height, c)
 	} else {
@@ -357,12 +385,12 @@ func (d *Device) FillScreen(c color.RGBA) {
 }
 
 // Rotation returns the currently configured rotation.
-func (d *Device) Rotation() drivers.Rotation {
+func (d *DeviceOf[T]) Rotation() drivers.Rotation {
 	return d.rotation
 }
 
 // SetRotation changes the rotation of the device (clock-wise)
-func (d *Device) SetRotation(rotation drivers.Rotation) error {
+func (d *DeviceOf[T]) SetRotation(rotation drivers.Rotation) error {
 	d.rotation = rotation
 	madctl := uint8(0)
 	switch rotation % 4 {
@@ -384,23 +412,23 @@ func (d *Device) SetRotation(rotation drivers.Rotation) error {
 }
 
 // Command sends a command to the display
-func (d *Device) Command(command uint8) {
+func (d *DeviceOf[T]) Command(command uint8) {
 	d.Tx([]byte{command}, true)
 }
 
 // Command sends a data to the display
-func (d *Device) Data(data uint8) {
+func (d *DeviceOf[T]) Data(data uint8) {
 	d.Tx([]byte{data}, false)
 }
 
 // Tx sends data to the display
-func (d *Device) Tx(data []byte, isCommand bool) {
+func (d *DeviceOf[T]) Tx(data []byte, isCommand bool) {
 	d.dcPin.Set(!isCommand)
 	d.bus.Tx(data, nil)
 }
 
 // Size returns the current size of the display.
-func (d *Device) Size() (w, h int16) {
+func (d *DeviceOf[T]) Size() (w, h int16) {
 	if d.rotation == drivers.Rotation0 || d.rotation == drivers.Rotation180 {
 		return d.width, d.height
 	}
@@ -408,7 +436,7 @@ func (d *Device) Size() (w, h int16) {
 }
 
 // EnableBacklight enables or disables the backlight
-func (d *Device) EnableBacklight(enable bool) {
+func (d *DeviceOf[T]) EnableBacklight(enable bool) {
 	if enable {
 		d.blPin.High()
 	} else {
@@ -419,7 +447,7 @@ func (d *Device) EnableBacklight(enable bool) {
 // Set the sleep mode for this LCD panel. When sleeping, the panel uses a lot
 // less power. The LCD won't display an image anymore, but the memory contents
 // will be kept.
-func (d *Device) Sleep(sleepEnabled bool) error {
+func (d *DeviceOf[T]) Sleep(sleepEnabled bool) error {
 	if sleepEnabled {
 		// Shut down LCD panel.
 		d.Command(SLPIN)
@@ -435,7 +463,7 @@ func (d *Device) Sleep(sleepEnabled bool) error {
 }
 
 // InverColors inverts the colors of the screen
-func (d *Device) InvertColors(invert bool) {
+func (d *DeviceOf[T]) InvertColors(invert bool) {
 	if invert {
 		d.Command(INVON)
 	} else {
@@ -444,14 +472,6 @@ func (d *Device) InvertColors(invert bool) {
 }
 
 // IsBGR changes the color mode (RGB/BGR)
-func (d *Device) IsBGR(bgr bool) {
+func (d *DeviceOf[T]) IsBGR(bgr bool) {
 	d.isBGR = bgr
 }
-
-// RGBATo565 converts a color.RGBA to uint16 used in the display
-func RGBATo565(c color.RGBA) uint16 {
-	r, g, b, _ := c.RGBA()
-	return uint16((r & 0xF800) +
-		((g & 0xFC00) >> 5) +
-		((b & 0xF800) >> 11))
-}

st7789/st7789.go

@@ -14,6 +14,7 @@ import (
 	"errors"
 
 	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/pixel"
 )
 
 // Rotation controls the rotation used by the display.
@@ -24,6 +25,13 @@ type Rotation = drivers.Rotation
 // The color format used on the display, like RGB565, RGB666, and RGB444.
 type ColorFormat uint8
 
+// Pixel formats supported by the st7789 driver.
+type Color interface {
+	pixel.RGB444BE | pixel.RGB565BE
+
+	pixel.BaseColor
+}
+
 // FrameRate controls the frame rate used by the display.
 type FrameRate uint8
 
@@ -32,7 +40,11 @@ var (
 )
 
 // Device wraps an SPI connection.
-type Device struct {
+type Device = DeviceOf[pixel.RGB565BE]
+
+// DeviceOf is a generic version of Device. It supports multiple different pixel
+// formats.
+type DeviceOf[T Color] struct {
 	bus             drivers.SPI
 	dcPin           machine.Pin
 	resetPin        machine.Pin
@@ -47,6 +59,7 @@ type Device struct {
 	rotation        drivers.Rotation
 	frameRate       FrameRate
 	batchLength     int32
+	batchData       pixel.Image[T] // "image" with (width, height) of (batchLength, 1)
 	isBGR           bool
 	vSyncLines      int16
 	cmdBuf          [1]byte
@@ -71,11 +84,17 @@ type Config struct {
 
 // New creates a new ST7789 connection. The SPI wire must already be configured.
 func New(bus drivers.SPI, resetPin, dcPin, csPin, blPin machine.Pin) Device {
+	return NewOf[pixel.RGB565BE](bus, resetPin, dcPin, csPin, blPin)
+}
+
+// NewOf creates a new ST7789 connection with a particular pixel format. The SPI
+// wire must already be configured.
+func NewOf[T Color](bus drivers.SPI, resetPin, dcPin, csPin, blPin machine.Pin) DeviceOf[T] {
 	dcPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	resetPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	csPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	blPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
-	return Device{
+	return DeviceOf[T]{
 		bus:      bus,
 		dcPin:    dcPin,
 		resetPin: resetPin,
@@ -85,7 +104,7 @@ func New(bus drivers.SPI, resetPin, dcPin, csPin, blPin machine.Pin) Device {
 }
 
 // Configure initializes the display with default configuration
-func (d *Device) Configure(cfg Config) {
+func (d *DeviceOf[T]) Configure(cfg Config) {
 	if cfg.Width != 0 {
 		d.width = cfg.Width
 	} else {
@@ -137,7 +156,14 @@ func (d *Device) Configure(cfg Config) {
 	d.sendCommand(SLPOUT, nil) // Exit sleep mode
 
 	// Memory initialization
-	d.setColorFormat(ColorRGB565) // Set color mode to 16-bit color
+	var zeroColor T
+	switch any(zeroColor).(type) {
+	case pixel.RGB444BE:
+		d.setColorFormat(ColorRGB444) // 12 bits per pixel
+	default:
+		// Use default RGB565 color format.
+		d.setColorFormat(ColorRGB565) // 16 bits per pixel
+	}
 	time.Sleep(10 * time.Millisecond)
 
 	d.setRotation(d.rotation) // Memory orientation
@@ -189,7 +215,7 @@ func (d *Device) Configure(cfg Config) {
 // Send a command with data to the display. It does not change the chip select
 // pin (it must be low when calling). The DC pin is left high after return,
 // meaning that data can be sent right away.
-func (d *Device) sendCommand(command uint8, data []byte) error {
+func (d *DeviceOf[T]) sendCommand(command uint8, data []byte) error {
 	d.cmdBuf[0] = command
 	d.dcPin.Low()
 	err := d.bus.Tx(d.cmdBuf[:1], nil)
@@ -202,7 +228,7 @@ func (d *Device) sendCommand(command uint8, data []byte) error {
 
 // startWrite must be called at the beginning of all exported methods to set the
 // chip select pin low.
-func (d *Device) startWrite() {
+func (d *DeviceOf[T]) startWrite() {
 	if d.csPin != machine.NoPin {
 		d.csPin.Low()
 	}
@@ -210,14 +236,23 @@ func (d *Device) startWrite() {
 
 // endWrite must be called at the end of all exported methods to set the chip
 // select pin high.
-func (d *Device) endWrite() {
+func (d *DeviceOf[T]) endWrite() {
 	if d.csPin != machine.NoPin {
 		d.csPin.High()
 	}
 }
 
+// getBuffer returns the image buffer, that's always d.batchLength wide and 1
+// pixel high. It can be used as a temporary buffer to transmit image data.
+func (d *DeviceOf[T]) getBuffer() pixel.Image[T] {
+	if d.batchData.Len() == 0 {
+		d.batchData = pixel.NewImage[T](int(d.batchLength), 1)
+	}
+	return d.batchData
+}
+
 // Sync waits for the display to hit the next VSYNC pause
-func (d *Device) Sync() {
+func (d *DeviceOf[T]) Sync() {
 	d.SyncToScanLine(0)
 }
 
@@ -232,7 +267,7 @@ func (d *Device) Sync() {
 // NOTE: Use GetHighestScanLine and GetLowestScanLine to obtain the highest
 // and lowest useful values. Values are affected by front and back porch
 // vsync settings (derived from VSyncLines configuration option).
-func (d *Device) SyncToScanLine(scanline uint16) {
+func (d *DeviceOf[T]) SyncToScanLine(scanline uint16) {
 	scan := d.GetScanLine()
 
 	// Sometimes GetScanLine returns erroneous 0 on first call after draw, so double check
@@ -262,7 +297,7 @@ func (d *Device) SyncToScanLine(scanline uint16) {
 }
 
 // GetScanLine reads the current scanline value from the display
-func (d *Device) GetScanLine() uint16 {
+func (d *DeviceOf[T]) GetScanLine() uint16 {
 	d.startWrite()
 	data := []uint8{0x00, 0x00}
 	d.dcPin.Low()
@@ -277,24 +312,24 @@ func (d *Device) GetScanLine() uint16 {
 }
 
 // GetHighestScanLine calculates the last scanline id in the frame before VSYNC pause
-func (d *Device) GetHighestScanLine() uint16 {
+func (d *DeviceOf[T]) GetHighestScanLine() uint16 {
 	// Last scanline id appears to be backporch/2 + 320/2
 	return uint16(math.Ceil(float64(d.vSyncLines)/2)/2) + 160
 }
 
 // GetLowestScanLine calculate the first scanline id to appear after VSYNC pause
-func (d *Device) GetLowestScanLine() uint16 {
+func (d *DeviceOf[T]) GetLowestScanLine() uint16 {
 	// First scanline id appears to be backporch/2 + 1
 	return uint16(math.Ceil(float64(d.vSyncLines)/2)/2) + 1
 }
 
 // Display does nothing, there's no buffer as it might be too big for some boards
-func (d *Device) Display() error {
+func (d *DeviceOf[T]) Display() error {
 	return nil
 }
 
 // SetPixel sets a pixel in the screen
-func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
+func (d *DeviceOf[T]) SetPixel(x int16, y int16, c color.RGBA) {
 	if x < 0 || y < 0 ||
 		(((d.rotation == drivers.Rotation0 || d.rotation == drivers.Rotation180) && (x >= d.width || y >= d.height)) ||
 			((d.rotation == drivers.Rotation90 || d.rotation == drivers.Rotation270) && (x >= d.height || y >= d.width))) {
@@ -304,7 +339,7 @@ func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
 }
 
 // setWindow prepares the screen to be modified at a given rectangle
-func (d *Device) setWindow(x, y, w, h int16) {
+func (d *DeviceOf[T]) setWindow(x, y, w, h int16) {
 	x += d.columnOffset
 	y += d.rowOffset
 	copy(d.buf[:4], []uint8{uint8(x >> 8), uint8(x), uint8((x + w - 1) >> 8), uint8(x + w - 1)})
@@ -315,45 +350,41 @@ func (d *Device) setWindow(x, y, w, h int16) {
 }
 
 // FillRectangle fills a rectangle at a given coordinates with a color
-func (d *Device) FillRectangle(x, y, width, height int16, c color.RGBA) error {
+func (d *DeviceOf[T]) FillRectangle(x, y, width, height int16, c color.RGBA) error {
 	d.startWrite()
 	err := d.fillRectangle(x, y, width, height, c)
 	d.endWrite()
 	return err
 }
 
-func (d *Device) fillRectangle(x, y, width, height int16, c color.RGBA) error {
+func (d *DeviceOf[T]) fillRectangle(x, y, width, height int16, c color.RGBA) error {
 	k, i := d.Size()
 	if x < 0 || y < 0 || width <= 0 || height <= 0 ||
 		x >= k || (x+width) > k || y >= i || (y+height) > i {
 		return errors.New("rectangle coordinates outside display area")
 	}
 	d.setWindow(x, y, width, height)
-	c565 := RGBATo565(c)
-	c1 := uint8(c565 >> 8)
-	c2 := uint8(c565)
 
-	data := make([]uint8, d.batchLength*2)
-	for i := int32(0); i < d.batchLength; i++ {
-		data[i*2] = c1
-		data[i*2+1] = c2
-	}
-	j := int32(width) * int32(height)
+	image := d.getBuffer()
+	image.FillSolidColor(pixel.NewColor[T](c.R, c.G, c.B))
+	j := int(width) * int(height)
 	for j > 0 {
 		// The DC pin is already set to data in the setWindow call, so we can
 		// just write bytes on the SPI bus.
-		if j >= d.batchLength {
-			d.bus.Tx(data, nil)
+		if j >= image.Len() {
+			d.bus.Tx(image.RawBuffer(), nil)
 		} else {
-			d.bus.Tx(data[:j*2], nil)
+			d.bus.Tx(image.Rescale(j, 1).RawBuffer(), nil)
 		}
-		j -= d.batchLength
+		j -= image.Len()
 	}
 	return nil
 }
 
 // DrawRGBBitmap8 copies an RGB bitmap to the internal buffer at given coordinates
-func (d *Device) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
+//
+// Deprecated: use DrawBitmap instead.
+func (d *DeviceOf[T]) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
 	k, i := d.Size()
 	if x < 0 || y < 0 || w <= 0 || h <= 0 ||
 		x >= k || (x+w) > k || y >= i || (y+h) > i {
@@ -366,8 +397,15 @@ func (d *Device) DrawRGBBitmap8(x, y int16, data []uint8, w, h int16) error {
 	return nil
 }
 
+// DrawBitmap copies the bitmap to the internal buffer on the screen at the
+// given coordinates. It returns once the image data has been sent completely.
+func (d *DeviceOf[T]) DrawBitmap(x, y int16, bitmap pixel.Image[T]) error {
+	width, height := bitmap.Size()
+	return d.DrawRGBBitmap8(x, y, bitmap.RawBuffer(), int16(width), int16(height))
+}
+
 // FillRectangleWithBuffer fills buffer with a rectangle at a given coordinates.
-func (d *Device) FillRectangleWithBuffer(x, y, width, height int16, buffer []color.RGBA) error {
+func (d *DeviceOf[T]) FillRectangleWithBuffer(x, y, width, height int16, buffer []color.RGBA) error {
 	i, j := d.Size()
 	if x < 0 || y < 0 || width <= 0 || height <= 0 ||
 		x >= i || (x+width) > i || y >= j || (y+height) > j {
@@ -379,35 +417,32 @@ func (d *Device) FillRectangleWithBuffer(x, y, width, height int16, buffer []col
 	d.startWrite()
 	d.setWindow(x, y, width, height)
 
-	k := int32(width) * int32(height)
-	data := make([]uint8, d.batchLength*2)
-	offset := int32(0)
+	k := int(width) * int(height)
+	image := d.getBuffer()
+	offset := 0
 	for k > 0 {
-		for i := int32(0); i < d.batchLength; i++ {
-			if offset+i < int32(len(buffer)) {
-				c565 := RGBATo565(buffer[offset+i])
-				c1 := uint8(c565 >> 8)
-				c2 := uint8(c565)
-				data[i*2] = c1
-				data[i*2+1] = c2
+		for i := 0; i < image.Len(); i++ {
+			if offset+i < len(buffer) {
+				c := buffer[offset+i]
+				image.Set(i, 0, pixel.NewColor[T](c.R, c.G, c.B))
 			}
 		}
 		// The DC pin is already set to data in the setWindow call, so we don't
 		// have to set it here.
-		if k >= d.batchLength {
-			d.bus.Tx(data, nil)
+		if k >= image.Len() {
+			d.bus.Tx(image.RawBuffer(), nil)
 		} else {
-			d.bus.Tx(data[:k*2], nil)
+			d.bus.Tx(image.Rescale(k, 1).RawBuffer(), nil)
 		}
-		k -= d.batchLength
-		offset += d.batchLength
+		k -= image.Len()
+		offset += image.Len()
 	}
 	d.endWrite()
 	return nil
 }
 
 // DrawFastVLine draws a vertical line faster than using SetPixel
-func (d *Device) DrawFastVLine(x, y0, y1 int16, c color.RGBA) {
+func (d *DeviceOf[T]) DrawFastVLine(x, y0, y1 int16, c color.RGBA) {
 	if y0 > y1 {
 		y0, y1 = y1, y0
 	}
@@ -415,7 +450,7 @@ func (d *Device) DrawFastVLine(x, y0, y1 int16, c color.RGBA) {
 }
 
 // DrawFastHLine draws a horizontal line faster than using SetPixel
-func (d *Device) DrawFastHLine(x0, x1, y int16, c color.RGBA) {
+func (d *DeviceOf[T]) DrawFastHLine(x0, x1, y int16, c color.RGBA) {
 	if x0 > x1 {
 		x0, x1 = x1, x0
 	}
@@ -423,13 +458,13 @@ func (d *Device) DrawFastHLine(x0, x1, y int16, c color.RGBA) {
 }
 
 // FillScreen fills the screen with a given color
-func (d *Device) FillScreen(c color.RGBA) {
+func (d *DeviceOf[T]) FillScreen(c color.RGBA) {
 	d.startWrite()
 	d.fillScreen(c)
 	d.endWrite()
 }
 
-func (d *Device) fillScreen(c color.RGBA) {
+func (d *DeviceOf[T]) fillScreen(c color.RGBA) {
 	if d.rotation == NO_ROTATION || d.rotation == ROTATION_180 {
 		d.fillRectangle(0, 0, d.width, d.height, c)
 	} else {
@@ -441,13 +476,13 @@ func (d *Device) fillScreen(c color.RGBA) {
 // The default is RGB565, setting it to any other value will break functions
 // like SetPixel, FillRectangle, etc. Instead, you can write color data in the
 // specified color format using DrawRGBBitmap8.
-func (d *Device) SetColorFormat(format ColorFormat) {
+func (d *DeviceOf[T]) SetColorFormat(format ColorFormat) {
 	d.startWrite()
 	d.setColorFormat(format)
 	d.endWrite()
 }
 
-func (d *Device) setColorFormat(format ColorFormat) {
+func (d *DeviceOf[T]) setColorFormat(format ColorFormat) {
 	// Lower 4 bits set the color format used in SPI.
 	// Upper 4 bits set the color format used in the direct RGB interface.
 	// The RGB interface is not currently supported, so it is left at a
@@ -457,12 +492,12 @@ func (d *Device) setColorFormat(format ColorFormat) {
 }
 
 // Rotation returns the current rotation of the device.
-func (d *Device) Rotation() drivers.Rotation {
+func (d *DeviceOf[T]) Rotation() drivers.Rotation {
 	return d.rotation
 }
 
 // SetRotation changes the rotation of the device (clock-wise)
-func (d *Device) SetRotation(rotation Rotation) error {
+func (d *DeviceOf[T]) SetRotation(rotation Rotation) error {
 	d.rotation = rotation
 	d.startWrite()
 	err := d.setRotation(rotation)
@@ -470,24 +505,24 @@ func (d *Device) SetRotation(rotation Rotation) error {
 	return err
 }
 
-func (d *Device) setRotation(rotation Rotation) error {
+func (d *DeviceOf[T]) setRotation(rotation Rotation) error {
 	madctl := uint8(0)
 	switch rotation % 4 {
 	case drivers.Rotation0:
-		madctl = MADCTL_MX | MADCTL_MY
-		d.rowOffset = d.rowOffsetCfg
-		d.columnOffset = d.columnOffsetCfg
-	case drivers.Rotation90:
-		madctl = MADCTL_MY | MADCTL_MV
-		d.rowOffset = d.columnOffsetCfg
-		d.columnOffset = d.rowOffsetCfg
-	case drivers.Rotation180:
 		d.rowOffset = 0
 		d.columnOffset = 0
-	case drivers.Rotation270:
+	case drivers.Rotation90:
 		madctl = MADCTL_MX | MADCTL_MV
 		d.rowOffset = 0
 		d.columnOffset = 0
+	case drivers.Rotation180:
+		madctl = MADCTL_MX | MADCTL_MY
+		d.rowOffset = d.rowOffsetCfg
+		d.columnOffset = d.columnOffsetCfg
+	case drivers.Rotation270:
+		madctl = MADCTL_MY | MADCTL_MV
+		d.rowOffset = d.columnOffsetCfg
+		d.columnOffset = d.rowOffsetCfg
 	}
 	if d.isBGR {
 		madctl |= MADCTL_BGR
@@ -496,7 +531,7 @@ func (d *Device) setRotation(rotation Rotation) error {
 }
 
 // Size returns the current size of the display.
-func (d *Device) Size() (w, h int16) {
+func (d *DeviceOf[T]) Size() (w, h int16) {
 	if d.rotation == drivers.Rotation0 || d.rotation == drivers.Rotation180 {
 		return d.width, d.height
 	}
@@ -504,7 +539,7 @@ func (d *Device) Size() (w, h int16) {
 }
 
 // EnableBacklight enables or disables the backlight
-func (d *Device) EnableBacklight(enable bool) {
+func (d *DeviceOf[T]) EnableBacklight(enable bool) {
 	if enable {
 		d.blPin.High()
 	} else {
@@ -515,7 +550,7 @@ func (d *Device) EnableBacklight(enable bool) {
 // Set the sleep mode for this LCD panel. When sleeping, the panel uses a lot
 // less power. The LCD won't display an image anymore, but the memory contents
 // will be kept.
-func (d *Device) Sleep(sleepEnabled bool) error {
+func (d *DeviceOf[T]) Sleep(sleepEnabled bool) error {
 	if sleepEnabled {
 		d.startWrite()
 		d.sendCommand(SLPIN, nil)
@@ -537,7 +572,7 @@ func (d *Device) Sleep(sleepEnabled bool) error {
 }
 
 // InvertColors inverts the colors of the screen
-func (d *Device) InvertColors(invert bool) {
+func (d *DeviceOf[T]) InvertColors(invert bool) {
 	d.startWrite()
 	if invert {
 		d.sendCommand(INVON, nil)
@@ -548,15 +583,28 @@ func (d *Device) InvertColors(invert bool) {
 }
 
 // IsBGR changes the color mode (RGB/BGR)
-func (d *Device) IsBGR(bgr bool) {
+func (d *DeviceOf[T]) IsBGR(bgr bool) {
 	d.isBGR = bgr
 }
 
 // SetScrollArea sets an area to scroll with fixed top and bottom parts of the display.
-func (d *Device) SetScrollArea(topFixedArea, bottomFixedArea int16) {
+func (d *DeviceOf[T]) SetScrollArea(topFixedArea, bottomFixedArea int16) {
+	if d.height < 320 {
+		// The screen doesn't use the full 320 pixel height.
+		// Enlarge the bottom fixed area to fill the 320 pixel height, so that
+		// bottomFixedArea starts from the visible bottom of the screen.
+		topFixedArea += d.rowOffset
+		bottomFixedArea += (320 - d.height) - d.rowOffset
+	}
+	if d.rotation == drivers.Rotation180 {
+		// The screen is rotated by 180°, so we have to switch the top and
+		// bottom fixed area.
+		topFixedArea, bottomFixedArea = bottomFixedArea, topFixedArea
+	}
+	verticalScrollArea := 320 - topFixedArea - bottomFixedArea
 	copy(d.buf[:6], []uint8{
 		uint8(topFixedArea >> 8), uint8(topFixedArea),
-		uint8(d.height - topFixedArea - bottomFixedArea>>8), uint8(d.height - topFixedArea - bottomFixedArea),
+		uint8(verticalScrollArea >> 8), uint8(verticalScrollArea),
 		uint8(bottomFixedArea >> 8), uint8(bottomFixedArea)})
 	d.startWrite()
 	d.sendCommand(VSCRDEF, d.buf[:6])
@@ -564,7 +612,12 @@ func (d *Device) SetScrollArea(topFixedArea, bottomFixedArea int16) {
 }
 
 // SetScroll sets the vertical scroll address of the display.
-func (d *Device) SetScroll(line int16) {
+func (d *DeviceOf[T]) SetScroll(line int16) {
+	if d.rotation == drivers.Rotation180 {
+		// The screen is rotated by 180°, so we have to invert the scroll line
+		// (taking care of the RowOffset).
+		line = (319 - d.rowOffset) - line
+	}
 	d.buf[0] = uint8(line >> 8)
 	d.buf[1] = uint8(line)
 	d.startWrite()
@@ -573,16 +626,8 @@ func (d *Device) SetScroll(line int16) {
 }
 
 // StopScroll returns the display to its normal state.
-func (d *Device) StopScroll() {
+func (d *DeviceOf[T]) StopScroll() {
 	d.startWrite()
 	d.sendCommand(NORON, nil)
 	d.endWrite()
 }
-
-// RGBATo565 converts a color.RGBA to uint16 used in the display
-func RGBATo565(c color.RGBA) uint16 {
-	r, g, b, _ := c.RGBA()
-	return uint16((r & 0xF800) +
-		((g & 0xFC00) >> 5) +
-		((b & 0xF800) >> 11))
-}

tester/device.go

@@ -5,10 +5,10 @@ const MaxRegisters = 255
 
 type I2CDevice interface {
 	// ReadRegister implements I2C.ReadRegister.
-	ReadRegister(r uint8, buf []byte) error
+	readRegister(r uint8, buf []byte) error
 
 	// WriteRegister implements I2C.WriteRegister.
-	WriteRegister(r uint8, buf []byte) error
+	writeRegister(r uint8, buf []byte) error
 
 	// Tx implements I2C.Tx
 	Tx(w, r []byte) error

tester/device16.go

@@ -33,7 +33,7 @@ func (d *I2CDevice16) Addr() uint8 {
 }
 
 // ReadRegister implements I2C.ReadRegister.
-func (d *I2CDevice16) ReadRegister(r uint8, buf []byte) error {
+func (d *I2CDevice16) readRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
@@ -54,7 +54,7 @@ func (d *I2CDevice16) ReadRegister(r uint8, buf []byte) error {
 }
 
 // WriteRegister implements I2C.WriteRegister.
-func (d *I2CDevice16) WriteRegister(r uint8, buf []byte) error {
+func (d *I2CDevice16) writeRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
@@ -75,6 +75,16 @@ func (d *I2CDevice16) WriteRegister(r uint8, buf []byte) error {
 
 // Tx implements I2C.Tx.
 func (bus *I2CDevice16) Tx(w, r []byte) error {
-	// TODO: implement this
-	return nil
+	switch len(w) {
+	case 0:
+		bus.c.Fatalf("i2c mock: need a write byte")
+		return nil
+	case 1:
+		return bus.readRegister(w[0], r)
+	default:
+		if len(r) > 0 || len(w) == 1 {
+			bus.c.Fatalf("i2c mock: unsupported lengths in Tx(%d, %d)", len(w), len(r))
+		}
+		return bus.writeRegister(w[0], w[1:])
+	}
 }

tester/device8.go

@@ -34,17 +34,20 @@ func (d *I2CDevice8) Addr() uint8 {
 }
 
 // ReadRegister implements I2C.ReadRegister.
-func (d *I2CDevice8) ReadRegister(r uint8, buf []byte) error {
+func (d *I2CDevice8) readRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
+	if len(buf) == 0 {
+		d.c.Fatalf("no register buffer to read into")
+	}
 	d.assertRegisterRange(r, buf)
 	copy(buf, d.Registers[r:])
 	return nil
 }
 
 // WriteRegister implements I2C.WriteRegister.
-func (d *I2CDevice8) WriteRegister(r uint8, buf []byte) error {
+func (d *I2CDevice8) writeRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
@@ -55,8 +58,18 @@ func (d *I2CDevice8) WriteRegister(r uint8, buf []byte) error {
 
 // Tx implements I2C.Tx.
 func (bus *I2CDevice8) Tx(w, r []byte) error {
-	// TODO: implement this
-	return nil
+	switch len(w) {
+	case 0:
+		bus.c.Fatalf("i2c mock: need a write byte")
+		return nil
+	case 1:
+		return bus.readRegister(w[0], r)
+	default:
+		if len(r) > 0 || len(w) == 1 {
+			bus.c.Fatalf("i2c mock: unsupported lengths in Tx(%d, %d)", len(w), len(r))
+		}
+		return bus.writeRegister(w[0], w[1:])
+	}
 }
 
 // assertRegisterRange asserts that reading or writing the given

tester/devicecmd.go

@@ -50,7 +50,7 @@ func (d *I2CDeviceCmd) Addr() uint8 {
 }
 
 // ReadRegister implements I2C.ReadRegister.
-func (d *I2CDeviceCmd) ReadRegister(r uint8, buf []byte) error {
+func (d *I2CDeviceCmd) readRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}
@@ -59,7 +59,7 @@ func (d *I2CDeviceCmd) ReadRegister(r uint8, buf []byte) error {
 }
 
 // WriteRegister implements I2C.WriteRegister.
-func (d *I2CDeviceCmd) WriteRegister(r uint8, buf []byte) error {
+func (d *I2CDeviceCmd) writeRegister(r uint8, buf []byte) error {
 	if d.Err != nil {
 		return d.Err
 	}

tester/i2c.go

@@ -38,12 +38,12 @@ func (bus *I2CBus) NewDevice(addr uint8) *I2CDevice8 {
 
 // ReadRegister implements I2C.ReadRegister.
 func (bus *I2CBus) ReadRegister(addr uint8, r uint8, buf []byte) error {
-	return bus.FindDevice(addr).ReadRegister(r, buf)
+	return bus.FindDevice(addr).readRegister(r, buf)
 }
 
 // WriteRegister implements I2C.WriteRegister.
 func (bus *I2CBus) WriteRegister(addr uint8, r uint8, buf []byte) error {
-	return bus.FindDevice(addr).WriteRegister(r, buf)
+	return bus.FindDevice(addr).writeRegister(r, buf)
 }
 
 // Tx implements I2C.Tx.

tmp102/tmp102.go

@@ -4,7 +4,10 @@
 
 package tmp102 // import "tinygo.org/x/drivers/tmp102"
 
-import "tinygo.org/x/drivers"
+import (
+	"tinygo.org/x/drivers"
+	"tinygo.org/x/drivers/internal/legacy"
+)
 
 // Device holds the already configured I2C bus and the address of the sensor.
 type Device struct {
@@ -36,7 +39,7 @@ func (d *Device) Configure(cfg Config) {
 // Connected checks if the config register can be read and that the configuration is correct.
 func (d *Device) Connected() bool {
 	configData := make([]byte, 2)
-	err := d.bus.ReadRegister(d.address, RegConfiguration, configData)
+	err := legacy.ReadRegister(d.bus, d.address, RegConfiguration, configData)
 	// Check the reset configuration values.
 	if err != nil || configData[0] != 0x60 || configData[1] != 0xA0 {
 		return false
@@ -50,7 +53,7 @@ func (d *Device) ReadTemperature() (temperature int32, err error) {
 
 	tmpData := make([]byte, 2)
 
-	err = d.bus.ReadRegister(d.address, RegTemperature, tmpData)
+	err = legacy.ReadRegister(d.bus, d.address, RegTemperature, tmpData)
 
 	if err != nil {
 		return

version.go

@@ -2,4 +2,4 @@ package drivers
 
 // Version returns a user-readable string showing the version of the drivers package for support purposes.
 // Update this value before release of new version of software.
-const Version = "0.25.0"
+const Version = "0.26.0"

waveshare-epd/epd2in13/epd2in13.go

@@ -15,8 +15,8 @@ import (
 type Config struct {
 	Width        int16 // Width is the display resolution
 	Height       int16
-	LogicalWidth int16    // LogicalWidth must be a multiple of 8 and same size or bigger than Width
-	Rotation     Rotation // Rotation is clock-wise
+	LogicalWidth int16 // LogicalWidth must be a multiple of 8 and same size or bigger than Width
+	Rotation     drivers.Rotation
 }
 
 type Device struct {
@@ -30,10 +30,11 @@ type Device struct {
 	height       int16
 	buffer       []uint8
 	bufferLength uint32
-	rotation     Rotation
+	rotation     drivers.Rotation
 }
 
-type Rotation uint8
+// Deprecated: use drivers.Rotation instead.
+type Rotation = drivers.Rotation
 
 // Look up table for full updates
 var lutFullUpdate = [30]uint8{
@@ -130,6 +131,17 @@ func (d *Device) DeepSleep() {
 	d.WaitUntilIdle()
 }
 
+// Set the sleep mode of the panel. The display will still show its contents,
+// but will go into a lower-power state.
+func (d *Device) Sleep(sleepEnabled bool) error {
+	if sleepEnabled {
+		d.DeepSleep()
+	} else {
+		d.Reset()
+	}
+	return nil
+}
+
 // SendCommand sends a command to the display
 func (d *Device) SendCommand(command uint8) {
 	d.sendDataCommand(true, command)
@@ -167,18 +179,22 @@ func (d *Device) SetLUT(fullUpdate bool) {
 }
 
 // SetPixel modifies the internal buffer in a single pixel.
-// The display have 2 colors: black and white
-// We use RGBA(0,0,0, 255) as white (transparent)
-// Anything else as black
+// The display have 2 colors: black and white. We use a very simple cutoff to
+// determine whether a pixel is black or white (darker colors are black, lighter
+// colors are white).
 func (d *Device) SetPixel(x int16, y int16, c color.RGBA) {
 	x, y = d.xy(x, y)
 	if x < 0 || x >= d.logicalWidth || y < 0 || y >= d.height {
 		return
 	}
 	byteIndex := (x + y*d.logicalWidth) / 8
-	if c.R == 0 && c.G == 0 && c.B == 0 { // TRANSPARENT / WHITE
+	// Very simle black/white split.
+	// This isn't very accurate (especially for sRGB colors) but is close enough
+	// to the truth that it probably doesn't matter much - especially on an
+	// e-paper display.
+	if int(c.R)+int(c.G)+int(c.B) > 128*3 { // light, convert to white
 		d.buffer[byteIndex] |= 0x80 >> uint8(x%8)
-	} else { // WHITE / EMPTY
+	} else { // dark, convert to black
 		d.buffer[byteIndex] &^= 0x80 >> uint8(x%8)
 	}
 }
@@ -209,13 +225,13 @@ func (d *Device) DisplayRect(x int16, y int16, width int16, height int16) error
 	if x < 0 || y < 0 || x >= d.logicalWidth || y >= d.height || width < 0 || height < 0 {
 		return errors.New("wrong rectangle")
 	}
-	if d.rotation == ROTATION_90 {
+	if d.rotation == drivers.Rotation90 {
 		width, height = height, width
 		x -= width
-	} else if d.rotation == ROTATION_180 {
+	} else if d.rotation == drivers.Rotation180 {
 		x -= width - 1
 		y -= height - 1
-	} else if d.rotation == ROTATION_270 {
+	} else if d.rotation == drivers.Rotation270 {
 		width, height = height, width
 		y -= height
 	}
@@ -301,27 +317,33 @@ func (d *Device) ClearBuffer() {
 
 // Size returns the current size of the display.
 func (d *Device) Size() (w, h int16) {
-	if d.rotation == ROTATION_90 || d.rotation == ROTATION_270 {
+	if d.rotation == drivers.Rotation90 || d.rotation == drivers.Rotation270 {
 		return d.height, d.logicalWidth
 	}
 	return d.logicalWidth, d.height
 }
 
-// SetRotation changes the rotation (clock-wise) of the device
-func (d *Device) SetRotation(rotation Rotation) {
+// Rotation returns the current rotation of the device.
+func (d *Device) Rotation() drivers.Rotation {
+	return d.rotation
+}
+
+// SetRotation changes the rotation of the device.
+func (d *Device) SetRotation(rotation drivers.Rotation) error {
 	d.rotation = rotation
+	return nil
 }
 
 // xy chages the coordinates according to the rotation
 func (d *Device) xy(x, y int16) (int16, int16) {
 	switch d.rotation {
-	case NO_ROTATION:
+	case drivers.Rotation0:
 		return x, y
-	case ROTATION_90:
+	case drivers.Rotation90:
 		return d.width - y - 1, x
-	case ROTATION_180:
+	case drivers.Rotation180:
 		return d.width - x - 1, d.height - y - 1
-	case ROTATION_270:
+	case drivers.Rotation270:
 		return y, d.height - x - 1
 	}
 	return x, y

waveshare-epd/epd2in13/registers.go

@@ -1,5 +1,7 @@
 package epd2in13
 
+import "tinygo.org/x/drivers"
+
 // Registers
 const (
 	DRIVER_OUTPUT_CONTROL                = 0x01
@@ -24,8 +26,8 @@ const (
 	SET_RAM_Y_ADDRESS_COUNTER            = 0x4F
 	TERMINATE_FRAME_READ_WRITE           = 0xFF
 
-	NO_ROTATION  Rotation = 0
-	ROTATION_90  Rotation = 1 // 90 degrees clock-wise rotation
-	ROTATION_180 Rotation = 2
-	ROTATION_270 Rotation = 3
+	NO_ROTATION  = drivers.Rotation0
+	ROTATION_90  = drivers.Rotation90 // 90 degrees clock-wise rotation
+	ROTATION_180 = drivers.Rotation180
+	ROTATION_270 = drivers.Rotation270
 )