release: update changelog for v0.2.0

Signed-off-by: Ron Evans <ron@hybridgroup.com>

CHANGELOG.md

@@ -1,3 +1,11 @@
+0.2.0
+---
+- **new devices**
+    - AT24C32/64 2-wire serial EEPROM
+    - BME280 humidity/pressure sensor
+- **bugfixes**
+    - ws2812: better support for nrf52832
+
 0.1.0
 ---
 - **first release**

Makefile

@@ -11,6 +11,7 @@ smoke-test:
 	@mkdir -p build
 	tinygo build -size short -o ./build/test.elf -target=itsybitsy-m0 ./examples/adxl345/main.go
 	tinygo build -size short -o ./build/test.elf -target=itsybitsy-m0 ./examples/apa102/main.go
+	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/at24cx/main.go
 	tinygo build -size short -o ./build/test.elf -target=itsybitsy-m0 ./examples/bh1750/main.go
 	tinygo build -size short -o ./build/test.elf -target=itsybitsy-m0 ./examples/blinkm/main.go
 	tinygo build -size short -o ./build/test.elf -target=itsybitsy-m0 ./examples/bmp180/main.go
@@ -41,5 +42,6 @@ smoke-test:
 	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/waveshare-epd/epd2in13/main.go
 	tinygo build -size short -o ./build/test.elf -target=microbit ./examples/waveshare-epd/epd2in13x/main.go
 	tinygo build -size short -o ./build/test.elf -target=circuitplay-express ./examples/ws2812/main.go
+	tinygo build -size short -o ./build/test.elf -target=trinket-m0 ./examples/bme280/main.go
 
 test: clean fmt-check smoke-test

README.md

@@ -1,6 +1,6 @@
 # TinyGo Drivers
 
-[![GoDoc](https://godoc.org/github.com/tinygo-org/drivers?status.svg)](https://godoc.org/github.com/tinygo-org/drivers) [![CircleCI](https://circleci.com/gh/tinygo-org/drivers/tree/dev.svg?style=svg)](https://circleci.com/gh/tinygo-org/drivers/tree/dev)
+[![GoDoc](https://godoc.org/tinygo.org/x/drivers?status.svg)](https://godoc.org/tinygo.org/x/drivers) [![CircleCI](https://circleci.com/gh/tinygo-org/drivers/tree/dev.svg?style=svg)](https://circleci.com/gh/tinygo-org/drivers/tree/dev)
 
 
 This package provides a collection of hardware drivers for devices that can be used together with [TinyGo](https://tinygo.org).
@@ -56,8 +56,10 @@ func main() {
 |----------|-------------|
 | [ADXL345 accelerometer](http://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf) | I2C |
 | [APA102 RGB LED](https://cdn-shop.adafruit.com/product-files/2343/APA102C.pdf) | SPI |
+| [AT24CX 2-wire serial EEPROM](https://www.openimpulse.com/blog/wp-content/uploads/wpsc/downloadables/24C32-Datasheet.pdf) | I2C |
 | [BH1750 ambient light sensor](https://www.mouser.com/ds/2/348/bh1750fvi-e-186247.pdf) | I2C |
 | [BlinkM RGB LED](http://thingm.com/fileadmin/thingm/downloads/BlinkM_datasheet.pdf) | I2C |
+| [BME280 humidity/pressure sensor](https://cdn-shop.adafruit.com/datasheets/BST-BME280_DS001-10.pdf) | I2C |
 | [BMP180 barometer](https://cdn-shop.adafruit.com/datasheets/BST-BMP180-DS000-09.pdf) | I2C |
 | [DS1307 real time clock](https://datasheets.maximintegrated.com/en/ds/DS1307.pdf) | I2C |
 | [DS3231 real time clock](https://datasheets.maximintegrated.com/en/ds/DS3231.pdf) | I2C |

at24cx/at24cx.go

@@ -0,0 +1,171 @@
+// Package at24cx provides a driver for the AT24C32/64/128/256/512 2-wire serial EEPROM
+//
+// Datasheet:
+// https://www.openimpulse.com/blog/wp-content/uploads/wpsc/downloadables/24C32-Datasheet.pdf
+package at24cx // import "tinygo.org/x/drivers/at24cx"
+
+import (
+	"errors"
+	"machine"
+	"time"
+)
+
+// Device wraps an I2C connection to a DS3231 device.
+type Device struct {
+	bus               machine.I2C
+	Address           uint16
+	pageSize          uint16
+	currentRAMAddress uint16
+	startRAMAddress   uint16
+	endRAMAddress     uint16
+}
+
+type Config struct {
+	PageSize        uint16
+	StartRAMAddress uint16
+	EndRAMAddress   uint16
+}
+
+// New creates a new AT24C32/64 connection. The I2C bus must already be
+// configured.
+//
+// This function only creates the Device object, it does not touch the device.
+func New(bus machine.I2C) Device {
+	return Device{
+		bus:     bus,
+		Address: Address,
+	}
+}
+
+// Configure sets up the device for communication
+func (d *Device) Configure(cfg Config) {
+	if cfg.PageSize == 0 {
+		d.pageSize = 32
+	} else {
+		d.pageSize = cfg.PageSize
+	}
+	if cfg.EndRAMAddress == 0 {
+		d.endRAMAddress = 4096
+	} else {
+		d.endRAMAddress = cfg.EndRAMAddress
+	}
+	d.startRAMAddress = cfg.StartRAMAddress
+}
+
+// WriteByte writes a byte at the specified address
+func (d *Device) WriteByte(eepromAddress uint16, value uint8) error {
+	address := []uint8{
+		uint8((eepromAddress >> 8) & 0xFF),
+		uint8(eepromAddress & 0xFF),
+		value,
+	}
+	return d.bus.Tx(d.Address, address, nil)
+}
+
+// ReadByte reads the byte at the specified address
+func (d *Device) ReadByte(eepromAddress uint16) (uint8, error) {
+	address := []uint8{
+		uint8(eepromAddress >> 8),
+		uint8(eepromAddress & 0xFF),
+	}
+	data := make([]uint8, 1)
+	err := d.bus.Tx(d.Address, address, data)
+	return data[0], err
+}
+
+// WriteAt writes a byte array at the specified address
+func (d *Device) WriteAt(data []byte, offset int64) (n int, err error) {
+	return d.writeAt(data, uint16(offset))
+}
+
+// writeAt writes a byte array at the specified address
+func (d *Device) writeAt(data []byte, offset uint16) (n int, err error) {
+	values := make([]uint8, 32)
+	dataLeft := uint16(len(data))
+	d.currentRAMAddress = offset
+	offset = 0
+	var offsetPage uint16
+	var chunkLength uint16
+	for dataLeft > 0 {
+		offsetPage = d.currentRAMAddress % d.pageSize
+		if dataLeft < 30 { // The 32K/64K EEPROM is capable of 32-byte page writes and we're using 2 for the address
+			chunkLength = dataLeft
+		} else {
+			chunkLength = 30
+		}
+		if (d.pageSize - offsetPage) < chunkLength {
+			chunkLength = d.pageSize - offsetPage
+		}
+		for i := uint16(0); i < chunkLength; i++ {
+			values[2+i] = data[offset+i]
+		}
+		values[0] = uint8(d.currentRAMAddress >> 8)
+		values[1] = uint8(d.currentRAMAddress & 0xFF)
+		err := d.bus.Tx(d.Address, values[:chunkLength+2], nil)
+		if err != nil {
+			return 0, err
+		}
+		dataLeft -= chunkLength
+		offset += chunkLength
+		if d.endRAMAddress-chunkLength < d.currentRAMAddress {
+			d.currentRAMAddress = d.startRAMAddress + (d.currentRAMAddress+uint16(len(data)))%d.endRAMAddress
+		} else {
+			d.currentRAMAddress += chunkLength
+		}
+		time.Sleep(2 * time.Millisecond) // writing again too soon will block the device
+	}
+	return len(data), nil
+}
+
+// ReadAt reads the bytes at the specified address
+func (d *Device) ReadAt(data []byte, offset int64) (n int, err error) {
+	return d.readAt(data, uint16(offset))
+}
+
+// readAt reads the bytes at the specified address
+func (d *Device) readAt(data []byte, offset uint16) (n int, err error) {
+	address := []uint8{
+		uint8((offset >> 8) & 0xFF),
+		uint8(offset & 0xFF),
+	}
+	err = d.bus.Tx(d.Address, address, data)
+
+	if d.endRAMAddress-uint16(len(data)) < offset {
+		d.currentRAMAddress = d.startRAMAddress + (offset+uint16(len(data)))%d.endRAMAddress
+	} else {
+		d.currentRAMAddress = offset + uint16(len(data))
+	}
+	return len(data), err
+}
+
+// Seek sets the offset for the next Read or Write on SRAM to offset, interpreted
+// according to whence: 0 means relative to the origin of the SRAM, 1 means
+// relative to the current offset, and 2 means relative to the end.
+// returns new offset and error, if any
+func (d *Device) Seek(offset int64, whence int) (int64, error) {
+	w := uint16(0)
+	switch whence {
+	case 0:
+		w = d.startRAMAddress
+	case 1:
+		w = d.currentRAMAddress
+	case 2:
+		w = d.endRAMAddress
+	default:
+		return 0, errors.New("invalid whence")
+	}
+	d.currentRAMAddress = w + uint16(offset)
+	return int64(d.currentRAMAddress), nil
+}
+
+// Write writes len(data) bytes to SRAM
+// returns number of bytes written and error, if any
+func (d *Device) Write(data []byte) (n int, err error) {
+	return d.writeAt(data, d.currentRAMAddress)
+}
+
+// Read reads len(data) from SRAM
+// returns number of bytes written and error, if any
+func (d *Device) Read(data []uint8) (n int, err error) {
+	return d.readAt(data, d.currentRAMAddress)
+}

at24cx/registers.go

@@ -0,0 +1,4 @@
+package at24cx
+
+// The I2C address which this device listens to.
+const Address = 0x57

bme280/bme280.go

@@ -0,0 +1,257 @@
+// Package bme280 provides a driver for the BME280 digital combined
+// humidity and pressure sensor by Bosch.
+//
+// Datasheet:
+// https://cdn-shop.adafruit.com/datasheets/BST-BME280_DS001-10.pdf
+//
+package bme280
+
+import (
+	"machine"
+	"math"
+)
+
+// calibrationCoefficients reads at startup and stores the calibration coefficients
+type calibrationCoefficients struct {
+	t1 uint16
+	t2 int16
+	t3 int16
+	p1 uint16
+	p2 int16
+	p3 int16
+	p4 int16
+	p5 int16
+	p6 int16
+	p7 int16
+	p8 int16
+	p9 int16
+	h1 uint8
+	h2 int16
+	h3 uint8
+	h4 int16
+	h5 int16
+	h6 int8
+}
+
+// Device wraps an I2C connection to a BME280 device.
+type Device struct {
+	bus                     machine.I2C
+	Address                 uint16
+	calibrationCoefficients calibrationCoefficients
+}
+
+// New creates a new BME280 connection. The I2C bus must already be
+// configured.
+//
+// This function only creates the Device object, it does not touch the device.
+func New(bus machine.I2C) Device {
+	return Device{
+		bus:     bus,
+		Address: Address,
+	}
+}
+
+// Configure sets up the device for communication and
+// read the calibration coefficientes.
+func (d *Device) Configure() {
+
+	var data [24]byte
+	err := d.bus.ReadRegister(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[:])
+	if err != nil {
+		return
+	}
+
+	var h2lsb [7]byte
+	err = d.bus.ReadRegister(uint8(d.Address), REG_CALIBRATION_H2LSB, h2lsb[:])
+	if err != nil {
+		return
+	}
+
+	d.calibrationCoefficients.t1 = readUintLE(data[0], data[1])
+	d.calibrationCoefficients.t2 = readIntLE(data[2], data[3])
+	d.calibrationCoefficients.t3 = readIntLE(data[4], data[5])
+	d.calibrationCoefficients.p1 = readUintLE(data[6], data[7])
+	d.calibrationCoefficients.p2 = readIntLE(data[8], data[9])
+	d.calibrationCoefficients.p3 = readIntLE(data[10], data[11])
+	d.calibrationCoefficients.p4 = readIntLE(data[12], data[13])
+	d.calibrationCoefficients.p5 = readIntLE(data[14], data[15])
+	d.calibrationCoefficients.p6 = readIntLE(data[16], data[17])
+	d.calibrationCoefficients.p7 = readIntLE(data[18], data[19])
+	d.calibrationCoefficients.p8 = readIntLE(data[20], data[21])
+	d.calibrationCoefficients.p9 = readIntLE(data[22], data[23])
+
+	d.calibrationCoefficients.h1 = h1[0]
+	d.calibrationCoefficients.h2 = readIntLE(h2lsb[0], h2lsb[1])
+	d.calibrationCoefficients.h3 = h2lsb[2]
+	d.calibrationCoefficients.h6 = int8(h2lsb[6])
+	d.calibrationCoefficients.h4 = 0 + (int16(h2lsb[3]) << 4) | (int16(h2lsb[4] & 0x0F))
+	d.calibrationCoefficients.h5 = 0 + (int16(h2lsb[5]) << 4) | (int16(h2lsb[4]) >> 4)
+
+	d.bus.WriteRegister(uint8(d.Address), CTRL_HUMIDITY_ADDR, []byte{0x3f})
+	d.bus.WriteRegister(uint8(d.Address), CTRL_MEAS_ADDR, []byte{0xB7})
+	d.bus.WriteRegister(uint8(d.Address), CTRL_CONFIG, []byte{0x00})
+
+}
+
+// Connected returns whether a BME280 has been found.
+// 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)
+	return data[0] == CHIP_ID
+}
+
+// Reset the device
+func (d *Device) Reset() {
+	d.bus.WriteRegister(uint8(d.Address), CMD_RESET, []byte{0xB6})
+}
+
+// ReadTemperature returns the temperature in celsius milli degrees (ºC/1000)
+func (d *Device) ReadTemperature() (int32, error) {
+	data, err := d.readData()
+	if err != nil {
+		return 0, err
+	}
+
+	temp, _ := d.calculateTemp(data)
+	return temp, nil
+}
+
+// ReadPressure returns the pressure in milli pascals mPa
+func (d *Device) ReadPressure() (int32, error) {
+	data, err := d.readData()
+	if err != nil {
+		return 0, err
+	}
+	_, tFine := d.calculateTemp(data)
+	pressure := d.calculatePressure(data, tFine)
+	return pressure, nil
+}
+
+// ReadHumidity returns the relative humidity in hundredths of a percent
+func (d *Device) ReadHumidity() (int32, error) {
+	data, err := d.readData()
+	if err != nil {
+		return 0, err
+	}
+	_, tFine := d.calculateTemp(data)
+	humidity := d.calculateHumidity(data, tFine)
+	return humidity, nil
+}
+
+// ReadAltitude returns the current altitude in meters based on the
+// current barometric pressure and estimated pressure at sea level.
+// Calculation is based on code from Adafruit BME280 library
+// 	https://github.com/adafruit/Adafruit_BME280_Library
+func (d *Device) ReadAltitude() (alt int32, err error) {
+	mPa, _ := d.ReadPressure()
+	atmP := float32(mPa) / 100000
+	alt = int32(44330.0 * (1.0 - math.Pow(float64(atmP/SEALEVEL_PRESSURE), 0.1903)))
+	return
+}
+
+// convert2Bytes converts two bytes to int32
+func convert2Bytes(msb byte, lsb byte) int32 {
+	return int32(readUint(msb, lsb))
+}
+
+// convert3Bytes converts three bytes to int32
+func convert3Bytes(msb byte, b1 byte, lsb byte) int32 {
+	return int32(((((uint32(msb) << 8) | uint32(b1)) << 8) | uint32(lsb)) >> 4)
+}
+
+// readUint converts two bytes to uint16
+func readUint(msb byte, lsb byte) uint16 {
+	return (uint16(msb) << 8) | uint16(lsb)
+}
+
+// readUintLE converts two little endian bytes to uint16
+func readUintLE(msb byte, lsb byte) uint16 {
+	temp := readUint(msb, lsb)
+	return (temp >> 8) | (temp << 8)
+}
+
+// readIntLE converts two little endian bytes to int16
+func readIntLE(msb byte, lsb byte) int16 {
+	return int16(readUintLE(msb, lsb))
+}
+
+// readData does a burst read from 0xF7 to 0xF0 according to the datasheet
+// resulting in an slice with 8 bytes 0-2 = pressure / 3-5 = temperature / 6-7 = humidity
+func (d *Device) readData() (data [8]byte, err error) {
+	err = d.bus.ReadRegister(uint8(d.Address), REG_PRESSURE, data[:])
+	if err != nil {
+		println(err)
+		return
+	}
+	return
+}
+
+// calculateTemp uses the data slice and applies calibrations values on it to convert the value to milli degrees
+// it also calculates the variable tFine which is used by the pressure and humidity calculation
+func (d *Device) calculateTemp(data [8]byte) (int32, int32) {
+
+	rawTemp := convert3Bytes(data[3], data[4], data[5])
+
+	var1 := (((rawTemp >> 3) - (int32(d.calibrationCoefficients.t1) << 1)) * int32(d.calibrationCoefficients.t2)) >> 11
+	var2 := (((((rawTemp >> 4) - int32(d.calibrationCoefficients.t1)) * ((rawTemp >> 4) - int32(d.calibrationCoefficients.t1))) >> 12) * int32(d.calibrationCoefficients.t3)) >> 14
+
+	tFine := var1 + var2
+	T := (tFine*5 + 128) >> 8
+	return (10 * T), tFine
+}
+
+// calculatePressure uses the data slice and applies calibrations values on it to convert the value to milli pascals mPa
+func (d *Device) calculatePressure(data [8]byte, tFine int32) int32 {
+
+	rawPressure := convert3Bytes(data[0], data[1], data[2])
+
+	var1 := int64(tFine) - 128000
+	var2 := var1 * var1 * int64(d.calibrationCoefficients.p6)
+	var2 = var2 + ((var1 * int64(d.calibrationCoefficients.p5)) << 17)
+	var2 = var2 + (int64(d.calibrationCoefficients.p4) << 35)
+	var1 = ((var1 * var1 * int64(d.calibrationCoefficients.p3)) >> 8) + ((var1 * int64(d.calibrationCoefficients.p2)) << 12)
+	var1 = ((int64(1) << 47) + var1) * int64(d.calibrationCoefficients.p1) >> 33
+
+	if var1 == 0 {
+		return 0 // avoid exception caused by division by zero
+	}
+	p := int64(1048576 - rawPressure)
+	p = (((p << 31) - var2) * 3125) / var1
+	var1 = (int64(d.calibrationCoefficients.p9) * (p >> 13) * (p >> 13)) >> 25
+	var2 = (int64(d.calibrationCoefficients.p8) * p) >> 19
+
+	p = ((p + var1 + var2) >> 8) + (int64(d.calibrationCoefficients.p7) << 4)
+	p = (p / 256)
+	return int32(1000 * p)
+}
+
+// calculateHumidity uses the data slice and applies calibrations values on it to convert the value to relative humidity in hundredths of a percent
+func (d *Device) calculateHumidity(data [8]byte, tFine int32) int32 {
+
+	rawHumidity := convert2Bytes(data[6], data[7])
+
+	h := float32(tFine) - 76800
+
+	if h == 0 {
+		println("invalid value")
+	}
+
+	var1 := float32(rawHumidity) - (float32(d.calibrationCoefficients.h4)*64.0 +
+		(float32(d.calibrationCoefficients.h5) / 16384.0 * h))
+
+	var2 := float32(d.calibrationCoefficients.h2) / 65536.0 *
+		(1.0 + float32(d.calibrationCoefficients.h6)/67108864.0*h*
+			(1.0+float32(d.calibrationCoefficients.h3)/67108864.0*h))
+
+	h = var1 * var2
+	h = h * (1 - float32(d.calibrationCoefficients.h1)*h/524288)
+	return int32(100 * h)
+
+}

bme280/registers.go

@@ -0,0 +1,25 @@
+package bme280
+
+// Constants/addresses used for I2C.
+
+// The I2C address which this device listens to.
+const Address = 0x76
+
+// Registers. Names, addresses and comments copied from the datasheet.
+const (
+	CTRL_MEAS_ADDR        = 0xF4
+	CTRL_HUMIDITY_ADDR    = 0xF2
+	CTRL_CONFIG           = 0xF5
+	REG_PRESSURE          = 0xF7
+	REG_CALIBRATION       = 0x88
+	REG_CALIBRATION_H1    = 0xA1
+	REG_CALIBRATION_H2LSB = 0xE1
+	CMD_RESET             = 0xE0
+
+	WHO_AM_I = 0xD0
+	CHIP_ID  = 0x60
+)
+
+const (
+	SEALEVEL_PRESSURE float32 = 1013.25 // in hPa
+)

examples/at24cx/main.go

@@ -0,0 +1,122 @@
+package main
+
+import (
+	"machine"
+	"time"
+
+	"tinygo.org/x/drivers/at24cx"
+)
+
+func main() {
+	machine.I2C0.Configure(machine.I2CConfig{})
+
+	eeprom := at24cx.New(machine.I2C0)
+	eeprom.Configure(at24cx.Config{})
+
+	values := make([]uint8, 100)
+	for i := uint16(0); i < 100; i++ {
+		values[i] = uint8(65 + i%26)
+	}
+	_, err := eeprom.WriteAt(values, 0)
+	if err != nil {
+		println("There was an error in WriteAt:", err)
+		return
+	}
+
+	for i := uint16(0); i < 26; i++ {
+		err = eeprom.WriteByte(100+i, uint8(90-i))
+		if err != nil {
+			println("There was an error in WriteByte:", i, err)
+			return
+		}
+		time.Sleep(2 * time.Millisecond)
+	}
+
+	println("\n\r\n\rRead 26 bytes one by one from address 0")
+	println("Expected: ABCDEFGHIJKLMNOPQRSTUVWXYZ")
+	print("Real: ")
+	for i := uint16(0); i < 26; i++ {
+		char, err := eeprom.ReadByte(i)
+		print(string(char))
+		if err != nil {
+			println("There was an error in ReadByte:", i, err)
+			return
+		}
+	}
+	println("")
+
+	println("\n\r\n\rRead 100 bytes from address 26")
+	println("Expected: ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMNOPQRSTUVZYXWVUTSRQPONMLKJIHGFEDCBA")
+	print("Real: ")
+	data := make([]byte, 100)
+	_, err = eeprom.ReadAt(data, 26)
+	if err != nil {
+		println("There was an error in ReadAt:", err)
+		return
+	}
+	for i := 0; i < 100; i++ {
+		print(string(data[i]))
+	}
+	println("")
+
+	// Move to the beginning of memory
+	eeprom.Seek(0, 0)
+	_, err = eeprom.Write([]uint8{88, 88, 88})
+	if err != nil {
+		println("There was an error in Write:", err)
+		return
+	}
+
+	println("\n\r\n\rRead 3 bytes")
+	println("Expected: DEF")
+	print("Real: ")
+	data = make([]byte, 3)
+	_, err = eeprom.Read(data)
+	if err != nil {
+		println("There was an error in Read:", err)
+		return
+	}
+	for _, char := range data {
+		print(string(char))
+	}
+	println("")
+
+	println("\n\r\n\rRead another 3 bytes (from the beginning this time)")
+	eeprom.Seek(-6, 1)
+	println("Expected: XXX")
+	print("Real: ")
+	data = make([]byte, 3)
+	_, err = eeprom.Read(data)
+	if err != nil {
+		println("There was an error in Read:", err)
+		return
+	}
+	for _, char := range data {
+		print(string(char))
+	}
+	println("")
+
+	// Move to the end of memory
+	eeprom.Seek(-4, 2)
+	_, err = eeprom.Write([]uint8{89, 90, 89, 90})
+	if err != nil {
+		println("There was an error in Write:", err)
+		return
+	}
+
+	println("\n\r\n\rRead the last 4 bytes of the memory and the 3 of the beginning")
+	eeprom.Seek(-4, 1)
+	println("Expected: YZYZXXX")
+	print("Real: ")
+	data = make([]byte, 7)
+	_, err = eeprom.Read(data)
+	if err != nil {
+		println("There was an error in Read:", err)
+		return
+	}
+	for _, char := range data {
+		print(string(char))
+	}
+	println("")
+
+}

examples/bme280/main.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"machine"
+	"strconv"
+	"time"
+
+	"tinygo.org/x/drivers/bme280"
+)
+
+func main() {
+
+	machine.I2C0.Configure(machine.I2CConfig{})
+	sensor := bme280.New(machine.I2C0)
+	sensor.Configure()
+
+	connected := sensor.Connected()
+	if !connected {
+		println("BME280 not detected")
+	}
+	println("BME280 detected")
+
+	for {
+		temp, _ := sensor.ReadTemperature()
+		println("Temperature:", strconv.FormatFloat(float64(temp)/1000, 'f', 2, 64), "ºC")
+		press, _ := sensor.ReadPressure()
+		println("Pressure:", strconv.FormatFloat(float64(press)/100000, 'f', 2, 64), "hPa")
+		hum, _ := sensor.ReadHumidity()
+		println("Humidity:", strconv.FormatFloat(float64(hum)/100, 'f', 2, 64), "%")
+		alt, _ := sensor.ReadAltitude()
+		println("Altitude:", alt, "m")
+
+		time.Sleep(2 * time.Second)
+	}
+}

ws2812/ws2812_m4_64m.go

@@ -17,12 +17,12 @@ func (d Device) WriteByte(c byte) error {
 
 	// See:
 	// https://wp.josh.com/2014/05/13/ws2812-neopixels-are-not-so-finicky-once-you-get-to-know-them/
-	// T0H: 14-16 cycles or  218.75ns -  250.00ns
+	// T0H: 17-19 cycles or  265.63ns -  296.88ns
 	// T0L: 54-56 cycles or  843.75ns -  875.00ns
-	//   +: 68-72 cycles or 1062.50ns - 1125.00ns
-	// T1H: 36-38 cycles or  562.50ns -  593.75ns
+	//   +: 71-75 cycles or 1109.38ns - 1171.88ns
+	// T1H: 39-41 cycles or  609.38ns -  640.63ns
 	// T1L: 30-32 cycles or  468.75ns -  500.0ns
-	//   +: 66-70 cycles or 1031.25ns - 1093.75ns
+	//   +: 69-73 cycles or 1078.13ns - 1140.63ns
 	// A branch is treated here as 1-3 cycles, because apparently it might get
 	// speculated. This is more of a guess than hard fact, because the only docs
 	// by ARM that state this are now considered superseded (by what?).
@@ -41,6 +41,9 @@ func (d Device) WriteByte(c byte) error {
 		nop
 		nop
 		nop
+		nop
+		nop
+		nop
 		bcs.n skip_store               @ [1-3]
 		str   {maskClear}, {portClear} @ [2]   T0H -> T0L transition
 	skip_store: