mirror of
https://github.com/tinygo-org/drivers.git
synced 2026-07-26 10:38:41 +00:00
i2csoft: add support for software I2C
This commit is contained in:
sago35
Ron Evans
@@ -205,12 +205,14 @@ endif
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@md5sum ./build/test.hex
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tinygo build -size short -o ./build/test.hex -target=wioterminal ./examples/rtl8720dn/mqttsub/
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@md5sum ./build/test.hex
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tinygo build -size short -o ./build/test.hex -target=feather-m4 ./examples/i2csoft/adt7410/
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@md5sum ./build/test.hex
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DRIVERS = $(wildcard */)
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NOTESTS = build examples flash semihosting pcd8544 shiftregister st7789 microphone mcp3008 gps microbitmatrix \
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hcsr04 ssd1331 ws2812 thermistor apa102 easystepper ssd1351 ili9341 wifinina shifter hub75 \
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hd44780 buzzer ssd1306 espat l9110x st7735 bmi160 l293x dht keypad4x4 max72xx p1am tone tm1637 \
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pcf8563 mcp2515 servo sdcard rtl8720dn image cmd
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pcf8563 mcp2515 servo sdcard rtl8720dn image cmd i2csoft
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TESTS = $(filter-out $(addsuffix /%,$(NOTESTS)),$(DRIVERS))
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unit-test:
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@@ -80,6 +80,7 @@ The following 67 devices are supported.
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| [HC-SR04 Ultrasonic distance sensor](https://cdn.sparkfun.com/datasheets/Sensors/Proximity/HCSR04.pdf) | GPIO |
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| [HD44780 LCD controller](https://www.sparkfun.com/datasheets/LCD/HD44780.pdf) | GPIO/I2C |
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| [HUB75 RGB led matrix](https://cdn-learn.adafruit.com/downloads/pdf/32x16-32x32-rgb-led-matrix.pdf) | SPI |
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| [software I2C driver](https://www.ti.com/lit/an/slva704/slva704.pdf) | GPIO |
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| [ILI9341 TFT color display](https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf) | SPI |
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| [INA260 Volt/Amp/Power meter](https://www.ti.com/lit/ds/symlink/ina260.pdf) | I2C |
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| [4x4 Membrane Keypad](https://cdn.sparkfun.com/assets/f/f/a/5/0/DS-16038.pdf) | GPIO |
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@@ -0,0 +1,27 @@
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package main
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import (
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"fmt"
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"machine"
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"time"
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"tinygo.org/x/drivers/adt7410"
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"tinygo.org/x/drivers/i2csoft"
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)
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func main() {
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i2c := i2csoft.New(machine.SCL_PIN, machine.SDA_PIN)
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i2c.Configure(i2csoft.I2CConfig{
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Frequency: 400e3,
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})
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sensor := adt7410.New(i2c)
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sensor.Configure()
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for {
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temp := sensor.ReadTempF()
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fmt.Printf("temperature: %f\r\n", temp)
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time.Sleep(time.Second)
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}
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}
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@@ -0,0 +1,297 @@
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package i2csoft
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import (
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"errors"
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"machine"
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)
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// I2C is an I2C implementation by Software. Since it is implemented by
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// software, it can be used with microcontrollers that do not have I2C
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// function. This is not efficient but works around broken or missing drivers.
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type I2C struct {
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scl machine.Pin
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sda machine.Pin
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nack bool
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baudrate uint32
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}
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// I2CConfig is used to store config info for I2C.
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type I2CConfig struct {
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Frequency uint32
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SCL machine.Pin
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SDA machine.Pin
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}
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var (
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errSI2CAckExpected = errors.New("I2C error: expected ACK not NACK")
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)
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// New returns the i2csoft driver. For the arguments, specify the pins to be
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// used as SCL and SDA. As I2C is implemented in software, any GPIO pin can be
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// specified.
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func New(sclPin, sdaPin machine.Pin) *I2C {
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return &I2C{
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scl: sclPin,
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sda: sdaPin,
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baudrate: 100 * 1e3,
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}
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}
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// Configure is intended to setup the I2C interface.
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func (i2c *I2C) Configure(config I2CConfig) error {
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// Default I2C bus speed is 100 kHz.
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if config.Frequency != 0 {
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i2c.baudrate = config.Frequency
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}
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// This exists for compatibility with machine.I2CConfig. SCL and SDA must
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// be set at the same time. Because Pin(0) is sometimes set, it is not
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// checked for 0.
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if config.SCL != config.SDA {
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i2c.scl = config.SCL
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i2c.sda = config.SDA
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}
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i2c.SetBaudRate(config.Frequency)
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// enable pins
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i2c.sda.High()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinOutput})
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i2c.scl.High()
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i2c.scl.Configure(machine.PinConfig{Mode: machine.PinOutput})
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return nil
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}
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// SetBaudRate sets the communication speed for the I2C.
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func (i2c *I2C) SetBaudRate(br uint32) {
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i2c.baudrate = br
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}
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// Tx does a single I2C transaction at the specified address.
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// It clocks out the given address, writes the bytes in w, reads back len(r)
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// bytes and stores them in r, and generates a stop condition on the bus.
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func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
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var err error
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i2c.nack = false
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if len(w) != 0 {
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// send start/address for write
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i2c.sendAddress(addr, true)
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// wait until transmission complete
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// ACK received (0: ACK, 1: NACK)
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if i2c.nack {
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i2c.signalStop()
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return errSI2CAckExpected
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}
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// write data
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for _, b := range w {
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err = i2c.WriteByte(b)
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if err != nil {
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return err
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}
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}
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err = i2c.signalStop()
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if err != nil {
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return err
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}
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}
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if len(r) != 0 {
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// send start/address for read
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i2c.sendAddress(addr, false)
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// wait transmission complete
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// ACK received (0: ACK, 1: NACK)
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if i2c.nack {
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i2c.signalStop()
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return errSI2CAckExpected
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}
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// read first byte
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r[0] = i2c.readByte()
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for i := 1; i < len(r); i++ {
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// Send an ACK
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i2c.signalRead()
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// Read data and send the ACK
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r[i] = i2c.readByte()
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}
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// Send NACK to end transmission
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i2c.sendNack()
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err = i2c.signalStop()
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if err != nil {
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return err
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}
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}
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return nil
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}
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// WriteByte writes a single byte to the I2C bus.
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func (i2c *I2C) WriteByte(data byte) error {
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// Send data byte
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i2c.scl.Low()
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i2c.sda.High()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinOutput})
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i2c.wait()
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for i := 0; i < 8; i++ {
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i2c.scl.Low()
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if ((data >> (7 - i)) & 1) == 1 {
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i2c.sda.High()
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} else {
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i2c.sda.Low()
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}
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i2c.wait()
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i2c.wait()
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i2c.scl.High()
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i2c.wait()
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i2c.wait()
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}
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i2c.scl.Low()
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i2c.wait()
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i2c.wait()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinInput})
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i2c.scl.High()
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i2c.wait()
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i2c.nack = i2c.sda.Get()
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i2c.wait()
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// wait until transmission successful
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return nil
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}
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// sendAddress sends the address and start signal
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func (i2c *I2C) sendAddress(address uint16, write bool) error {
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data := (address << 1)
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if !write {
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data |= 1 // set read flag
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}
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i2c.scl.High()
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i2c.sda.Low()
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i2c.wait()
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i2c.wait()
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for i := 0; i < 8; i++ {
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i2c.scl.Low()
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if ((data >> (7 - i)) & 1) == 1 {
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i2c.sda.High()
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} else {
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i2c.sda.Low()
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}
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i2c.wait()
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i2c.wait()
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i2c.scl.High()
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i2c.wait()
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i2c.wait()
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}
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i2c.scl.Low()
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i2c.wait()
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i2c.wait()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinInput})
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i2c.scl.High()
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i2c.wait()
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i2c.nack = i2c.sda.Get()
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i2c.wait()
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// wait until bus ready
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return nil
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}
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func (i2c *I2C) signalStop() error {
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i2c.scl.Low()
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i2c.sda.Low()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinOutput})
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i2c.wait()
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i2c.wait()
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i2c.scl.High()
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i2c.wait()
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i2c.wait()
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i2c.sda.High()
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i2c.wait()
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i2c.wait()
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return nil
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}
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func (i2c *I2C) signalRead() error {
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i2c.wait()
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i2c.wait()
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i2c.scl.Low()
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i2c.sda.Low()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinOutput})
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i2c.wait()
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i2c.wait()
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i2c.scl.High()
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i2c.wait()
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i2c.wait()
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return nil
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}
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func (i2c *I2C) readByte() byte {
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var data byte
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for i := 0; i < 8; i++ {
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i2c.scl.Low()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinInput})
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i2c.wait()
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i2c.wait()
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i2c.scl.High()
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if i2c.sda.Get() {
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data |= 1 << (7 - i)
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}
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i2c.wait()
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i2c.wait()
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}
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return data
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}
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func (i2c *I2C) sendNack() error {
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i2c.wait()
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i2c.wait()
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i2c.scl.Low()
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i2c.sda.High()
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i2c.sda.Configure(machine.PinConfig{Mode: machine.PinOutput})
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i2c.wait()
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i2c.wait()
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i2c.scl.High()
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i2c.wait()
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i2c.wait()
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return nil
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}
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// WriteRegister transmits first the register and then the data to the
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// peripheral device.
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//
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// Many I2C-compatible devices are organized in terms of registers. This method
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// is a shortcut to easily write to such registers. Also, it only works for
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// devices with 7-bit addresses, which is the vast majority.
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func (i2c *I2C) WriteRegister(address uint8, register uint8, data []byte) error {
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buf := make([]uint8, len(data)+1)
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buf[0] = register
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copy(buf[1:], data)
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return i2c.Tx(uint16(address), buf, nil)
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}
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// ReadRegister transmits the register, restarts the connection as a read
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// operation, and reads the response.
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//
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// Many I2C-compatible devices are organized in terms of registers. This method
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// is a shortcut to easily read such registers. Also, it only works for devices
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// with 7-bit addresses, which is the vast majority.
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func (i2c *I2C) ReadRegister(address uint8, register uint8, data []byte) error {
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return i2c.Tx(uint16(address), []byte{register}, data)
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}
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@@ -0,0 +1,23 @@
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//go:build atsamd51 || atsame5x
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// +build atsamd51 atsame5x
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package i2csoft
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import (
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"device/arm"
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)
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func (i2c *I2C) wait() {
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// atsamd51
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// 1 : about 388kHz
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// 17 : about 97kHz
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wait := 1
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if i2c.baudrate < 400*1e3 {
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wait = 17
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}
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for i := 0; i < wait; i++ {
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arm.Asm(`nop`)
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}
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}
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@@ -0,0 +1,23 @@
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//go:build esp32
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// +build esp32
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package i2csoft
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import (
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"device"
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)
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func (i2c *I2C) wait() {
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// atsamd51
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// 10 : about 387kHz
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// 56 : about 99kHz
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wait := 10
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if i2c.baudrate < 400*1e3 {
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wait = 56
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}
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for i := 0; i < wait; i++ {
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device.Asm(`nop`)
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}
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}
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@@ -0,0 +1,22 @@
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//go:build !esp32 && !atsamd51 && !atsame5x
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// +build !esp32,!atsamd51,!atsame5x
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package i2csoft
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import (
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"device"
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)
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func (i2c *I2C) wait() {
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// atsamd21 @ 48MHz
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// 1 : about 360kHz
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// 24 : about 96kHz
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wait := 1
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if i2c.baudrate < 400*1e3 {
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wait = 19
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}
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for i := 0; i < wait; i++ {
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device.Asm(`nop`)
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}
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}
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Block a user