657 строки
15 КиБ
Go
657 строки
15 КиБ
Go
// +build stm32,stm32f103xx
|
|
|
|
package machine
|
|
|
|
// Peripheral abstraction layer for the stm32.
|
|
|
|
import (
|
|
"device/stm32"
|
|
"runtime/interrupt"
|
|
"unsafe"
|
|
)
|
|
|
|
func CPUFrequency() uint32 {
|
|
return 72000000
|
|
}
|
|
|
|
const (
|
|
PinInput PinMode = 0 // Input mode
|
|
PinOutput10MHz PinMode = 1 // Output mode, max speed 10MHz
|
|
PinOutput2MHz PinMode = 2 // Output mode, max speed 2MHz
|
|
PinOutput50MHz PinMode = 3 // Output mode, max speed 50MHz
|
|
PinOutput PinMode = PinOutput2MHz
|
|
|
|
PinInputModeAnalog PinMode = 0 // Input analog mode
|
|
PinInputModeFloating PinMode = 4 // Input floating mode
|
|
PinInputModePullUpDown PinMode = 8 // Input pull up/down mode
|
|
PinInputModeReserved PinMode = 12 // Input mode (reserved)
|
|
|
|
PinOutputModeGPPushPull PinMode = 0 // Output mode general purpose push/pull
|
|
PinOutputModeGPOpenDrain PinMode = 4 // Output mode general purpose open drain
|
|
PinOutputModeAltPushPull PinMode = 8 // Output mode alt. purpose push/pull
|
|
PinOutputModeAltOpenDrain PinMode = 12 // Output mode alt. purpose open drain
|
|
)
|
|
|
|
// Configure this pin with the given I/O settings.
|
|
// stm32f1xx uses different technique for setting the GPIO pins than the stm32f407
|
|
func (p Pin) Configure(config PinConfig) {
|
|
// Configure the GPIO pin.
|
|
p.enableClock()
|
|
port := p.getPort()
|
|
pin := uint8(p) % 16
|
|
pos := (pin % 8) * 4
|
|
if pin < 8 {
|
|
port.CRL.ReplaceBits(uint32(config.Mode), 0xf, pos)
|
|
} else {
|
|
port.CRH.ReplaceBits(uint32(config.Mode), 0xf, pos)
|
|
}
|
|
}
|
|
|
|
func (p Pin) getPort() *stm32.GPIO_Type {
|
|
switch p / 16 {
|
|
case 0:
|
|
return stm32.GPIOA
|
|
case 1:
|
|
return stm32.GPIOB
|
|
case 2:
|
|
return stm32.GPIOC
|
|
case 3:
|
|
return stm32.GPIOD
|
|
case 4:
|
|
return stm32.GPIOE
|
|
case 5:
|
|
return stm32.GPIOF
|
|
case 6:
|
|
return stm32.GPIOG
|
|
default:
|
|
panic("machine: unknown port")
|
|
}
|
|
}
|
|
|
|
// enableClock enables the clock for this desired GPIO port.
|
|
func (p Pin) enableClock() {
|
|
switch p / 16 {
|
|
case 0:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPAEN)
|
|
case 1:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPBEN)
|
|
case 2:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPCEN)
|
|
case 3:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPDEN)
|
|
case 4:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPEEN)
|
|
case 5:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPFEN)
|
|
case 6:
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_IOPGEN)
|
|
default:
|
|
panic("machine: unknown port")
|
|
}
|
|
}
|
|
|
|
// Enable peripheral clock. Expand to include all the desired peripherals
|
|
func enableAltFuncClock(bus unsafe.Pointer) {
|
|
if bus == unsafe.Pointer(stm32.USART1) {
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_USART1EN)
|
|
} else if bus == unsafe.Pointer(stm32.USART2) {
|
|
stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_USART2EN)
|
|
} else if bus == unsafe.Pointer(stm32.I2C1) {
|
|
stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_I2C1EN)
|
|
} else if bus == unsafe.Pointer(stm32.SPI1) {
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_SPI1EN)
|
|
}
|
|
}
|
|
|
|
//---------- UART related types and code
|
|
|
|
// UART representation
|
|
type UART struct {
|
|
Buffer *RingBuffer
|
|
Bus *stm32.USART_Type
|
|
Interrupt interrupt.Interrupt
|
|
}
|
|
|
|
// Configure the TX and RX pins
|
|
func (uart UART) configurePins(config UARTConfig) {
|
|
|
|
// pins
|
|
switch config.TX {
|
|
case UART_ALT_TX_PIN:
|
|
// use alternate TX/RX pins via AFIO mapping
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_AFIOEN)
|
|
if uart.Bus == stm32.USART1 {
|
|
stm32.AFIO.MAPR.SetBits(stm32.AFIO_MAPR_USART1_REMAP)
|
|
} else if uart.Bus == stm32.USART2 {
|
|
stm32.AFIO.MAPR.SetBits(stm32.AFIO_MAPR_USART2_REMAP)
|
|
}
|
|
default:
|
|
// use standard TX/RX pins PA9 and PA10
|
|
}
|
|
config.TX.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
|
|
config.RX.Configure(PinConfig{Mode: PinInputModeFloating})
|
|
}
|
|
|
|
// Determine the divisor for USARTs to get the given baudrate
|
|
func (uart UART) getBaudRateDivisor(br uint32) uint32 {
|
|
|
|
// Note: PCLK2 (from APB2) used for USART1 and PCLK1 for USART2, 3, 4, 5
|
|
var divider uint32
|
|
if uart.Bus == stm32.USART1 {
|
|
// first divide by PCLK2 prescaler (div 1) and then desired baudrate
|
|
divider = CPUFrequency() / br
|
|
} else {
|
|
// first divide by PCLK1 prescaler (div 2) and then desired baudrate
|
|
divider = CPUFrequency() / 2 / br
|
|
}
|
|
return divider
|
|
}
|
|
|
|
//---------- SPI related types and code
|
|
|
|
type SPI struct {
|
|
Bus *stm32.SPI_Type
|
|
}
|
|
|
|
// There are 3 SPI interfaces on the STM32F103xx.
|
|
// Since the first interface is named SPI1, both SPI0 and SPI1 refer to SPI1.
|
|
// TODO: implement SPI2 and SPI3.
|
|
var (
|
|
SPI1 = SPI{Bus: stm32.SPI1}
|
|
SPI0 = SPI1
|
|
)
|
|
|
|
// Set baud rate for SPI
|
|
func (spi SPI) getBaudRate(config SPIConfig) uint32 {
|
|
var conf uint32
|
|
|
|
// set frequency dependent on PCLK2 prescaler (div 1)
|
|
switch config.Frequency {
|
|
case 125000:
|
|
// Note: impossible to achieve lower frequency with current PCLK2!
|
|
conf |= stm32.SPI_BaudRatePrescaler_256
|
|
case 250000:
|
|
conf |= stm32.SPI_BaudRatePrescaler_256
|
|
case 500000:
|
|
conf |= stm32.SPI_BaudRatePrescaler_128
|
|
case 1000000:
|
|
conf |= stm32.SPI_BaudRatePrescaler_64
|
|
case 2000000:
|
|
conf |= stm32.SPI_BaudRatePrescaler_32
|
|
case 4000000:
|
|
conf |= stm32.SPI_BaudRatePrescaler_16
|
|
case 8000000:
|
|
conf |= stm32.SPI_BaudRatePrescaler_8
|
|
default:
|
|
conf |= stm32.SPI_BaudRatePrescaler_256
|
|
}
|
|
return conf
|
|
}
|
|
|
|
// Configure SPI pins for input output and clock
|
|
func (spi SPI) configurePins(config SPIConfig) {
|
|
config.SCK.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
|
|
config.SDO.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltPushPull})
|
|
config.SDI.Configure(PinConfig{Mode: PinInputModeFloating})
|
|
}
|
|
|
|
//---------- I2C related types and code
|
|
|
|
type I2C struct {
|
|
Bus *stm32.I2C_Type
|
|
}
|
|
|
|
// There are 2 I2C interfaces on the STM32F103xx.
|
|
// Since the first interface is named I2C1, both I2C0 and I2C1 refer to I2C1.
|
|
// TODO: implement I2C2.
|
|
var (
|
|
I2C1 = I2C{Bus: stm32.I2C1}
|
|
I2C0 = I2C1
|
|
)
|
|
|
|
// I2CConfig is used to store config info for I2C.
|
|
type I2CConfig struct {
|
|
Frequency uint32
|
|
SCL Pin
|
|
SDA Pin
|
|
}
|
|
|
|
// Configure is intended to setup the I2C interface.
|
|
func (i2c I2C) Configure(config I2CConfig) {
|
|
// Default I2C bus speed is 100 kHz.
|
|
if config.Frequency == 0 {
|
|
config.Frequency = TWI_FREQ_100KHZ
|
|
}
|
|
|
|
// enable clock for I2C
|
|
stm32.RCC.APB1ENR.SetBits(stm32.RCC_APB1ENR_I2C1EN)
|
|
|
|
// I2C1 pins
|
|
switch config.SDA {
|
|
case PB9:
|
|
config.SCL = PB8
|
|
// use alternate I2C1 pins PB8/PB9 via AFIO mapping
|
|
stm32.RCC.APB2ENR.SetBits(stm32.RCC_APB2ENR_AFIOEN)
|
|
stm32.AFIO.MAPR.SetBits(stm32.AFIO_MAPR_I2C1_REMAP)
|
|
default:
|
|
// use default I2C1 pins PB6/PB7
|
|
config.SDA = SDA_PIN
|
|
config.SCL = SCL_PIN
|
|
}
|
|
|
|
config.SDA.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltOpenDrain})
|
|
config.SCL.Configure(PinConfig{Mode: PinOutput50MHz + PinOutputModeAltOpenDrain})
|
|
|
|
// Disable the selected I2C peripheral to configure
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_PE)
|
|
|
|
// pclk1 clock speed is main frequency divided by PCLK1 prescaler (div 2)
|
|
pclk1 := CPUFrequency() / 2
|
|
|
|
// set freqency range to PCLK1 clock speed in MHz
|
|
// aka setting the value 36 means to use 36 MHz clock
|
|
pclk1Mhz := pclk1 / 1000000
|
|
i2c.Bus.CR2.SetBits(pclk1Mhz)
|
|
|
|
switch config.Frequency {
|
|
case TWI_FREQ_100KHZ:
|
|
// Normal mode speed calculation
|
|
ccr := pclk1 / (config.Frequency * 2)
|
|
i2c.Bus.CCR.Set(ccr)
|
|
|
|
// duty cycle 2
|
|
i2c.Bus.CCR.ClearBits(stm32.I2C_CCR_DUTY)
|
|
|
|
// frequency standard mode
|
|
i2c.Bus.CCR.ClearBits(stm32.I2C_CCR_F_S)
|
|
|
|
// Set Maximum Rise Time for standard mode
|
|
i2c.Bus.TRISE.Set(pclk1Mhz)
|
|
|
|
case TWI_FREQ_400KHZ:
|
|
// Fast mode speed calculation
|
|
ccr := pclk1 / (config.Frequency * 3)
|
|
i2c.Bus.CCR.Set(ccr)
|
|
|
|
// duty cycle 2
|
|
i2c.Bus.CCR.ClearBits(stm32.I2C_CCR_DUTY)
|
|
|
|
// frequency fast mode
|
|
i2c.Bus.CCR.SetBits(stm32.I2C_CCR_F_S)
|
|
|
|
// Set Maximum Rise Time for fast mode
|
|
i2c.Bus.TRISE.Set(((pclk1Mhz * 300) / 1000))
|
|
}
|
|
|
|
// re-enable the selected I2C peripheral
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_PE)
|
|
}
|
|
|
|
// Tx does a single I2C transaction at the specified address.
|
|
// It clocks out the given address, writes the bytes in w, reads back len(r)
|
|
// bytes and stores them in r, and generates a stop condition on the bus.
|
|
func (i2c I2C) Tx(addr uint16, w, r []byte) error {
|
|
var err error
|
|
if len(w) != 0 {
|
|
// start transmission for writing
|
|
err = i2c.signalStart()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// send address
|
|
err = i2c.sendAddress(uint8(addr), true)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
for _, b := range w {
|
|
err = i2c.WriteByte(b)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
// sending stop here for write
|
|
err = i2c.signalStop()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
}
|
|
if len(r) != 0 {
|
|
// re-start transmission for reading
|
|
err = i2c.signalStart()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// 1 byte
|
|
switch len(r) {
|
|
case 1:
|
|
// send address
|
|
err = i2c.sendAddress(uint8(addr), false)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// Disable ACK of received data
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_ACK)
|
|
|
|
// clear timeout here
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.SR2.HasBits(stm32.I2C_SR2_MSL | stm32.I2C_SR2_BUSY) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
// Generate stop condition
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_STOP)
|
|
|
|
timeout = i2cTimeout
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_RxNE) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// Read and return data byte from I2C data register
|
|
r[0] = byte(i2c.Bus.DR.Get())
|
|
|
|
// wait for stop
|
|
return i2c.waitForStop()
|
|
|
|
case 2:
|
|
// enable pos
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_POS)
|
|
|
|
// Enable ACK of received data
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_ACK)
|
|
|
|
// send address
|
|
err = i2c.sendAddress(uint8(addr), false)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// clear address here
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.SR2.HasBits(stm32.I2C_SR2_MSL | stm32.I2C_SR2_BUSY) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
// Disable ACK of received data
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_ACK)
|
|
|
|
// wait for btf. we need a longer timeout here than normal.
|
|
timeout = 1000
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_BTF) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// Generate stop condition
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_STOP)
|
|
|
|
// read the 2 bytes by reading twice.
|
|
r[0] = byte(i2c.Bus.DR.Get())
|
|
r[1] = byte(i2c.Bus.DR.Get())
|
|
|
|
// wait for stop
|
|
err = i2c.waitForStop()
|
|
|
|
//disable pos
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_POS)
|
|
|
|
return err
|
|
|
|
case 3:
|
|
// Enable ACK of received data
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_ACK)
|
|
|
|
// send address
|
|
err = i2c.sendAddress(uint8(addr), false)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// clear address here
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.SR2.HasBits(stm32.I2C_SR2_MSL | stm32.I2C_SR2_BUSY) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
// Enable ACK of received data
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_ACK)
|
|
|
|
// wait for btf. we need a longer timeout here than normal.
|
|
timeout = 1000
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_BTF) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// Disable ACK of received data
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_ACK)
|
|
|
|
// read the first byte
|
|
r[0] = byte(i2c.Bus.DR.Get())
|
|
|
|
timeout = 1000
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_BTF) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// Generate stop condition
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_STOP)
|
|
|
|
// read the last 2 bytes by reading twice.
|
|
r[1] = byte(i2c.Bus.DR.Get())
|
|
r[2] = byte(i2c.Bus.DR.Get())
|
|
|
|
// wait for stop
|
|
return i2c.waitForStop()
|
|
|
|
default:
|
|
// more than 3 bytes of data to read
|
|
|
|
// send address
|
|
err = i2c.sendAddress(uint8(addr), false)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
// clear address here
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.SR2.HasBits(stm32.I2C_SR2_MSL | stm32.I2C_SR2_BUSY) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
for i := 0; i < len(r)-3; i++ {
|
|
// Enable ACK of received data
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_ACK)
|
|
|
|
// wait for btf. we need a longer timeout here than normal.
|
|
timeout = 1000
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_BTF) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// read the next byte
|
|
r[i] = byte(i2c.Bus.DR.Get())
|
|
}
|
|
|
|
// wait for btf. we need a longer timeout here than normal.
|
|
timeout = 1000
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_BTF) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// Disable ACK of received data
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_ACK)
|
|
|
|
// get third from last byte
|
|
r[len(r)-3] = byte(i2c.Bus.DR.Get())
|
|
|
|
// Generate stop condition
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_STOP)
|
|
|
|
// get second from last byte
|
|
r[len(r)-2] = byte(i2c.Bus.DR.Get())
|
|
|
|
timeout = i2cTimeout
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_RxNE) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CReadTimeout
|
|
}
|
|
}
|
|
|
|
// get last byte
|
|
r[len(r)-1] = byte(i2c.Bus.DR.Get())
|
|
|
|
// wait for stop
|
|
return i2c.waitForStop()
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
const i2cTimeout = 500
|
|
|
|
// signalStart sends a start signal.
|
|
func (i2c I2C) signalStart() error {
|
|
// Wait until I2C is not busy
|
|
timeout := i2cTimeout
|
|
for i2c.Bus.SR2.HasBits(stm32.I2C_SR2_BUSY) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CSignalStartTimeout
|
|
}
|
|
}
|
|
|
|
// clear stop
|
|
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_STOP)
|
|
|
|
// Generate start condition
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_START)
|
|
|
|
// Wait for I2C EV5 aka SB flag.
|
|
timeout = i2cTimeout
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_SB) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CSignalStartTimeout
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// signalStop sends a stop signal and waits for it to succeed.
|
|
func (i2c I2C) signalStop() error {
|
|
// Generate stop condition
|
|
i2c.Bus.CR1.SetBits(stm32.I2C_CR1_STOP)
|
|
|
|
// wait for stop
|
|
return i2c.waitForStop()
|
|
}
|
|
|
|
// waitForStop waits after a stop signal.
|
|
func (i2c I2C) waitForStop() error {
|
|
// Wait until I2C is stopped
|
|
timeout := i2cTimeout
|
|
for i2c.Bus.SR1.HasBits(stm32.I2C_SR1_STOPF) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CSignalStopTimeout
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Send address of device we want to talk to
|
|
func (i2c I2C) sendAddress(address uint8, write bool) error {
|
|
data := (address << 1)
|
|
if !write {
|
|
data |= 1 // set read flag
|
|
}
|
|
|
|
i2c.Bus.DR.Set(uint32(data))
|
|
|
|
// Wait for I2C EV6 event.
|
|
// Destination device acknowledges address
|
|
timeout := i2cTimeout
|
|
if write {
|
|
// EV6 which is ADDR flag.
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_ADDR) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
timeout = i2cTimeout
|
|
for !i2c.Bus.SR2.HasBits(stm32.I2C_SR2_MSL | stm32.I2C_SR2_BUSY | stm32.I2C_SR2_TRA) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
} else {
|
|
// I2C_EVENT_MASTER_RECEIVER_MODE_SELECTED which is ADDR flag.
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_ADDR) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// WriteByte writes a single byte to the I2C bus.
|
|
func (i2c I2C) WriteByte(data byte) error {
|
|
// Send data byte
|
|
i2c.Bus.DR.Set(uint32(data))
|
|
|
|
// Wait for I2C EV8_2 when data has been physically shifted out and
|
|
// output on the bus.
|
|
// I2C_EVENT_MASTER_BYTE_TRANSMITTED is TXE flag.
|
|
timeout := i2cTimeout
|
|
for !i2c.Bus.SR1.HasBits(stm32.I2C_SR1_TxE) {
|
|
timeout--
|
|
if timeout == 0 {
|
|
return errI2CWriteTimeout
|
|
}
|
|
}
|
|
|
|
return nil
|
|
}
|