machine/esp32c3: implement i2c for esp32-c3
Этот коммит содержится в:
Dmitriy
Ron Evans
родитель
803ba4f54d
коммит
94459cefe5
2 изменённых файлов: 326 добавлений и 1 удалений
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@ -1,4 +1,4 @@
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//go:build atmega || nrf || sam || stm32 || fe310 || k210 || rp2040 || mimxrt1062
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//go:build atmega || nrf || sam || stm32 || fe310 || k210 || rp2040 || mimxrt1062 || esp32c3
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package machine
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@ -111,6 +111,10 @@ func (p Pin) outFunc() *volatile.Register32 {
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return (*volatile.Register32)(unsafe.Add(unsafe.Pointer(&esp.GPIO.FUNC0_OUT_SEL_CFG), uintptr(p)*4))
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}
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func (p Pin) pinReg() *volatile.Register32 {
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return (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(&esp.GPIO.PIN0)) + uintptr(p)*4)))
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}
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// inFunc returns the FUNCy_IN_SEL_CFG register used for configuring the input
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// function selection.
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func inFunc(signal uint32) *volatile.Register32 {
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@ -596,3 +600,324 @@ func (usbdev *USB_DEVICE) flush() {
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for usbdev.Bus.GetEP1_CONF_SERIAL_IN_EP_DATA_FREE() == 0 {
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}
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}
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// I2C code
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var (
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I2C0 = &I2C{}
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)
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type I2C struct{}
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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 // in Hz
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SCL Pin
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SDA Pin
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}
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const (
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clkXTAL = 0
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clkFOSC = 1
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clkXTALFrequency = uint32(40e6)
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clkFOSCFrequency = uint32(17.5e6)
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i2cClkSourceFrequency = clkXTALFrequency
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i2cClkSource = clkXTAL
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)
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func (i2c *I2C) Configure(config I2CConfig) error {
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i2c.initClock(config)
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i2c.initNoiseFilter()
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i2c.initPins(config)
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i2c.initFrequency(config)
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i2c.startMaster()
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return nil
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}
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// go: inline
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func (i2c *I2C) initClock(config I2CConfig) {
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// reset I2C clock
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esp.SYSTEM.SetPERIP_RST_EN0_EXT0_RST(1)
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esp.SYSTEM.SetPERIP_CLK_EN0_EXT0_CLK_EN(1)
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esp.SYSTEM.SetPERIP_RST_EN0_EXT0_RST(0)
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// disable interrupts
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esp.I2C.INT_ENA.ClearBits(0x3fff)
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esp.I2C.INT_CLR.ClearBits(0x3fff)
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esp.I2C.SetCLK_CONF_SCLK_SEL(i2cClkSource)
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esp.I2C.SetCLK_CONF_SCLK_ACTIVE(1)
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esp.I2C.SetCLK_CONF_SCLK_DIV_NUM(i2cClkSourceFrequency / (config.Frequency * 1024))
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esp.I2C.SetCTR_CLK_EN(1)
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}
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// go: inline
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func (i2c *I2C) initNoiseFilter() {
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esp.I2C.FILTER_CFG.Set(0x377)
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}
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// go: inline
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func (i2c *I2C) initPins(config I2CConfig) {
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var muxConfig uint32
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const function = 1 // function 1 is just GPIO
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// SDA
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muxConfig = function << esp.IO_MUX_GPIO_MCU_SEL_Pos
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// Make this pin an input pin (always).
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muxConfig |= esp.IO_MUX_GPIO_FUN_IE
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// Set drive strength: 0 is lowest, 3 is highest.
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muxConfig |= 1 << esp.IO_MUX_GPIO_FUN_DRV_Pos
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config.SDA.mux().Set(muxConfig)
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config.SDA.outFunc().Set(54)
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inFunc(54).Set(uint32(esp.GPIO_FUNC_IN_SEL_CFG_SIG_IN_SEL | config.SDA))
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config.SDA.Set(true)
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// Configure the pad with the given IO mux configuration.
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config.SDA.pinReg().SetBits(esp.GPIO_PIN_PIN_PAD_DRIVER)
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esp.GPIO.ENABLE.SetBits(1 << int(config.SDA))
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esp.I2C.SetCTR_SDA_FORCE_OUT(1)
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// SCL
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muxConfig = function << esp.IO_MUX_GPIO_MCU_SEL_Pos
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// Make this pin an input pin (always).
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muxConfig |= esp.IO_MUX_GPIO_FUN_IE
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// Set drive strength: 0 is lowest, 3 is highest.
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muxConfig |= 1 << esp.IO_MUX_GPIO_FUN_DRV_Pos
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config.SCL.mux().Set(muxConfig)
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config.SCL.outFunc().Set(53)
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inFunc(53).Set(uint32(config.SCL))
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config.SCL.Set(true)
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// Configure the pad with the given IO mux configuration.
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config.SCL.pinReg().SetBits(esp.GPIO_PIN_PIN_PAD_DRIVER)
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esp.GPIO.ENABLE.SetBits(1 << int(config.SCL))
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esp.I2C.SetCTR_SCL_FORCE_OUT(1)
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}
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// go: inline
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func (i2c *I2C) initFrequency(config I2CConfig) {
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clkmDiv := i2cClkSourceFrequency/(config.Frequency*1024) + 1
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sclkFreq := i2cClkSourceFrequency / clkmDiv
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halfCycle := sclkFreq / config.Frequency / 2
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//SCL
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sclLow := halfCycle
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sclWaitHigh := uint32(0)
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if config.Frequency > 50000 {
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sclWaitHigh = halfCycle / 8 // compensate the time when freq > 50K
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}
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sclHigh := halfCycle - sclWaitHigh
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// SDA
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sdaHold := halfCycle / 4
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sda_sample := halfCycle / 2
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setup := halfCycle
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hold := halfCycle
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esp.I2C.SetSCL_LOW_PERIOD(sclLow - 1)
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esp.I2C.SetSCL_HIGH_PERIOD(sclHigh)
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esp.I2C.SetSCL_HIGH_PERIOD_SCL_WAIT_HIGH_PERIOD(25)
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esp.I2C.SetSCL_RSTART_SETUP_TIME(setup)
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esp.I2C.SetSCL_STOP_SETUP_TIME(setup)
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esp.I2C.SetSCL_START_HOLD_TIME(hold - 1)
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esp.I2C.SetSCL_STOP_HOLD_TIME(hold - 1)
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esp.I2C.SetSDA_SAMPLE_TIME(sda_sample)
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esp.I2C.SetSDA_HOLD_TIME(sdaHold)
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}
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// go: inline
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func (i2c *I2C) startMaster() {
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// FIFO mode for data
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esp.I2C.SetFIFO_CONF_NONFIFO_EN(0)
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// Reset TX & RX buffers
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esp.I2C.SetFIFO_CONF_RX_FIFO_RST(1)
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esp.I2C.SetFIFO_CONF_RX_FIFO_RST(0)
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esp.I2C.SetFIFO_CONF_TX_FIFO_RST(1)
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esp.I2C.SetFIFO_CONF_TX_FIFO_RST(0)
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// set timeout value
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esp.I2C.TO.Set(0x10)
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// enable master mode
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esp.I2C.CTR.Set(0x113)
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esp.I2C.SetCTR_CONF_UPGATE(1)
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resetMaster()
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}
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// go: inline
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func resetMaster() {
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// reset FSM
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esp.I2C.SetCTR_FSM_RST(1)
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// clear the bus
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esp.I2C.SetSCL_SP_CONF_SCL_RST_SLV_NUM(9)
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esp.I2C.SetSCL_SP_CONF_SCL_RST_SLV_EN(1)
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esp.I2C.SetSCL_STRETCH_CONF_SLAVE_SCL_STRETCH_EN(1)
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esp.I2C.SetCTR_CONF_UPGATE(1)
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esp.I2C.FILTER_CFG.Set(0x377)
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// wait for SCL_RST_SLV_EN
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for esp.I2C.GetSCL_SP_CONF_SCL_RST_SLV_EN() != 0 {
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}
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esp.I2C.SetSCL_SP_CONF_SCL_RST_SLV_NUM(0)
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}
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type i2cCommandType = uint32
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type i2cAck = uint32
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const (
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i2cCMD_RSTART i2cCommandType = 6 << 11
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i2cCMD_WRITE i2cCommandType = 1<<11 | 1<<8 // WRITE + ack_check_en
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i2cCMD_READ i2cCommandType = 3<<11 | 1<<8 // READ + ack_check_en
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i2cCMD_READLAST i2cCommandType = 3<<11 | 5<<8 // READ + ack_check_en + NACK
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i2cCMD_STOP i2cCommandType = 2 << 11
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i2cCMD_END i2cCommandType = 4 << 11
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)
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type i2cCommand struct {
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cmd i2cCommandType
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data []byte
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head int
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}
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//go:linkname nanotime runtime.nanotime
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func nanotime() int64
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func (i2c *I2C) transmit(addr uint16, cmd []i2cCommand, timeoutMS int) error {
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const intMask = esp.I2C_INT_CLR_END_DETECT_INT_CLR_Msk | esp.I2C_INT_CLR_TRANS_COMPLETE_INT_CLR_Msk | esp.I2C_INT_STATUS_TIME_OUT_INT_ST_Msk | esp.I2C_INT_STATUS_NACK_INT_ST_Msk
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esp.I2C.INT_CLR.SetBits(intMask)
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esp.I2C.INT_ENA.SetBits(intMask)
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esp.I2C.SetCTR_CONF_UPGATE(1)
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defer func() {
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esp.I2C.INT_CLR.SetBits(intMask)
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esp.I2C.INT_ENA.ClearBits(intMask)
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}()
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timeoutNS := int64(timeoutMS) * 1000000
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needAddress := true
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needRestart := false
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var readTo []byte
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for cmdIdx, reg := 0, &esp.I2C.COMD0; cmdIdx < len(cmd); {
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c := &cmd[cmdIdx]
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switch c.cmd {
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case i2cCMD_RSTART:
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reg.Set(i2cCMD_RSTART)
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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cmdIdx++
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case i2cCMD_WRITE:
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count := 32
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if needAddress {
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needAddress = false
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esp.I2C.SetFIFO_DATA_FIFO_RDATA((uint32(addr) & 0x7f) << 1)
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count--
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esp.I2C.SLAVE_ADDR.Set(uint32(addr))
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esp.I2C.SetCTR_CONF_UPGATE(1)
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}
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for ; count > 0 && c.head < len(c.data); count, c.head = count-1, c.head+1 {
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esp.I2C.SetFIFO_DATA_FIFO_RDATA(uint32(c.data[c.head]))
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}
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reg.Set(i2cCMD_WRITE | uint32(32-count))
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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if c.head < len(c.data) {
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reg.Set(i2cCMD_END)
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reg = nil
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} else {
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cmdIdx++
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}
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needRestart = true
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case i2cCMD_READ:
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if needAddress {
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needAddress = false
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esp.I2C.SetFIFO_DATA_FIFO_RDATA((uint32(addr)&0x7f)<<1 | 1)
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esp.I2C.SLAVE_ADDR.Set(uint32(addr))
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reg.Set(i2cCMD_WRITE | 1)
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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}
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if needRestart {
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// We need to send RESTART again after i2cCMD_WRITE.
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reg.Set(i2cCMD_RSTART)
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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reg.Set(i2cCMD_WRITE | 1)
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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esp.I2C.SetFIFO_DATA_FIFO_RDATA((uint32(addr)&0x7f)<<1 | 1)
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needRestart = false
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}
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count := 32
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bytes := len(c.data) - c.head
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// Only last byte in sequence must be sent with ACK set to 1 to indicate end of data.
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split := bytes <= count
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if split {
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bytes--
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}
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if bytes > 32 {
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bytes = 32
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}
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reg.Set(i2cCMD_READ | uint32(bytes))
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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if split {
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reg.Set(i2cCMD_READLAST | 1)
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reg = (*volatile.Register32)(unsafe.Pointer((uintptr(unsafe.Pointer(reg)) + 4)))
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readTo = c.data[c.head : c.head+bytes+1] // read bytes + 1 last byte
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cmdIdx++
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} else {
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reg.Set(i2cCMD_END)
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readTo = c.data[c.head : c.head+bytes]
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reg = nil
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}
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case i2cCMD_STOP:
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reg.Set(i2cCMD_STOP)
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reg = nil
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cmdIdx++
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}
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if reg == nil {
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// transmit now
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esp.I2C.SetCTR_CONF_UPGATE(1)
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esp.I2C.SetCTR_TRANS_START(1)
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end := nanotime() + timeoutNS
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var mask uint32
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for mask = esp.I2C.INT_STATUS.Get(); mask&intMask == 0; mask = esp.I2C.INT_STATUS.Get() {
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if nanotime() > end {
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if readTo != nil {
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return errI2CReadTimeout
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}
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return errI2CWriteTimeout
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}
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}
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if mask == esp.I2C_INT_STATUS_TIME_OUT_INT_ST_Msk {
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if readTo != nil {
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return errI2CReadTimeout
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}
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return errI2CWriteTimeout
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}
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esp.I2C.INT_CLR.SetBits(intMask)
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for i := 0; i < len(readTo); i++ {
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readTo[i] = byte(esp.I2C.GetFIFO_DATA_FIFO_RDATA() & 0xff)
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c.head++
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}
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readTo = nil
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reg = &esp.I2C.COMD0
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}
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}
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return nil
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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) (err error) {
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// timeout in microseconds.
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const timeout = 100 * 1000 // 40ms is a reasonable time for a real-time system.
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cmd := make([]i2cCommand, 0, 8)
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cmd = append(cmd, i2cCommand{cmd: i2cCMD_RSTART})
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if len(w) > 0 {
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cmd = append(cmd, i2cCommand{cmd: i2cCMD_WRITE, data: w})
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}
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if len(r) > 0 {
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cmd = append(cmd, i2cCommand{cmd: i2cCMD_READ, data: r})
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}
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cmd = append(cmd, i2cCommand{cmd: i2cCMD_STOP})
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return i2c.transmit(addr, cmd, timeout)
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}
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