board/teensy40: Add I2C support (#1471)

* teensy40: add I2C support
Этот коммит содержится в:
ardnew 2022-06-22 04:28:50 -05:00 коммит произвёл GitHub
родитель 2825b4fe74
коммит afae6b3795
Не найден ключ, соответствующий данной подписи
Идентификатор ключа GPG: 4AEE18F83AFDEB23
4 изменённых файлов: 710 добавлений и 8 удалений

Просмотреть файл

@ -346,3 +346,49 @@ const (
I2C3_SDA_PIN = D25 I2C3_SDA_PIN = D25
I2C3_SCL_PIN = D24 I2C3_SCL_PIN = D24
) )
var (
I2C0 = I2C1 // I2C0 is an alias for I2C1 (LPI2C1)
I2C1 = &_I2C1
_I2C1 = I2C{
Bus: nxp.LPI2C1,
sda: I2C1_SDA_PIN, // D18 (PA17 [AD_B1_01])
scl: I2C1_SCL_PIN, // D19 (PA16 [AD_B1_00])
muxSDA: muxSelect{
mux: nxp.IOMUXC_LPI2C1_SDA_SELECT_INPUT_DAISY_GPIO_AD_B1_01_ALT3,
sel: &nxp.IOMUXC.LPI2C1_SDA_SELECT_INPUT,
},
muxSCL: muxSelect{
mux: nxp.IOMUXC_LPI2C1_SCL_SELECT_INPUT_DAISY_GPIO_AD_B1_00_ALT3,
sel: &nxp.IOMUXC.LPI2C1_SCL_SELECT_INPUT,
},
}
I2C2 = &_I2C2
_I2C2 = I2C{
Bus: nxp.LPI2C3,
sda: I2C2_SDA_PIN, // D17 (PA22 [AD_B1_06])
scl: I2C2_SCL_PIN, // D16 (PA23 [AD_B1_07])
muxSDA: muxSelect{
mux: nxp.IOMUXC_LPI2C3_SDA_SELECT_INPUT_DAISY_GPIO_AD_B1_06_ALT1,
sel: &nxp.IOMUXC.LPI2C3_SDA_SELECT_INPUT,
},
muxSCL: muxSelect{
mux: nxp.IOMUXC_LPI2C3_SCL_SELECT_INPUT_DAISY_GPIO_AD_B1_07_ALT1,
sel: &nxp.IOMUXC.LPI2C3_SCL_SELECT_INPUT,
},
}
I2C3 = &_I2C3
_I2C3 = I2C{
Bus: nxp.LPI2C4,
sda: I2C3_SDA_PIN, // D25 (PA13 [AD_B0_13])
scl: I2C3_SCL_PIN, // D24 (PA12 [AD_B0_12])
muxSDA: muxSelect{
mux: nxp.IOMUXC_LPI2C4_SDA_SELECT_INPUT_DAISY_GPIO_AD_B0_13_ALT0,
sel: &nxp.IOMUXC.LPI2C4_SDA_SELECT_INPUT,
},
muxSCL: muxSelect{
mux: nxp.IOMUXC_LPI2C4_SCL_SELECT_INPUT_DAISY_GPIO_AD_B0_12_ALT0,
sel: &nxp.IOMUXC.LPI2C4_SCL_SELECT_INPUT,
},
}
)

Просмотреть файл

@ -342,10 +342,10 @@ func (jt *pinJumpTable) dispatchInterrupt(interrupt.Interrupt) {
if status := gpio.ISR.Get() & gpio.IMR.Get(); status != 0 { if status := gpio.ISR.Get() & gpio.IMR.Get(); status != 0 {
gpio.ISR.Set(status) // clear interrupt gpio.ISR.Set(status) // clear interrupt
for status != 0 { for status != 0 {
p := Pin(bits.TrailingZeros32(status)) off := Pin(bits.TrailingZeros32(status)) // ctz
i := Pin(port + p) pin := Pin(port + off)
jt.lut[i](i) jt.lut[pin](pin)
status &^= 1 << p status &^= 1 << off
} }
} }
} }

657
src/machine/machine_mimxrt1062_i2c.go Обычный файл
Просмотреть файл

@ -0,0 +1,657 @@
//go:build mimxrt1062
// +build mimxrt1062
package machine
// I2C peripheral abstraction layer for the MIMXRT1062
import (
"device/nxp"
"errors"
)
const (
TWI_FREQ_BUS = 24000000 // LPI2C root clock is on 24 MHz OSC
TWI_FREQ_100KHZ = 100000 // StandardMode (100 kHz)
TWI_FREQ_400KHZ = 400000 // FastMode (400 kHz)
TWI_FREQ_1MHZ = 1000000 // FastModePlus (1 MHz)
TWI_FREQ_5MHZ = 5000000 // UltraFastMode (5 MHz)
TWI_FREQ_DEFAULT = TWI_FREQ_100KHZ // default to StandardMode (100 kHz)
)
var (
errI2CWriteTimeout = errors.New("I2C timeout during write")
errI2CReadTimeout = errors.New("I2C timeout during read")
errI2CBusReadyTimeout = errors.New("I2C timeout on bus ready")
errI2CSignalStartTimeout = errors.New("I2C timeout on signal start")
errI2CSignalReadTimeout = errors.New("I2C timeout on signal read")
errI2CSignalStopTimeout = errors.New("I2C timeout on signal stop")
errI2CAckExpected = errors.New("I2C error: expected ACK not NACK")
errI2CBusError = errors.New("I2C bus error")
errI2CNotConfigured = errors.New("I2C interface is not yet configured")
)
// I2CConfig is used to store config info for I2C.
type I2CConfig struct {
Frequency uint32
SDA Pin
SCL Pin
}
type I2C struct {
Bus *nxp.LPI2C_Type
// these pins are initialized by each global I2C variable declared in the
// board_teensy4x.go file according to the board manufacturer's default pin
// mapping. they can be overridden with the I2CConfig argument given to
// (*I2C) Configure(I2CConfig).
sda, scl Pin
// these hold the input selector ("daisy chain") values that select which pins
// are connected to the LPI2C device, and should be defined where the I2C
// instance is declared (e.g., in the board definition). see the godoc
// comments on type muxSelect for more details.
muxSDA, muxSCL muxSelect
}
type i2cDirection bool
const (
directionWrite i2cDirection = false
directionRead i2cDirection = true
)
func (dir i2cDirection) shift(addr uint16) uint32 {
if addr <<= 1; dir == directionRead {
addr |= 1
}
return uint32(addr) & 0xFF
}
// I2C enumerated types
type (
resultFlag uint32
statusFlag uint32
transferFlag uint32
commandFlag uint32
stateFlag uint32
)
const (
// general purpose results
resultSuccess resultFlag = 0x0 // success
resultFail resultFlag = 0x1 // fail
resultReadOnly resultFlag = 0x2 // read only failure
resultOutOfRange resultFlag = 0x3 // out of range access
resultInvalidArgument resultFlag = 0x4 // invalid argument check
// I2C-specific results
resultBusy resultFlag = 0x0384 + 0x0 // the controller is already performing a transfer
resultIdle resultFlag = 0x0384 + 0x1 // the peripheral driver is idle
resultNak resultFlag = 0x0384 + 0x2 // the peripheral device sent a NAK in response to a byte
resultFifoError resultFlag = 0x0384 + 0x3 // FIFO under run or overrun
resultBitError resultFlag = 0x0384 + 0x4 // transferred bit was not seen on the bus
resultArbitrationLost resultFlag = 0x0384 + 0x5 // arbitration lost error
resultPinLowTimeout resultFlag = 0x0384 + 0x6 // SCL or SDA were held low longer than the timeout
resultNoTransferInProgress resultFlag = 0x0384 + 0x7 // attempt to abort a transfer when one is not in progress
resultDmaRequestFail resultFlag = 0x0384 + 0x8 // DMA request failed
resultTimeout resultFlag = 0x0384 + 0x9 // timeout polling status flags
)
const (
statusTxReady statusFlag = nxp.LPI2C_MSR_TDF // transmit data flag
statusRxReady statusFlag = nxp.LPI2C_MSR_RDF // receive data flag
statusEndOfPacket statusFlag = nxp.LPI2C_MSR_EPF // end Packet flag
statusStopDetect statusFlag = nxp.LPI2C_MSR_SDF // stop detect flag
statusNackDetect statusFlag = nxp.LPI2C_MSR_NDF // NACK detect flag
statusArbitrationLost statusFlag = nxp.LPI2C_MSR_ALF // arbitration lost flag
statusFifoErr statusFlag = nxp.LPI2C_MSR_FEF // FIFO error flag
statusPinLowTimeout statusFlag = nxp.LPI2C_MSR_PLTF // pin low timeout flag
statusI2CDataMatch statusFlag = nxp.LPI2C_MSR_DMF // data match flag
statusBusy statusFlag = nxp.LPI2C_MSR_MBF // busy flag
statusBusBusy statusFlag = nxp.LPI2C_MSR_BBF // bus busy flag
// all flags which are cleared by the driver upon starting a transfer
statusClear statusFlag = statusEndOfPacket | statusStopDetect | statusNackDetect |
statusArbitrationLost | statusFifoErr | statusPinLowTimeout | statusI2CDataMatch
// IRQ sources enabled by the non-blocking transactional API
statusIrq statusFlag = statusArbitrationLost | statusTxReady | statusRxReady |
statusStopDetect | statusNackDetect | statusPinLowTimeout | statusFifoErr
// errors to check for
statusError statusFlag = statusNackDetect | statusArbitrationLost | statusFifoErr |
statusPinLowTimeout
)
// LPI2C transfer modes
const (
transferDefault transferFlag = 0x0 // transfer starts with a start signal, stops with a stop signal
transferNoStart transferFlag = 0x1 // don't send a start condition, address, and sub address
transferRepeatedStart transferFlag = 0x2 // send a repeated start condition
transferNoStop transferFlag = 0x4 // don't send a stop condition
)
// LPI2C FIFO commands
const (
commandTxData commandFlag = (0x0 << nxp.LPI2C_MTDR_CMD_Pos) & nxp.LPI2C_MTDR_CMD_Msk // transmit
commandRxData commandFlag = (0x1 << nxp.LPI2C_MTDR_CMD_Pos) & nxp.LPI2C_MTDR_CMD_Msk // receive
commandStop commandFlag = (0x2 << nxp.LPI2C_MTDR_CMD_Pos) & nxp.LPI2C_MTDR_CMD_Msk // generate STOP condition
commandStart commandFlag = (0x4 << nxp.LPI2C_MTDR_CMD_Pos) & nxp.LPI2C_MTDR_CMD_Msk // generate (REPEATED)START and transmit
)
// LPI2C transactional states
const (
stateIdle stateFlag = 0x0
stateSendCommand stateFlag = 0x1
stateIssueReadCommand stateFlag = 0x2
stateTransferData stateFlag = 0x3
stateStop stateFlag = 0x4
stateWaitForCompletion stateFlag = 0x5
)
func (i2c *I2C) setPins(c I2CConfig) (sda, scl Pin) {
// if both given pins are defined, or either receiver pin is undefined.
if 0 != c.SDA && 0 != c.SCL || 0 == i2c.sda || 0 == i2c.scl {
// override the receiver's pins.
i2c.sda, i2c.scl = c.SDA, c.SCL
}
// return the selected pins.
return i2c.sda, i2c.scl
}
// Configure is intended to setup an I2C interface for transmit/receive.
func (i2c *I2C) Configure(config I2CConfig) {
// init pins
sda, scl := i2c.setPins(config)
// configure the mux and pad control registers
sda.Configure(PinConfig{Mode: PinModeI2CSDA})
scl.Configure(PinConfig{Mode: PinModeI2CSCL})
// configure the mux input selector
i2c.muxSDA.connect()
i2c.muxSCL.connect()
freq := config.Frequency
if 0 == freq {
freq = TWI_FREQ_DEFAULT
}
// reset clock and registers, and enable LPI2C module interface
i2c.reset(freq)
}
func (i2c I2C) Tx(addr uint16, w, r []byte) error {
// perform transmit transfer
if nil != w {
// generate start condition on bus
if result := i2c.start(addr, directionWrite); resultSuccess != result {
return errI2CSignalStartTimeout
}
// ensure TX FIFO is empty
if result := i2c.waitForTxEmpty(); resultSuccess != result {
return errI2CBusReadyTimeout
}
// check if communication was successful
if status := statusFlag(i2c.Bus.MSR.Get()); 0 != (status & statusNackDetect) {
return errI2CAckExpected
}
// send transmit data
if result := i2c.controllerTransmit(w); resultSuccess != result {
return errI2CWriteTimeout
}
}
// perform receive transfer
if nil != r {
// generate (repeated-)start condition on bus
if result := i2c.start(addr, directionRead); resultSuccess != result {
return errI2CSignalStartTimeout
}
// read received data
if result := i2c.controllerReceive(r); resultSuccess != result {
return errI2CReadTimeout
}
}
// generate stop condition on bus
if result := i2c.stop(); resultSuccess != result {
return errI2CSignalStopTimeout
}
return nil
}
// WriteRegister transmits first the register and then the data to the
// peripheral device.
//
// Many I2C-compatible devices are organized in terms of registers. This method
// is a shortcut to easily write to such registers. Also, it only works for
// devices with 7-bit addresses, which is the vast majority.
func (i2c I2C) WriteRegister(address uint8, register uint8, data []byte) error {
option := transferOption{
flags: transferDefault, // transfer options bit mask (0 = normal transfer)
peripheral: uint16(address), // 7-bit peripheral address
direction: directionWrite, // directionRead or directionWrite
subaddress: uint16(register), // peripheral sub-address (transferred MSB first)
subaddressSize: 1, // byte length of sub-address (maximum = 4 bytes)
}
if result := i2c.controllerTransferPoll(option, data); resultSuccess != result {
return errI2CWriteTimeout
}
return nil
}
// ReadRegister transmits the register, restarts the connection as a read
// operation, and reads the response.
//
// Many I2C-compatible devices are organized in terms of registers. This method
// is a shortcut to easily read such registers. Also, it only works for devices
// with 7-bit addresses, which is the vast majority.
func (i2c I2C) ReadRegister(address uint8, register uint8, data []byte) error {
option := transferOption{
flags: transferDefault, // transfer options bit mask (0 = normal transfer)
peripheral: uint16(address), // 7-bit peripheral address
direction: directionRead, // directionRead or directionWrite
subaddress: uint16(register), // peripheral sub-address (transferred MSB first)
subaddressSize: 1, // byte length of sub-address (maximum = 4 bytes)
}
if result := i2c.controllerTransferPoll(option, data); resultSuccess != result {
return errI2CWriteTimeout
}
return nil
}
func (i2c *I2C) reset(freq uint32) {
// disable interface
i2c.Bus.MCR.ClearBits(nxp.LPI2C_MCR_MEN)
// software reset all interface registers
i2c.Bus.MCR.Set(nxp.LPI2C_MCR_RST)
// RST remains set until manually cleared!
i2c.Bus.MCR.ClearBits(nxp.LPI2C_MCR_RST)
// disable host request
i2c.Bus.MCFGR0.Set(0)
// enable ACK, use I2C 2-pin open drain mode
i2c.Bus.MCFGR1.Set(0)
// set FIFO watermarks (RX=1, TX=1)
mfcr := (uint32(0x1) << nxp.LPI2C_MFCR_RXWATER_Pos) & nxp.LPI2C_MFCR_RXWATER_Msk
mfcr |= (uint32(0x1) << nxp.LPI2C_MFCR_TXWATER_Pos) & nxp.LPI2C_MFCR_TXWATER_Msk
i2c.Bus.MFCR.Set(mfcr)
// configure clock using receiver frequency
i2c.setFrequency(freq)
// clear reset, and enable the interface
i2c.Bus.MCR.Set(nxp.LPI2C_MCR_MEN)
// wait for the I2C bus to idle
for i2c.Bus.MSR.Get()&nxp.LPI2C_MSR_BBF != 0 {
}
}
func (i2c *I2C) setFrequency(freq uint32) {
var (
bestPre uint32 = 0
bestClkHi uint32 = 0
bestError uint32 = 0xFFFFFFFF
)
// disable interface
wasEnabled := i2c.Bus.MCR.HasBits(nxp.LPI2C_MCR_MEN)
i2c.Bus.MCR.ClearBits(nxp.LPI2C_MCR_MEN)
// baud rate = (TWI_FREQ_BUS/(2^pre))/(CLKLO+1 + CLKHI+1 + FLOOR((2+FILTSCL)/(2^pre)))
// assume: CLKLO=2*CLKHI, SETHOLD=CLKHI, DATAVD=CLKHI/2
for pre := uint32(1); pre <= 128; pre *= 2 {
if bestError == 0 {
break
}
for clkHi := uint32(1); clkHi < 32; clkHi++ {
var absError, rate uint32
if clkHi == 1 {
rate = (TWI_FREQ_BUS / pre) / (1 + 3 + 2 + 2/pre)
} else {
rate = (TWI_FREQ_BUS / pre) / (3*clkHi + 2 + 2/pre)
}
if freq > rate {
absError = freq - rate
} else {
absError = rate - freq
}
if absError < bestError {
bestPre = pre
bestClkHi = clkHi
bestError = absError
// if the error is 0, then we can stop searching because we won't find a
// better match
if absError == 0 {
break
}
}
}
}
var (
clklo = func(n uint32) uint32 { return (n << nxp.LPI2C_MCCR0_CLKLO_Pos) & nxp.LPI2C_MCCR0_CLKLO_Msk }
clkhi = func(n uint32) uint32 { return (n << nxp.LPI2C_MCCR0_CLKHI_Pos) & nxp.LPI2C_MCCR0_CLKHI_Msk }
datavd = func(n uint32) uint32 { return (n << nxp.LPI2C_MCCR0_DATAVD_Pos) & nxp.LPI2C_MCCR0_DATAVD_Msk }
sethold = func(n uint32) uint32 { return (n << nxp.LPI2C_MCCR0_SETHOLD_Pos) & nxp.LPI2C_MCCR0_SETHOLD_Msk }
)
// StandardMode, FastMode, FastModePlus, and UltraFastMode
mccr0 := clkhi(bestClkHi)
if bestClkHi < 2 {
mccr0 |= (clklo(3) | sethold(2) | datavd(1))
} else {
mccr0 |= clklo(2*bestClkHi) | sethold(bestClkHi) | datavd(bestClkHi/2)
}
i2c.Bus.MCCR0.Set(mccr0)
i2c.Bus.MCCR1.Set(i2c.Bus.MCCR0.Get())
for i := uint32(0); i < 8; i++ {
if bestPre == (1 << i) {
bestPre = i
break
}
}
preMask := (bestPre << nxp.LPI2C_MCFGR1_PRESCALE_Pos) & nxp.LPI2C_MCFGR1_PRESCALE_Msk
i2c.Bus.MCFGR1.Set((i2c.Bus.MCFGR1.Get() & ^uint32(nxp.LPI2C_MCFGR1_PRESCALE_Msk)) | preMask)
var (
filtsda = func(n uint32) uint32 { return (n << nxp.LPI2C_MCFGR2_FILTSDA_Pos) & nxp.LPI2C_MCFGR2_FILTSDA_Msk }
filtscl = func(n uint32) uint32 { return (n << nxp.LPI2C_MCFGR2_FILTSCL_Pos) & nxp.LPI2C_MCFGR2_FILTSCL_Msk }
busidle = func(n uint32) uint32 { return (n << nxp.LPI2C_MCFGR2_BUSIDLE_Pos) & nxp.LPI2C_MCFGR2_BUSIDLE_Msk }
pinlow = func(n uint32) uint32 { return (n << nxp.LPI2C_MCFGR3_PINLOW_Pos) & nxp.LPI2C_MCFGR3_PINLOW_Msk }
mcfgr2, mcfgr3 uint32
)
const i2cClockStretchTimeout = 15000 // microseconds
if freq >= TWI_FREQ_5MHZ {
// I2C UltraFastMode 5 MHz
mcfgr2 = 0 // disable glitch filters and timeout for UltraFastMode
mcfgr3 = 0 //
} else if freq >= TWI_FREQ_1MHZ {
// I2C FastModePlus 1 MHz
mcfgr2 = filtsda(1) | filtscl(1) | busidle(2400) // 100us timeout
mcfgr3 = pinlow(i2cClockStretchTimeout*24/256 + 1)
} else if freq >= TWI_FREQ_400KHZ {
// I2C FastMode 400 kHz
mcfgr2 = filtsda(2) | filtscl(2) | busidle(3600) // 150us timeout
mcfgr3 = pinlow(i2cClockStretchTimeout*24/256 + 1)
} else {
// I2C StandardMode 100 kHz
mcfgr2 = filtsda(5) | filtscl(5) | busidle(3000) // 250us timeout
mcfgr3 = pinlow(i2cClockStretchTimeout*12/256 + 1)
}
i2c.Bus.MCFGR2.Set(mcfgr2)
i2c.Bus.MCFGR3.Set(mcfgr3)
// restore controller mode if it was enabled when called
if wasEnabled {
i2c.Bus.MCR.SetBits(nxp.LPI2C_MCR_MEN)
}
}
// checkStatus converts the status register to a resultFlag for return, and
// clears any errors if present.
func (i2c *I2C) checkStatus(status statusFlag) resultFlag {
result := resultSuccess
// check for error. these errors cause a stop to be sent automatically.
// we must clear the errors before a new transfer can start.
if status &= statusError; 0 != status {
// select the correct error code ordered by severity, bus issues first.
if 0 != (status & statusPinLowTimeout) {
result = resultPinLowTimeout
} else if 0 != (status & statusArbitrationLost) {
result = resultArbitrationLost
} else if 0 != (status & statusNackDetect) {
result = resultNak
} else if 0 != (status & statusFifoErr) {
result = resultFifoError
}
// clear the flags
i2c.Bus.MSR.Set(uint32(status))
// reset fifos. these flags clear automatically.
i2c.Bus.MCR.SetBits(nxp.LPI2C_MCR_RRF | nxp.LPI2C_MCR_RTF)
}
return result
}
func (i2c *I2C) getFIFOSize() (rx, tx uint32) { return 4, 4 }
func (i2c *I2C) getFIFOCount() (rx, tx uint32) {
mfsr := i2c.Bus.MFSR.Get()
return (mfsr & nxp.LPI2C_MFSR_RXCOUNT_Msk) >> nxp.LPI2C_MFSR_RXCOUNT_Pos,
(mfsr & nxp.LPI2C_MFSR_TXCOUNT_Msk) >> nxp.LPI2C_MFSR_TXCOUNT_Pos
}
func (i2c *I2C) waitForTxReady() resultFlag {
result := resultSuccess
_, txSize := i2c.getFIFOSize()
for {
_, txCount := i2c.getFIFOCount()
status := statusFlag(i2c.Bus.MSR.Get())
if result = i2c.checkStatus(status); resultSuccess != result {
break
}
if txSize-txCount > 0 {
break
}
}
return result
}
func (i2c *I2C) waitForTxEmpty() resultFlag {
result := resultSuccess
for {
_, txCount := i2c.getFIFOCount()
status := statusFlag(i2c.Bus.MSR.Get())
if result = i2c.checkStatus(status); resultSuccess != result {
break
}
if 0 == txCount {
break
}
}
return result
}
// isBusBusy checks if the I2C bus is busy, returning true if it is busy and we
// are not the ones driving it, otherwise false.
func (i2c *I2C) isBusBusy() bool {
status := statusFlag(i2c.Bus.MSR.Get())
return (0 != (status & statusBusBusy)) && (0 == (status & statusBusy))
}
// start sends a START signal and peripheral address on the I2C bus.
//
// This function is used to initiate a new controller mode transfer. First, the
// bus state is checked to ensure that another controller is not occupying the
// bus. Then a START signal is transmitted, followed by the 7-bit peripheral
// address. Note that this function does not actually wait until the START and
// address are successfully sent on the bus before returning.
func (i2c *I2C) start(address uint16, dir i2cDirection) resultFlag {
// return an error if the bus is already in use by another controller
if i2c.isBusBusy() {
return resultBusy
}
// clear all flags
i2c.Bus.MSR.Set(uint32(statusClear))
// turn off auto-stop
i2c.Bus.MCFGR1.ClearBits(nxp.LPI2C_MCFGR1_AUTOSTOP)
// wait until there is room in the FIFO
if result := i2c.waitForTxReady(); resultSuccess != result {
return result
}
// issue start command
i2c.Bus.MTDR.Set(uint32(commandStart) | dir.shift(address))
return resultSuccess
}
// stop sends a STOP signal on the I2C bus.
//
// This function does not return until the STOP signal is seen on the bus, or
// an error occurs.
func (i2c *I2C) stop() resultFlag {
const tryMax = 0 // keep waiting forever
// wait until there is room in the FIFO
result := i2c.waitForTxReady()
if resultSuccess != result {
return result
}
// send the STOP signal
i2c.Bus.MTDR.Set(uint32(commandStop))
// wait for the stop detected flag to set, indicating the transfer has
// completed on the bus. also check for errors while waiting.
try := 0
for resultSuccess == result && (0 == tryMax || try < tryMax) {
status := statusFlag(i2c.Bus.MSR.Get())
result = i2c.checkStatus(status)
if (0 != (status & statusStopDetect)) && (0 != (status & statusTxReady)) {
i2c.Bus.MSR.Set(uint32(statusStopDetect))
break
}
try++
}
if 0 != tryMax && try >= tryMax {
return resultTimeout
}
return result
}
// controllerReceive performs a polling receive transfer on the I2C bus.
func (i2c *I2C) controllerReceive(rxBuffer []byte) resultFlag {
const tryMax = 0 // keep trying forever
rxSize := len(rxBuffer)
if rxSize == 0 {
return resultSuccess
}
// wait until there is room in the FIFO
result := i2c.waitForTxReady()
if resultSuccess != result {
return result
}
sizeMask := (uint32(rxSize-1) << nxp.LPI2C_MTDR_DATA_Pos) & nxp.LPI2C_MTDR_DATA_Msk
i2c.Bus.MTDR.Set(uint32(commandRxData) | sizeMask)
// receive data
for rxSize > 0 {
// read LPI2C receive FIFO register. the register includes a flag to
// indicate whether the FIFO is empty, so we can both get the data and check
// if we need to keep reading using a single register read.
var data uint32
try := 0
for 0 == tryMax || try < tryMax {
// check for errors on the bus
status := statusFlag(i2c.Bus.MSR.Get())
result = i2c.checkStatus(status)
if resultSuccess != result {
return result
}
// read received data, break if FIFO was non-empty
data = i2c.Bus.MRDR.Get()
if 0 == (data & nxp.LPI2C_MRDR_RXEMPTY_Msk) {
break
}
try++
}
// ensure we didn't timeout waiting for data
if 0 != tryMax && try >= tryMax {
return resultTimeout
}
// copy data to RX buffer
rxBuffer[len(rxBuffer)-rxSize] = byte(data & nxp.LPI2C_MRDR_DATA_Msk)
rxSize--
}
return result
}
// controllerReceive performs a polling transmit transfer on the I2C bus.
func (i2c *I2C) controllerTransmit(txBuffer []byte) resultFlag {
txSize := len(txBuffer)
for txSize > 0 {
// wait until there is room in the FIFO
result := i2c.waitForTxReady()
if resultSuccess != result {
return result
}
// write byte into LPI2C data register
i2c.Bus.MTDR.Set(uint32(txBuffer[len(txBuffer)-txSize] & nxp.LPI2C_MTDR_DATA_Msk))
txSize--
}
return resultSuccess
}
type transferOption struct {
flags transferFlag // transfer options bit mask (0 = normal transfer)
peripheral uint16 // 7-bit peripheral address
direction i2cDirection // directionRead or directionWrite
subaddress uint16 // peripheral sub-address (transferred MSB first)
subaddressSize uint16 // byte length of sub-address (maximum = 4 bytes)
}
func (i2c *I2C) controllerTransferPoll(option transferOption, data []byte) resultFlag {
// return an error if the bus is already in use by another controller
if i2c.isBusBusy() {
return resultBusy
}
// clear all flags
i2c.Bus.MSR.Set(uint32(statusClear))
// turn off auto-stop
i2c.Bus.MCFGR1.ClearBits(nxp.LPI2C_MCFGR1_AUTOSTOP)
cmd := make([]uint16, 0, 7)
size := len(data)
direction := option.direction
if option.subaddressSize > 0 {
direction = directionWrite
}
// peripheral address
if 0 == (option.flags & transferNoStart) {
addr := direction.shift(option.peripheral)
cmd = append(cmd, uint16(uint32(commandStart)|addr))
}
// sub-address (MSB-first)
rem := option.subaddressSize
for rem > 0 {
rem--
cmd = append(cmd, (option.subaddress>>(8*rem))&0xFF)
}
// need to send repeated start if switching directions to read
if (0 != size) && (directionRead == option.direction) {
if directionWrite == direction {
addr := directionRead.shift(option.peripheral)
cmd = append(cmd, uint16(uint32(commandStart)|addr))
}
}
// send command buffer
result := resultSuccess
for _, c := range cmd {
// wait until there is room in the FIFO
if result = i2c.waitForTxReady(); resultSuccess != result {
return result
}
// write byte into LPI2C controller data register
i2c.Bus.MTDR.Set(uint32(c))
}
// send data
if option.direction == directionWrite && size > 0 {
result = i2c.controllerTransmit(data)
}
// receive data
if option.direction == directionRead && size > 0 {
result = i2c.controllerReceive(data)
}
if resultSuccess != result {
return result
}
if 0 == (option.flags & transferNoStop) {
result = i2c.stop()
}
return result
}

Просмотреть файл

@ -166,8 +166,9 @@ func initClocks() {
nxp.ClockIpLpi2c1.Enable(false) // disable LPI2C nxp.ClockIpLpi2c1.Enable(false) // disable LPI2C
nxp.ClockIpLpi2c2.Enable(false) // nxp.ClockIpLpi2c2.Enable(false) //
nxp.ClockIpLpi2c3.Enable(false) // nxp.ClockIpLpi2c3.Enable(false) //
nxp.ClockIpLpi2c4.Enable(false) //
nxp.DivIpLpi2c.Div(0) // divide LPI2C_CLK_PODF (DIV1) nxp.DivIpLpi2c.Div(0) // divide LPI2C_CLK_PODF (DIV1)
nxp.MuxIpLpi2c.Mux(0) // LPI2C select PLL3_SW_60M nxp.MuxIpLpi2c.Mux(1) // LPI2C select OSC
nxp.ClockIpCan1.Enable(false) // disable CAN nxp.ClockIpCan1.Enable(false) // disable CAN
nxp.ClockIpCan2.Enable(false) // nxp.ClockIpCan2.Enable(false) //
@ -266,7 +267,6 @@ func initClocks() {
} }
func enableTimerClocks() { func enableTimerClocks() {
nxp.ClockIpGpt1.Enable(true) // enable GPT/PIT nxp.ClockIpGpt1.Enable(true) // enable GPT/PIT
nxp.ClockIpGpt1S.Enable(true) // nxp.ClockIpGpt1S.Enable(true) //
nxp.ClockIpGpt2.Enable(true) // nxp.ClockIpGpt2.Enable(true) //
@ -275,7 +275,6 @@ func enableTimerClocks() {
} }
func enablePinClocks() { func enablePinClocks() {
nxp.ClockIpIomuxcGpr.Enable(true) // enable IOMUXC nxp.ClockIpIomuxcGpr.Enable(true) // enable IOMUXC
nxp.ClockIpIomuxc.Enable(true) // nxp.ClockIpIomuxc.Enable(true) //
@ -286,7 +285,6 @@ func enablePinClocks() {
} }
func enablePeripheralClocks() { func enablePeripheralClocks() {
nxp.ClockIpAdc1.Enable(true) // enable ADC nxp.ClockIpAdc1.Enable(true) // enable ADC
nxp.ClockIpAdc2.Enable(true) // nxp.ClockIpAdc2.Enable(true) //
@ -309,6 +307,7 @@ func enablePeripheralClocks() {
nxp.ClockIpLpi2c1.Enable(true) // enable LPI2C nxp.ClockIpLpi2c1.Enable(true) // enable LPI2C
nxp.ClockIpLpi2c2.Enable(true) // nxp.ClockIpLpi2c2.Enable(true) //
nxp.ClockIpLpi2c3.Enable(true) // nxp.ClockIpLpi2c3.Enable(true) //
nxp.ClockIpLpi2c4.Enable(true) //
nxp.ClockIpCan1.Enable(true) // enable CAN nxp.ClockIpCan1.Enable(true) // enable CAN
nxp.ClockIpCan2.Enable(true) // nxp.ClockIpCan2.Enable(true) //