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|
//go:build stm32l5 || stm32f7 || stm32l4 || stm32l0 || stm32wlx
package machine
import (
"device/stm32"
"unsafe"
)
//go:linkname ticks runtime.ticks
func ticks() int64
// I2C implementation for 'newer' STM32 MCUs, including the F7, L5 and L4
// series of MCUs.
//
// Currently, only 100KHz mode is supported
const (
flagBUSY = stm32.I2C_ISR_BUSY
flagTCR = stm32.I2C_ISR_TCR
flagRXNE = stm32.I2C_ISR_RXNE
flagSTOPF = stm32.I2C_ISR_STOPF
flagAF = stm32.I2C_ISR_NACKF
flagTXIS = stm32.I2C_ISR_TXIS
flagTXE = stm32.I2C_ISR_TXE
)
const (
MAX_NBYTE_SIZE = 255
// 100ms delay = 100e6ns / 16ns
// In runtime_stm32_timers.go, tick is fixed at 16ns per tick
TIMEOUT_TICKS = 100e6 / 16
I2C_NO_STARTSTOP = 0x0
I2C_GENERATE_START_WRITE = 0x80000000 | stm32.I2C_CR2_START
I2C_GENERATE_START_READ = 0x80000000 | stm32.I2C_CR2_START | stm32.I2C_CR2_RD_WRN
I2C_GENERATE_STOP = 0x80000000 | stm32.I2C_CR2_STOP
)
type I2C struct {
Bus *stm32.I2C_Type
AltFuncSelector uint8
}
// I2CConfig is used to store config info for I2C.
type I2CConfig struct {
SCL Pin
SDA Pin
}
func (i2c *I2C) Configure(config I2CConfig) error {
// disable I2C interface before any configuration changes
i2c.Bus.CR1.ClearBits(stm32.I2C_CR1_PE)
// enable clock for I2C
enableAltFuncClock(unsafe.Pointer(i2c.Bus))
// init pins
if config.SCL == 0 && config.SDA == 0 {
config.SCL = I2C0_SCL_PIN
config.SDA = I2C0_SDA_PIN
}
i2c.configurePins(config)
// Frequency range
i2c.Bus.TIMINGR.Set(i2c.getFreqRange())
// Disable Own Address1 before set the Own Address1 configuration
i2c.Bus.OAR1.ClearBits(stm32.I2C_OAR1_OA1EN)
// 7 bit addressing, no self address
i2c.Bus.OAR1.Set(stm32.I2C_OAR1_OA1EN)
// Enable the AUTOEND by default, and enable NACK (should be disable only during Slave process
i2c.Bus.CR2.Set(stm32.I2C_CR2_AUTOEND | stm32.I2C_CR2_NACK)
// Disable Own Address2 / Dual Addressing
i2c.Bus.OAR2.Set(0)
// Disable Generalcall and NoStretch, Enable peripheral
i2c.Bus.CR1.Set(stm32.I2C_CR1_PE)
return nil
}
func (i2c *I2C) Tx(addr uint16, w, r []byte) error {
if len(w) > 0 {
if err := i2c.controllerTransmit(addr, w); nil != err {
return err
}
}
if len(r) > 0 {
if err := i2c.controllerReceive(addr, r); nil != err {
return err
}
}
return nil
}
func (i2c *I2C) configurePins(config I2CConfig) {
config.SCL.ConfigureAltFunc(PinConfig{Mode: PinModeI2CSCL}, i2c.AltFuncSelector)
config.SDA.ConfigureAltFunc(PinConfig{Mode: PinModeI2CSDA}, i2c.AltFuncSelector)
}
func (i2c *I2C) controllerTransmit(addr uint16, w []byte) error {
start := ticks()
if !i2c.waitOnFlagUntilTimeout(flagBUSY, false, start) {
return errI2CBusReadyTimeout
}
pos := 0
xferCount := len(w)
xferSize := uint8(xferCount)
if xferCount > MAX_NBYTE_SIZE {
// Large write, indicate reload
xferSize = MAX_NBYTE_SIZE
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_RELOAD, I2C_GENERATE_START_WRITE)
} else {
// Small write, auto-end
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_AUTOEND, I2C_GENERATE_START_WRITE)
}
for xferCount > 0 {
if !i2c.waitOnTXISFlagUntilTimeout(start) {
return errI2CWriteTimeout
}
i2c.Bus.TXDR.Set(uint32(w[pos]))
pos++
xferCount--
xferSize--
// If we've written the last byte of this chunk
if xferCount != 0 && xferSize == 0 {
// Wait for Transfer Complete Reload to be flagged
if !i2c.waitOnFlagUntilTimeout(flagTCR, true, start) {
return errI2CWriteTimeout
}
if xferCount > MAX_NBYTE_SIZE {
// Large write remaining, indicate reload
xferSize = MAX_NBYTE_SIZE
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_RELOAD, I2C_NO_STARTSTOP)
} else {
// Small write, auto-end
xferSize = uint8(xferCount)
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_AUTOEND, I2C_NO_STARTSTOP)
}
}
}
if !i2c.waitOnStopFlagUntilTimeout(start) {
return errI2CWriteTimeout
}
i2c.clearFlag(stm32.I2C_ISR_STOPF)
i2c.resetCR2()
return nil
}
func (i2c *I2C) controllerReceive(addr uint16, r []byte) error {
start := ticks()
if !i2c.waitOnFlagUntilTimeout(flagBUSY, false, start) {
return errI2CBusReadyTimeout
}
pos := 0
xferCount := len(r)
xferSize := uint8(xferCount)
if xferCount > MAX_NBYTE_SIZE {
// Large read, indicate reload
xferSize = MAX_NBYTE_SIZE
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_RELOAD, I2C_GENERATE_START_READ)
} else {
// Small read, auto-end
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_AUTOEND, I2C_GENERATE_START_READ)
}
for xferCount > 0 {
if !i2c.waitOnRXNEFlagUntilTimeout(start) {
return errI2CWriteTimeout
}
r[pos] = uint8(i2c.Bus.RXDR.Get())
pos++
xferCount--
xferSize--
// If we've read the last byte of this chunk
if xferCount != 0 && xferSize == 0 {
// Wait for Transfer Complete Reload to be flagged
if !i2c.waitOnFlagUntilTimeout(flagTCR, true, start) {
return errI2CWriteTimeout
}
if xferCount > MAX_NBYTE_SIZE {
// Large read remaining, indicate reload
xferSize = MAX_NBYTE_SIZE
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_RELOAD, I2C_NO_STARTSTOP)
} else {
// Small read, auto-end
xferSize = uint8(xferCount)
i2c.transferConfig(addr, xferSize, stm32.I2C_CR2_AUTOEND, I2C_NO_STARTSTOP)
}
}
}
if !i2c.waitOnStopFlagUntilTimeout(start) {
return errI2CWriteTimeout
}
i2c.clearFlag(stm32.I2C_ISR_STOPF)
i2c.resetCR2()
return nil
}
func (i2c *I2C) waitOnFlagUntilTimeout(flag uint32, set bool, startTicks int64) bool {
for i2c.hasFlag(flag) != set {
if (ticks() - startTicks) > TIMEOUT_TICKS {
return false
}
}
return true
}
func (i2c *I2C) waitOnRXNEFlagUntilTimeout(startTicks int64) bool {
for !i2c.hasFlag(flagRXNE) {
if i2c.isAcknowledgeFailed(startTicks) {
return false
}
if i2c.hasFlag(flagSTOPF) {
i2c.clearFlag(flagSTOPF)
i2c.resetCR2()
return false
}
if (ticks() - startTicks) > TIMEOUT_TICKS {
return false
}
}
return true
}
func (i2c *I2C) waitOnTXISFlagUntilTimeout(startTicks int64) bool {
for !i2c.hasFlag(flagTXIS) {
if i2c.isAcknowledgeFailed(startTicks) {
return false
}
if (ticks() - startTicks) > TIMEOUT_TICKS {
return false
}
}
return true
}
func (i2c *I2C) waitOnStopFlagUntilTimeout(startTicks int64) bool {
for !i2c.hasFlag(flagSTOPF) {
if i2c.isAcknowledgeFailed(startTicks) {
return false
}
if (ticks() - startTicks) > TIMEOUT_TICKS {
return false
}
}
return true
}
func (i2c *I2C) isAcknowledgeFailed(startTicks int64) bool {
if i2c.hasFlag(flagAF) {
// Wait until STOP Flag is reset
// AutoEnd should be initiate after AF
for !i2c.hasFlag(flagSTOPF) {
if (ticks() - startTicks) > TIMEOUT_TICKS {
return true
}
}
i2c.clearFlag(flagAF)
i2c.clearFlag(flagSTOPF)
i2c.flushTXDR()
i2c.resetCR2()
return true
}
return false
}
func (i2c *I2C) flushTXDR() {
// If a pending TXIS flag is set, write a dummy data in TXDR to clear it
if i2c.hasFlag(flagTXIS) {
i2c.Bus.TXDR.Set(0)
}
// Flush TX register if not empty
if !i2c.hasFlag(flagTXE) {
i2c.clearFlag(flagTXE)
}
}
func (i2c *I2C) resetCR2() {
i2c.Bus.CR2.ClearBits(stm32.I2C_CR2_SADD_Msk |
stm32.I2C_CR2_HEAD10R_Msk |
stm32.I2C_CR2_NBYTES_Msk |
stm32.I2C_CR2_RELOAD_Msk |
stm32.I2C_CR2_RD_WRN_Msk)
}
func (i2c *I2C) transferConfig(addr uint16, size uint8, mode uint32, request uint32) {
mask := uint32(stm32.I2C_CR2_SADD_Msk |
stm32.I2C_CR2_NBYTES_Msk |
stm32.I2C_CR2_RELOAD_Msk |
stm32.I2C_CR2_AUTOEND_Msk |
(stm32.I2C_CR2_RD_WRN & uint32(request>>(31-stm32.I2C_CR2_RD_WRN_Pos))) |
stm32.I2C_CR2_START_Msk |
stm32.I2C_CR2_STOP_Msk)
value := (uint32(addr<<1) & stm32.I2C_CR2_SADD_Msk) |
((uint32(size) << stm32.I2C_CR2_NBYTES_Pos) & stm32.I2C_CR2_NBYTES_Msk) |
mode | request
i2c.Bus.CR2.ReplaceBits(value, mask, 0)
}
func (i2c *I2C) hasFlag(flag uint32) bool {
return i2c.Bus.ISR.HasBits(flag)
}
func (i2c *I2C) clearFlag(flag uint32) {
if flag == stm32.I2C_ISR_TXE {
i2c.Bus.ISR.SetBits(flag)
} else {
i2c.Bus.ICR.SetBits(flag)
}
}
|
