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Merge pull request #352 from DCC-EX/STM32_I2C_PMA_NEIL

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Stm32 i2 c pma neil
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pmantoine 2023-09-13 16:43:59 +08:00 committed by GitHub
commit a8321fff42
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5 changed files with 336 additions and 141 deletions
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2
I2CManager.cpp
View File

@ -92,7 +92,7 @@ void I2CManagerClass::begin(void) {
// Probe and list devices. Use standard mode
// (clock speed 100kHz) for best device compatibility.
_setClock(100000);
unsigned long originalTimeout = _timeout;
uint32_t originalTimeout = _timeout;
setTimeout(1000); // use 1ms timeout for probes
#if defined(I2C_EXTENDED_ADDRESS)

5
I2CManager.h
View File

@ -485,7 +485,7 @@ private:
// When retries are enabled, the timeout applies to each
// try, and failure from timeout does not get retried.
// A value of 0 means disable timeout monitoring.
unsigned long _timeout = 100000UL;
uint32_t _timeout = 100000UL;
// Finish off request block by waiting for completion and posting status.
uint8_t finishRB(I2CRB *rb, uint8_t status);
@ -532,13 +532,14 @@ private:
uint8_t bytesToSend = 0;
uint8_t bytesToReceive = 0;
uint8_t operation = 0;
unsigned long startTime = 0;
uint32_t startTime = 0;
uint8_t muxPhase = 0;
uint8_t muxAddress = 0;
uint8_t muxData[1];
uint8_t deviceAddress;
const uint8_t *sendBuffer;
uint8_t *receiveBuffer;
uint8_t transactionState = 0;
volatile uint32_t pendingClockSpeed = 0;

13
I2CManager_NonBlocking.h
View File

@ -172,6 +172,10 @@ void I2CManagerClass::startTransaction() {
* Function to queue a request block and initiate operations.
***************************************************************************/
void I2CManagerClass::queueRequest(I2CRB *req) {
if (((req->operation & OPERATION_MASK) == OPERATION_READ) && req->readLen == 0)
return; // Ignore null read
req->status = I2C_STATUS_PENDING;
req->nextRequest = NULL;
ATOMIC_BLOCK() {
@ -184,6 +188,7 @@ void I2CManagerClass::queueRequest(I2CRB *req) {
}
/***************************************************************************
* Initiate a write to an I2C device (non-blocking operation)
***************************************************************************/
@ -240,8 +245,8 @@ void I2CManagerClass::checkForTimeout() {
I2CRB *t = queueHead;
if (state==I2C_STATE_ACTIVE && t!=0 && t==currentRequest && _timeout > 0) {
// Check for timeout
unsigned long elapsed = micros() - startTime;
if (elapsed > _timeout) {
int32_t elapsed = micros() - startTime;
if (elapsed > (int32_t)_timeout) {
#ifdef DIAG_IO
//DIAG(F("I2CManager Timeout on %s"), t->i2cAddress.toString());
#endif
@ -300,12 +305,12 @@ void I2CManagerClass::handleInterrupt() {
// Check if current request has completed. If there's a current request
// and state isn't active then state contains the completion status of the request.
if (state == I2C_STATE_COMPLETED && currentRequest != NULL) {
if (state == I2C_STATE_COMPLETED && currentRequest != NULL && currentRequest == queueHead) {
// Operation has completed.
if (completionStatus == I2C_STATUS_OK || ++retryCounter > MAX_I2C_RETRIES
|| currentRequest->operation & OPERATION_NORETRY)
{
// Status is OK, or has failed and retry count exceeded, or retries disabled.
// Status is OK, or has failed and retry count exceeded, or failed and retries disabled.
#if defined(I2C_EXTENDED_ADDRESS)
if (muxPhase == MuxPhase_PROLOG ) {
overallStatus = completionStatus;

431
I2CManager_STM32.h
View File

@ -26,27 +26,42 @@
#include "I2CManager.h"
#include "I2CManager_NonBlocking.h" // to satisfy intellisense
//#include <avr/io.h>
//#include <avr/interrupt.h>
#include <wiring_private.h>
#include "stm32f4xx_hal_rcc.h"
/***************************************************************************
* Interrupt handler.
* IRQ handler for SERCOM3 which is the default I2C definition for Arduino Zero
* compatible variants such as the Sparkfun SAMD21 Dev Breakout etc.
* Later we may wish to allow use of an alternate I2C bus, or more than one I2C
* bus on the SAMD architecture
***************************************************************************/
/*****************************************************************************
* STM32F4xx I2C native driver support
*
* Nucleo-64 and Nucleo-144 boards all use I2C1 as the default I2C peripheral
* Later we may wish to support other STM32 boards, allow use of an alternate
* I2C bus, or more than one I2C bus on the STM32 architecture
*****************************************************************************/
#if defined(I2C_USE_INTERRUPTS) && defined(ARDUINO_ARCH_STM32)
void I2C1_IRQHandler() {
#if defined(ARDUINO_NUCLEO_F411RE) || defined(ARDUINO_NUCLEO_F446RE) || defined(ARDUINO_NUCLEO_F412ZG) || defined(ARDUINO_NUCLEO_F429ZI) || defined(ARDUINO_NUCLEO_F446ZE)
// Assume I2C1 for now - default I2C bus on Nucleo-F411RE and likely all Nucleo-64
// and Nucleo-144variants
I2C_TypeDef *s = I2C1;
// In init we will ask the STM32 HAL layer for the configured APB1 clock frequency in Hz
uint32_t APB1clk1; // Peripheral Input Clock speed in Hz.
uint32_t i2c_MHz; // Peripheral Input Clock speed in MHz.
// IRQ handler for I2C1, replacing the weak definition in the STM32 HAL
extern "C" void I2C1_EV_IRQHandler(void) {
I2CManager.handleInterrupt();
}
extern "C" void I2C1_ER_IRQHandler(void) {
I2CManager.handleInterrupt();
}
#else
#warning STM32 board selected is not yet supported - so I2C1 peripheral is not defined
#endif
#endif
// Assume I2C1 for now - default I2C bus on Nucleo-F411RE and likely Nucleo-64 variants
I2C_TypeDef *s = I2C1;
#define I2C_IRQn I2C1_EV_IRQn
#define I2C_BUSFREQ 16
// Peripheral Input Clock speed in MHz.
// For STM32F446RE, the speed is 45MHz. Ideally, this should be determined
// at run-time from the APB1 clock, as it can vary from STM32 family to family.
// #define I2C_PERIPH_CLK 45
// I2C SR1 Status Register #1 bit definitions for convenience
// #define I2C_SR1_SMBALERT (1<<15) // SMBus alert
@ -80,52 +95,55 @@ I2C_TypeDef *s = I2C1;
// #define I2C_CR1_SMBUS (1<<1) // SMBus mode, 1=SMBus, 0=I2C
// #define I2C_CR1_PE (1<<0) // I2C Peripheral enable
// States of the STM32 I2C driver state machine
enum {TS_IDLE,TS_START,TS_W_ADDR,TS_W_DATA,TS_W_STOP,TS_R_ADDR,TS_R_DATA,TS_R_STOP};
/***************************************************************************
* Set I2C clock speed register. This should only be called outside of
* a transmission. The I2CManagerClass::_setClock() function ensures
* that it is only called at the beginning of an I2C transaction.
***************************************************************************/
void I2CManagerClass::I2C_setClock(uint32_t i2cClockSpeed) {
// Calculate a rise time appropriate to the requested bus speed
// Use 10x the rise time spec to enable integer divide of 62.5ns clock period
// Use 10x the rise time spec to enable integer divide of 50ns clock period
uint16_t t_rise;
uint32_t ccr_freq;
if (i2cClockSpeed < 200000L) {
// i2cClockSpeed = 100000L;
t_rise = 0x11; // (1000ns /62.5ns) + 1;
}
else if (i2cClockSpeed < 800000L)
while (s->CR1 & I2C_CR1_STOP); // Prevents lockup by guarding further
// writes to CR1 while STOP is being executed!
// Disable the I2C device, as TRISE can only be programmed whilst disabled
s->CR1 &= ~(I2C_CR1_PE); // Disable I2C
if (i2cClockSpeed > 100000L)
{
if (i2cClockSpeed > 400000L)
i2cClockSpeed = 400000L;
t_rise = 0x06; // (300ns / 62.5ns) + 1;
// } else if (i2cClockSpeed < 1200000L) {
// i2cClockSpeed = 1000000L;
// t_rise = 120;
t_rise = 300; // nanoseconds
}
else
{
i2cClockSpeed = 100000L;
t_rise = 0x11; // (1000ns /62.5ns) + 1;
t_rise = 1000; // nanoseconds
}
// Enable the I2C master mode
s->CR1 &= ~(I2C_CR1_PE); // Enable I2C
// Software reset the I2C peripheral
// s->CR1 |= I2C_CR1_SWRST; // reset the I2C
// Release reset
// s->CR1 &= ~(I2C_CR1_SWRST); // Normal operation
// Calculate baudrate - using a rise time appropriate for the speed
ccr_freq = I2C_BUSFREQ * 1000000 / i2cClockSpeed / 2;
// Configure the rise time register
s->TRISE = (t_rise / (1000 / i2c_MHz)) + 1;
// Bit 15: I2C Master mode, 0=standard, 1=Fast Mode
// Bit 14: Duty, fast mode duty cycle
// Bit 11-0: FREQR = 16MHz => TPCLK1 = 62.5ns, so CCR divisor must be 0x50 (80 * 62.5ns = 5000ns)
s->CCR = (uint16_t)ccr_freq;
// Configure the rise time register
s->TRISE = t_rise; // 1000 ns / 62.5 ns = 16 + 1
// Bit 14: Duty, fast mode duty cycle (use 2:1)
// Bit 11-0: FREQR
if (i2cClockSpeed > 100000L) {
// In fast mode, I2C period is 3 * CCR * TPCLK1.
//APB1clk1 / 3 / i2cClockSpeed = 38, but that results in 306KHz not 400!
ccr_freq = 30; // So 30 gives 396KHz or so!
s->CCR = (uint16_t)(ccr_freq | 0x8000); // We need Fast Mode set
} else {
// In standard mode, I2C period is 2 * CCR * TPCLK1
ccr_freq = (APB1clk1 / 2 / i2cClockSpeed); // Should be 225 for 45Mhz APB1 clock
s->CCR |= (uint16_t)ccr_freq;
}
// Enable the I2C master mode
s->CR1 |= I2C_CR1_PE; // Enable I2C
@ -136,32 +154,51 @@ void I2CManagerClass::I2C_setClock(uint32_t i2cClockSpeed) {
***************************************************************************/
void I2CManagerClass::I2C_init()
{
//Setting up the clocks
RCC->APB1ENR |= (1<<21); // Enable I2C CLOCK
RCC->AHB1ENR |= (1<<1); // Enable GPIOB CLOCK for PB8/PB9
// Query the clockspeed from the STM32 HAL layer
APB1clk1 = HAL_RCC_GetPCLK1Freq();
i2c_MHz = APB1clk1 / 1000000UL;
// Enable clocks
RCC->APB1ENR |= RCC_APB1ENR_I2C1EN;//(1 << 21); // Enable I2C CLOCK
// Reset the I2C1 peripheral to initial state
RCC->APB1RSTR |= RCC_APB1RSTR_I2C1RST;
RCC->APB1RSTR &= ~RCC_APB1RSTR_I2C1RST;
// Standard I2C pins are SCL on PB8 and SDA on PB9
RCC->AHB1ENR |= (1<<1); // Enable GPIOB CLOCK for PB8/PB9
// Bits (17:16)= 1:0 --> Alternate Function for Pin PB8;
// Bits (19:18)= 1:0 --> Alternate Function for Pin PB9
GPIOB->MODER &= ~((3<<(8*2)) | (3<<(9*2))); // Clear all MODER bits for PB8 and PB9
GPIOB->MODER |= (2<<(8*2)) | (2<<(9*2)); // PB8 and PB9 set to ALT function
GPIOB->OTYPER |= (1<<8) | (1<<9); // PB8 and PB9 set to open drain output capability
GPIOB->OSPEEDR |= (3<<(8*2)) | (3<<(9*2)); // PB8 and PB9 set to High Speed mode
GPIOB->PUPDR &= ~((3<<(8*2)) | (3<<(9*2))); // Clear all PUPDR bits for PB8 and PB9
GPIOB->PUPDR |= (1<<(8*2)) | (1<<(9*2)); // PB8 and PB9 set to pull-up capability
// Alt Function High register routing pins PB8 and PB9 for I2C1:
// Bits (3:2:1:0) = 0:1:0:0 --> AF4 for pin PB8
// Bits (7:6:5:4) = 0:1:0:0 --> AF4 for pin PB9
GPIOB->AFR[1] &= ~((15<<0) | (15<<4)); // Clear all AFR bits for PB8 on low nibble, PB9 on next nibble up
GPIOB->AFR[1] |= (4<<0) | (4<<4); // PB8 on low nibble, PB9 on next nibble up
// Software reset the I2C peripheral
s->CR1 |= I2C_CR1_SWRST; // reset the I2C
asm("nop"); // wait a bit... suggestion from online!
s->CR1 &= ~(I2C_CR1_SWRST); // Normal operation
// Program the peripheral input clock in CR2 Register in order to generate correct timings
s->CR2 |= I2C_BUSFREQ; // PCLK1 FREQUENCY in MHz
// Clear all bits in I2C CR2 register except reserved bits
s->CR2 &= 0xE000;
// Set I2C peripheral clock frequency
// s->CR2 |= I2C_PERIPH_CLK;
s->CR2 |= i2c_MHz;
// set own address to 00 - not used in master mode
I2C1->OAR1 = (1 << 14); // bit 14 should be kept at 1 according to the datasheet
#if defined(I2C_USE_INTERRUPTS)
// Setting NVIC
NVIC_SetPriority(I2C_IRQn, 1); // Match default priorities
NVIC_EnableIRQ(I2C_IRQn);
NVIC_SetPriority(I2C1_EV_IRQn, 1); // Match default priorities
NVIC_EnableIRQ(I2C1_EV_IRQn);
NVIC_SetPriority(I2C1_ER_IRQn, 1); // Match default priorities
NVIC_EnableIRQ(I2C1_ER_IRQn);
// CR2 Interrupt Settings
// Bit 15-13: reserved
@ -172,23 +209,25 @@ void I2CManagerClass::I2C_init()
// Bit 8: ITERREN - Error interrupt enable
// Bit 7-6: reserved
// Bit 5-0: FREQ - Peripheral clock frequency (max 50MHz)
// s->CR2 |= 0x0700; // Enable Buffer, Event and Error interrupts
s->CR2 |= 0x0300; // Enable Event and Error interrupts
s->CR2 |= (I2C_CR2_ITBUFEN | I2C_CR2_ITEVTEN | I2C_CR2_ITERREN); // Enable Buffer, Event and Error interrupts
#endif
// Calculate baudrate and set default rate for now
// Configure the Clock Control Register for 100KHz SCL frequency
// Bit 15: I2C Master mode, 0=standard, 1=Fast Mode
// Bit 14: Duty, fast mode duty cycle
// Bit 11-0: FREQR = 16MHz => TPCLK1 = 62.5ns, so CCR divisor must be 0x50 (80 * 62.5ns = 5000ns)
s->CCR = 0x0050;
// Bit 11-0: so CCR divisor would be clk / 2 / 100000 (where clk is in Hz)
// s->CCR = I2C_PERIPH_CLK * 5;
s->CCR &= ~(0x3000); // Clear all bits except 12 and 13 which must remain per reset value
s->CCR |= (APB1clk1 / 2 / 100000UL); // i2c_MHz * 5;
// s->CCR = i2c_MHz * 5;
// Configure the rise time register - max allowed in 1000ns
s->TRISE = 0x0011; // 1000 ns / 62.5 ns = 16 + 1
// Configure the rise time register - max allowed is 1000ns, so value = 1000ns * I2C_PERIPH_CLK MHz / 1000 + 1.
// s->TRISE = I2C_PERIPH_CLK + 1; // 1000 ns / 50 ns = 20 + 1 = 21
s->TRISE = i2c_MHz + 1;
// Enable the I2C master mode
s->CR1 |= I2C_CR1_PE; // Enable I2C
// Setting bus idle mode and wait for sync
}
/***************************************************************************
@ -198,42 +237,23 @@ void I2CManagerClass::I2C_sendStart() {
// Set counters here in case this is a retry.
rxCount = txCount = 0;
uint8_t temp;
// On a single-master I2C bus, the start bit won't be sent until the bus
// state goes to IDLE so we can request it without waiting. On a
// multi-master bus, the bus may be BUSY under control of another master,
// in which case we can avoid some arbitration failures by waiting until
// the bus state is IDLE. We don't do that here.
//while (s->SR2 & I2C_SR2_BUSY) {}
// If anything to send, initiate write. Otherwise initiate read.
if (operation == OPERATION_READ || ((operation == OPERATION_REQUEST) && !bytesToSend))
{
// Send start for read operation
s->CR1 |= I2C_CR1_ACK; // Enable the ACK
s->CR1 |= I2C_CR1_START; // Generate START
// Send address with read flag (1) or'd in
s->DR = (deviceAddress << 1) | 1; // send the address
while (!(s->SR1 && I2C_SR1_ADDR)); // wait for ADDR bit to set
// Special case for 1 byte reads!
if (bytesToReceive == 1)
{
s->CR1 &= ~I2C_CR1_ACK; // clear the ACK bit
temp = I2C1->SR1 | I2C1->SR2; // read SR1 and SR2 to clear the ADDR bit.... EV6 condition
s->CR1 |= I2C_CR1_STOP; // Stop I2C
}
else
temp = s->SR1 | s->SR2; // read SR1 and SR2 to clear the ADDR bit
}
else {
// Send start for write operation
s->CR1 |= I2C_CR1_ACK; // Enable the ACK
s->CR1 |= I2C_CR1_START; // Generate START
// Send address with write flag (0) or'd in
s->DR = (deviceAddress << 1) | 0; // send the address
while (!(s->SR1 && I2C_SR1_ADDR)); // wait for ADDR bit to set
temp = s->SR1 | s->SR2; // read SR1 and SR2 to clear the ADDR bit
}
// Check there's no STOP still in progress. If we OR the START bit into CR1
// and the STOP bit is already set, we could output multiple STOP conditions.
while (s->CR1 & I2C_CR1_STOP) {} // Wait for STOP bit to reset
s->CR2 |= (I2C_CR2_ITEVTEN | I2C_CR2_ITERREN); // Enable interrupts
s->CR2 &= ~I2C_CR2_ITBUFEN; // Don't enable buffer interupts yet.
s->CR1 &= ~I2C_CR1_POS; // Clear the POS bit
s->CR1 |= (I2C_CR1_ACK | I2C_CR1_START); // Enable the ACK and generate START
transactionState = TS_START;
}
/***************************************************************************
@ -252,9 +272,11 @@ void I2CManagerClass::I2C_close() {
s->CR1 &= ~I2C_CR1_PE; // Disable I2C peripheral
// Should never happen, but wait for up to 500us only.
unsigned long startTime = micros();
while ((s->CR1 && I2C_CR1_PE) != 0) {
if (micros() - startTime >= 500UL) break;
while ((s->CR1 & I2C_CR1_PE) != 0) {
if ((int32_t)(micros() - startTime) >= 500) break;
}
NVIC_DisableIRQ(I2C1_EV_IRQn);
NVIC_DisableIRQ(I2C1_ER_IRQn);
}
/***************************************************************************
@ -263,50 +285,217 @@ void I2CManagerClass::I2C_close() {
* (and therefore, indirectly, from I2CRB::wait() and I2CRB::isBusy()).
***************************************************************************/
void I2CManagerClass::I2C_handleInterrupt() {
volatile uint16_t temp_sr1, temp_sr2;
if (s->SR1 && I2C_SR1_ARLO) {
// Arbitration lost, restart
I2C_sendStart(); // Reinitiate request
} else if (s->SR1 && I2C_SR1_BERR) {
// Bus error
completionStatus = I2C_STATUS_BUS_ERROR;
state = I2C_STATE_COMPLETED;
} else if (s->SR1 && I2C_SR1_TXE) {
// Master write completed
if (s->SR1 && (1<<10)) {
// Nacked, send stop.
I2C_sendStop();
temp_sr1 = s->SR1;
// Check for errors first
if (temp_sr1 & (I2C_SR1_AF | I2C_SR1_ARLO | I2C_SR1_BERR)) {
// Check which error flag is set
if (temp_sr1 & I2C_SR1_AF)
{
s->SR1 &= ~(I2C_SR1_AF); // Clear AF
I2C_sendStop(); // Clear the bus
transactionState = TS_IDLE;
completionStatus = I2C_STATUS_NEGATIVE_ACKNOWLEDGE;
state = I2C_STATE_COMPLETED;
} else if (bytesToSend) {
// Acked, so send next byte
s->DR = sendBuffer[txCount++];
bytesToSend--;
} else if (bytesToReceive) {
// Last sent byte acked and no more to send. Send repeated start, address and read bit.
// s->I2CM.ADDR.bit.ADDR = (deviceAddress << 1) | 1;
} else {
// Check both TxE/BTF == 1 before generating stop
while (!(s->SR1 && I2C_SR1_TXE)); // Check TxE
while (!(s->SR1 && I2C_SR1_BTF)); // Check BTF
// No more data to send/receive. Initiate a STOP condition and finish
I2C_sendStop();
}
else if (temp_sr1 & I2C_SR1_ARLO)
{
// Arbitration lost, restart
s->SR1 &= ~(I2C_SR1_ARLO); // Clear ARLO
I2C_sendStart(); // Reinitiate request
transactionState = TS_START;
}
else if (temp_sr1 & I2C_SR1_BERR)
{
// Bus error
s->SR1 &= ~(I2C_SR1_BERR); // Clear BERR
I2C_sendStop(); // Clear the bus
transactionState = TS_IDLE;
completionStatus = I2C_STATUS_BUS_ERROR;
state = I2C_STATE_COMPLETED;
}
} else if (s->SR1 && I2C_SR1_RXNE) {
// Master read completed without errors
if (bytesToReceive == 1) {
// s->I2CM.CTRLB.bit.ACKACT = 1; // NAK final byte
I2C_sendStop(); // send stop
receiveBuffer[rxCount++] = s->DR; // Store received byte
bytesToReceive = 0;
}
else {
// No error flags, so process event according to current state.
switch (transactionState) {
case TS_START:
if (temp_sr1 & I2C_SR1_SB) {
// Event EV5
// Start bit has been sent successfully and we have the bus.
// If anything to send, initiate write. Otherwise initiate read.
if (operation == OPERATION_READ || ((operation == OPERATION_REQUEST) && !bytesToSend)) {
// Send address with read flag (1) or'd in
s->DR = (deviceAddress << 1) | 1; // send the address
transactionState = TS_R_ADDR;
} else {
// Send address with write flag (0) or'd in
s->DR = (deviceAddress << 1) | 0; // send the address
transactionState = TS_W_ADDR;
}
}
// SB bit is cleared by writing to DR (already done).
break;
case TS_W_ADDR:
if (temp_sr1 & I2C_SR1_ADDR) {
temp_sr2 = s->SR2; // read SR2 to complete clearing the ADDR bit
// Event EV6
// Address sent successfully, device has ack'd in response.
if (!bytesToSend) {
I2C_sendStop();
transactionState = TS_IDLE;
completionStatus = I2C_STATUS_OK;
state = I2C_STATE_COMPLETED;
} else if (bytesToReceive) {
// s->I2CM.CTRLB.bit.ACKACT = 0; // ACK all but final byte
} else {
// Put one byte into DR to load shift register.
s->DR = sendBuffer[txCount++];
bytesToSend--;
if (bytesToSend) {
// Put another byte to load DR
s->DR = sendBuffer[txCount++];
bytesToSend--;
}
if (!bytesToSend) {
// No more bytes to send.
// The TXE interrupt occurs when the DR is empty, and the BTF interrupt
// occurs when the shift register is also empty (one character later).
// To avoid repeated TXE interrupts during this time, we disable TXE interrupt.
s->CR2 &= ~I2C_CR2_ITBUFEN; // Wait for BTF interrupt, disable TXE interrupt
transactionState = TS_W_STOP;
} else {
// More data remaining to send after this interrupt, enable TXE interrupt.
s->CR2 |= I2C_CR2_ITBUFEN;
transactionState = TS_W_DATA;
}
}
}
break;
case TS_W_DATA:
if (temp_sr1 & I2C_SR1_TXE) {
// Event EV8_1/EV8
// Transmitter empty, write a byte to it.
if (bytesToSend) {
s->DR = sendBuffer[txCount++];
bytesToSend--;
if (!bytesToSend) {
s->CR2 &= ~I2C_CR2_ITBUFEN; // Disable TXE interrupt
transactionState = TS_W_STOP;
}
}
}
break;
case TS_W_STOP:
if (temp_sr1 & I2C_SR1_BTF) {
// Event EV8_2
// Done, last character sent. Anything to receive?
if (bytesToReceive) {
I2C_sendStart();
// NOTE: Three redundant BTF interrupts take place between the
// first BTF interrupt and the START interrupt. I've tried all sorts
// of ways to eliminate them, and the only thing that worked for
// me was to loop until the BTF bit becomes reset. Either way,
// it's a waste of processor time. Anyone got a solution?
//while (s->SR1 && I2C_SR1_BTF) {}
transactionState = TS_START;
} else {
I2C_sendStop();
transactionState = TS_IDLE;
completionStatus = I2C_STATUS_OK;
state = I2C_STATE_COMPLETED;
}
s->SR1 &= I2C_SR1_BTF; // Clear BTF interrupt
}
break;
case TS_R_ADDR:
if (temp_sr1 & I2C_SR1_ADDR) {
// Event EV6
// Address sent for receive.
// The next bit is different depending on whether there are
// 1 byte, 2 bytes or >2 bytes to be received, in accordance with the
// Programmers Reference RM0390.
if (bytesToReceive == 1) {
// Receive 1 byte
s->CR1 &= ~I2C_CR1_ACK; // Disable ack
temp_sr2 = s->SR2; // read SR2 to complete clearing the ADDR bit
// Next step will occur after a RXNE interrupt, so enable it
s->CR2 |= I2C_CR2_ITBUFEN;
transactionState = TS_R_STOP;
} else if (bytesToReceive == 2) {
// Receive 2 bytes
s->CR1 &= ~I2C_CR1_ACK; // Disable ACK for final byte
s->CR1 |= I2C_CR1_POS; // set POS flag to delay effect of ACK flag
// Next step will occur after a BTF interrupt, so disable RXNE interrupt
s->CR2 &= ~I2C_CR2_ITBUFEN;
temp_sr2 = s->SR2; // read SR2 to complete clearing the ADDR bit
transactionState = TS_R_STOP;
} else {
// >2 bytes, just wait for bytes to come in and ack them for the time being
// (ack flag has already been set).
// Next step will occur after a BTF interrupt, so disable RXNE interrupt
s->CR2 &= ~I2C_CR2_ITBUFEN;
temp_sr2 = s->SR2; // read SR2 to complete clearing the ADDR bit
transactionState = TS_R_DATA;
}
}
break;
case TS_R_DATA:
// Event EV7/EV7_1
if (temp_sr1 & I2C_SR1_BTF) {
// Byte received in receiver - read next byte
if (bytesToReceive == 3) {
// Getting close to the last byte, so a specific sequence is recommended.
s->CR1 &= ~I2C_CR1_ACK; // Reset ack for next byte received.
transactionState = TS_R_STOP;
}
receiveBuffer[rxCount++] = s->DR; // Store received byte
bytesToReceive--;
}
break;
case TS_R_STOP:
if (temp_sr1 & I2C_SR1_BTF) {
// Event EV7 (last one)
// When we've got here, the receiver has got the last two bytes
// (or one byte, if only one byte is being received),
// and NAK has already been sent, so we need to read from the receiver.
if (bytesToReceive) {
if (bytesToReceive > 1)
I2C_sendStop();
while(bytesToReceive) {
receiveBuffer[rxCount++] = s->DR; // Store received byte(s)
bytesToReceive--;
}
// Finish.
transactionState = TS_IDLE;
completionStatus = I2C_STATUS_OK;
state = I2C_STATE_COMPLETED;
}
} else if (temp_sr1 & I2C_SR1_RXNE) {
if (bytesToReceive == 1) {
// One byte on a single-byte transfer. Ack has already been set.
I2C_sendStop();
receiveBuffer[rxCount++] = s->DR; // Store received byte
bytesToReceive--;
// Finish.
transactionState = TS_IDLE;
completionStatus = I2C_STATUS_OK;
state = I2C_STATE_COMPLETED;
} else
s->SR1 &= I2C_SR1_RXNE; // Acknowledge interrupt
}
break;
}
// If we've received an interrupt at any other time, we're not interested so clear it
// to prevent it recurring ad infinitum.
s->SR1 = 0;
}
}
#endif /* I2CMANAGER_STM32_H */

6
defines.h
View File

@ -144,9 +144,9 @@
#define DISABLE_EEPROM
#endif
// STM32 support for native I2C is awaiting development
#ifndef I2C_USE_WIRE
#define I2C_USE_WIRE
#endif
// #ifndef I2C_USE_WIRE
// #define I2C_USE_WIRE
// #endif
/* TODO when ready
#elif defined(ARDUINO_ARCH_RP2040)