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This commit is contained in:
yelvlab
2026-02-18 17:44:38 +08:00
parent d324d5f92a
commit 7419dec1b5
14 changed files with 1076 additions and 281 deletions
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689
Src/i2c.c
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@@ -34,6 +34,7 @@ void i2c_gpio_config(void) {
i2c_result_t i2c_config(void) {
/* configure I2C GPIO */
i2c_gpio_config();
/* enable I2C clock */
rcu_periph_clock_enable(RCU_I2C);
/* configure I2C clock */
@@ -90,10 +91,6 @@ i2c_result_t i2c_bus_reset(void) {
gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN); /* release SCL */
gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN); /* release SDA */
#ifdef DEBUG_VERBOSE
printf("I2C bus reset: SCL = %d, SDA = %d\r\n", gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN), gpio_input_bit_get(I2C_SDA_PORT, I2C_SDA_PIN));
#endif
/* 3. Double sample to confirm bus state */
delay_10us(1);
bool scl_value1 = gpio_input_bit_get(I2C_SCL_PORT, I2C_SCL_PIN);
@@ -104,27 +101,18 @@ i2c_result_t i2c_bus_reset(void) {
/* 4. If SCL low -> stuck (cannot proceed) */
if (!scl_value2) {
#ifdef DEBUG_VERBOSE
printf("I2C bus reset: SCL stuck low\r\n");
#endif
return I2C_RECOVERY_SCL_STUCK_LOW;
}
/* 5. Fast path: bus idle */
if (scl_value1 && sda_value1 && scl_value2 && sda_value2) {
i2c_config();
#ifdef DEBUG_VERBOSE
printf("I2C bus reset: bus idle\r\n");
#endif
return I2C_RECOVERY_OK;
}
/* 6. SDA low: attempt to free by generating up to I2C_RECOVERY_CLOCKS pulses */
if (scl_value2 && !sda_value2) {
bool sda_released = false;
#ifdef DEBUG_VERBOSE
printf("I2C bus reset: SCL will try to free SDA\r\n");
#endif
for (uint8_t i = 0; i < I2C_RECOVERY_CLOCKS && !sda_released; i++) {
if (!i2c_generate_scl_pulse()) {
return I2C_RECOVERY_SCL_STUCK_LOW; /* SCL failed to go high */
@@ -137,9 +125,6 @@ i2c_result_t i2c_bus_reset(void) {
return I2C_RECOVERY_SDA_STUCK_LOW;
}
/* 7. Generate a STOP condition to leave bus in idle state */
#ifdef DEBUG_VERBOSE
printf("I2C bus reset: generating STOP condition\r\n");
#endif
gpio_bit_reset(I2C_SDA_PORT, I2C_SDA_PIN); /* SDA low */
delay_10us(1);
gpio_bit_set(I2C_SCL_PORT, I2C_SCL_PIN); /* ensure SCL high */
@@ -147,10 +132,7 @@ i2c_result_t i2c_bus_reset(void) {
gpio_bit_set(I2C_SDA_PORT, I2C_SDA_PIN); /* SDA rising while SCL high -> STOP */
delay_10us(1);
}
#ifdef DEBUG_VERBOSE
printf("I2C bus reset: bus recovered\r\n");
#endif
/* 8. Reconfigure & enable peripheral */
i2c_config();
return I2C_RECOVERY_OK;
@@ -171,10 +153,10 @@ void i2c_scan(void) {
// printf("Scanning I2C bus...\r\n");
const char* msg1 = "Scanning I2C bus...\r\n";
for (uint8_t i = 0; msg1[i] != '\0'; i++) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, msg1[i]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, msg1[i]);
}
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
while (usart_flag_get(UART_PHY, USART_FLAG_TC) == RESET) {}
for (address = 1; address < 127; address++) {
timeout = 0;
@@ -197,30 +179,35 @@ void i2c_scan(void) {
i2c_master_addressing(I2C0, (address << 1), I2C_TRANSMITTER);
timeout = 0;
// 等待地址发送完成
while (!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND) && (timeout < I2C_TIME_OUT))
// 等待地址发送完成或错误
while (!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND) && !i2c_flag_get(I2C0, I2C_FLAG_AERR) && (timeout < I2C_TIME_OUT))
timeout++;
if (timeout < I2C_TIME_OUT) {
if (timeout < I2C_TIME_OUT && i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)) {
// 设备响应 - 清除地址标志
i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
// printf("Found device at 0x%02X\r\n", address);
const char* msg2_prefix = "Found device at 0x";
for (uint8_t i = 0; msg2_prefix[i] != '\0'; i++) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, msg2_prefix[i]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, msg2_prefix[i]);
}
// 发送地址的十六进制表示
uint8_t hex_chars[] = "0123456789ABCDEF";
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, hex_chars[(address >> 4) & 0x0F]);
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, hex_chars[address & 0x0F]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, hex_chars[(address >> 4) & 0x0F]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, hex_chars[address & 0x0F]);
const char* msg2_suffix = "\r\n";
for (uint8_t i = 0; msg2_suffix[i] != '\0'; i++) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, msg2_suffix[i]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, msg2_suffix[i]);
}
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
while (usart_flag_get(UART_PHY, USART_FLAG_TC) == RESET) {}
found_devices++;
} else if (i2c_flag_get(I2C0, I2C_FLAG_AERR)) {
// 设备无响应 - 清除错误标志
i2c_flag_clear(I2C0, I2C_FLAG_AERR);
}
// 生成停止条件
@@ -236,33 +223,80 @@ void i2c_scan(void) {
// printf("No I2C devices found.\r\n");
const char* msg3 = "No I2C devices found.\r\n";
for (uint8_t i = 0; msg3[i] != '\0'; i++) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, msg3[i]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, msg3[i]);
}
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
while (usart_flag_get(UART_PHY, USART_FLAG_TC) == RESET) {}
} else {
// printf("Total %d I2C devices found.\r\n", found_devices);
const char* msg4_prefix = "Total ";
for (uint8_t i = 0; msg4_prefix[i] != '\0'; i++) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, msg4_prefix[i]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, msg4_prefix[i]);
}
// 发送设备数量
if (found_devices >= 10) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, '0' + (found_devices / 10));
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, '0' + (found_devices / 10));
}
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, '0' + (found_devices % 10));
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, '0' + (found_devices % 10));
const char* msg4_suffix = " I2C devices found.\r\n";
for (uint8_t i = 0; msg4_suffix[i] != '\0'; i++) {
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(I2C_DEBUG_UART, msg4_suffix[i]);
while (usart_flag_get(UART_PHY, USART_FLAG_TBE) == RESET) {}
usart_data_transmit(UART_PHY, msg4_suffix[i]);
}
while (usart_flag_get(I2C_DEBUG_UART, USART_FLAG_TC) == RESET) {}
while (usart_flag_get(UART_PHY, USART_FLAG_TC) == RESET) {}
}
}
/**
* @brief 内部辅助函数：等待指定的I2C标志位被设置，带有超时。
* @param[in] flag: 要等待的I2C事件标志。
* @retval i2c_result_t: I2C_RESULT_SUCCESS 或 I2C_RESULT_TIMEOUT。
*/
static i2c_result_t _i2c_wait_flag_timeout(uint32_t flag)
{
uint16_t timeout = 0;
while(!i2c_flag_get(I2C0, flag)){
if(timeout++ > I2C_TIME_OUT){
#ifdef DEBUG_VERBOSE
const char* fname = "UNKNOWN";
switch (flag) {
case I2C_FLAG_SBSEND: fname = "SBSEND"; break;
case I2C_FLAG_ADDSEND: fname = "ADDSEND"; break;
case I2C_FLAG_TBE: fname = "TBE"; break;
case I2C_FLAG_RBNE: fname = "RBNE"; break;
case I2C_FLAG_BTC: fname = "BTC"; break;
case I2C_FLAG_AERR: fname = "AERR"; break;
case I2C_FLAG_BERR: fname = "BERR"; break;
case I2C_FLAG_LOSTARB: fname = "LOSTARB"; break;
case I2C_FLAG_I2CBSY: fname = "I2CBSY"; break;
}
printf("I2C wait flag timeout: flag=0x%08X (%s)\r\n", (unsigned int)flag, fname);
#endif
return I2C_RESULT_TIMEOUT;
}
}
return I2C_RESULT_SUCCESS;
}
/**
* @brief 内部辅助函数：等待指定的I2C标志位被清除，带有超时。
* @param[in] flag: 要等待的I2C事件标志。
* @retval i2c_result_t: I2C_RESULT_SUCCESS 或 I2C_RESULT_TIMEOUT。
*/
static i2c_result_t _i2c_wait_flag_clear_timeout(uint32_t flag)
{
uint16_t timeout = 0;
while(i2c_flag_get(I2C0, flag)){
if(timeout++ > I2C_TIME_OUT){
return I2C_RESULT_TIMEOUT;
}
}
return I2C_RESULT_SUCCESS;
}
i2c_result_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data[2]) {
i2c_state_t state = I2C_STATE_START;
uint16_t timeout = 0;
@@ -325,7 +359,7 @@ i2c_result_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data
} else {
i2c_flag_clear(I2C0, I2C_FLAG_AERR);
timeout =0;
#ifdef DEBUG_VERBOES
#ifdef DEBUG_VERBOSE
printf("IIC write failed for Error Slave Address. \n");
#endif
return I2C_RESULT_NACK;
@@ -333,39 +367,28 @@ i2c_result_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data
case I2C_STATE_TRANSMIT_REG:
/* wait until the transmit data buffer is empty */
while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send register address */
i2c_data_transmit(I2C0, reg_addr);
timeout = 0;
state = I2C_STATE_TRANSMIT_DATA;
break;
case I2C_STATE_TRANSMIT_DATA:
/* wait until the transmit data buffer is empty */
while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send register MSB value */
i2c_data_transmit(I2C0, data[0]);
timeout = 0;
/* wait until the transmit data buffer is empty */
while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -381,13 +404,9 @@ i2c_result_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data
/* send register LSB value */
i2c_data_transmit(I2C0, data[1]);
timeout = 0;
/* wait until BTC bit is set */
while (!i2c_flag_get(I2C0, I2C_FLAG_BTC) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -413,25 +432,13 @@ i2c_result_t i2c_write_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t data
return I2C_RESULT_SUCCESS;
case I2C_STATE_ERROR:
/* send a stop condition to I2C bus */
i2c_stop_on_bus(I2C0);
timeout = 0;
while ((I2C_CTL0(I2C0) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
return I2C_RESULT_ERROR;
}
i2c_flag_clear(I2C0, I2C_FLAG_AERR);
i2c_flag_clear(I2C0, I2C_FLAG_BERR);
i2c_flag_clear(I2C0, I2C_FLAG_LOSTARB);
/* I2C bus error, try to reset the bus and retry */
i2c_bus_reset();
retry_count ++;
if (retry_count >= I2C_MAX_RETRY)
{
#ifdef DEBUG_VERBOES
#ifdef DEBUG_VERBOSE
printf("IIC write failed after %d retries\n", I2C_MAX_RETRY);
#endif
return I2C_RESULT_ERROR;
@@ -472,11 +479,8 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
case I2C_STATE_START:
timeout = 0;
// wait for bus to be idle
while (i2c_flag_get(I2C0, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
/* wait for bus to be idle */
if(_i2c_wait_flag_clear_timeout(I2C_FLAG_I2CBSY) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -484,15 +488,11 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
// send start condition
i2c_start_on_bus(I2C0);
state = I2C_STATE_SEND_ADDRESS;
timeout = 0;
break;
case I2C_STATE_SEND_ADDRESS:
/* wait for start condition to be sent */
while ((!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_SBSEND) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -540,10 +540,7 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
case I2C_STATE_TRANSMIT_DATA:
/* wait for transmit buffer to be empty */
while ((!i2c_flag_get(I2C0, I2C_FLAG_TBE)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -551,15 +548,11 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
/* send register address */
i2c_data_transmit(I2C0, reg_addr);
state = I2C_STATE_RESTART;
timeout = 0;
break;
case I2C_STATE_RESTART:
/* wait for byte transfer complete BTC: Bit Transfer Complete */
while ((!i2c_flag_get(I2C0, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -568,11 +561,7 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
i2c_start_on_bus(I2C0);
/* wait for repeated start condition to be sent */
timeout = 0;
while ((!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_SBSEND) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -588,10 +577,7 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
case I2C_STATE_RECEIVE_DATA:
/* Wait for BTC (both bytes received) */
while ((!i2c_flag_get(I2C0, I2C_FLAG_BTC)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
@@ -621,13 +607,13 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
return I2C_RESULT_SUCCESS;
case I2C_STATE_ERROR:
/* send stop condition to release bus */
i2c_stop_on_bus(I2C0);
/* I2C bus error, try to reset the bus and retry */
i2c_bus_reset();
retry_count++;
if (retry_count >= I2C_MAX_RETRY) {
#ifdef DEBUG_VERBOES
printf("IIC read failed after %d retries\n", I2C_RETRY_MAX);
#ifdef DEBUG_VERBOSE
printf("IIC read failed after %d retries\n", I2C_MAX_RETRY);
#endif
return I2C_RESULT_ERROR;
}
@@ -649,6 +635,481 @@ i2c_result_t i2c_read_16bits(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data
return I2C_RESULT_TIMEOUT;
}
/*!
\brief write data to I2C device with configurable length
\param[in] slave_addr: slave device address (7-bit)
\param[in] reg_addr: register address
\param[in] data: pointer to data buffer
\param[in] length: number of bytes to write (1-255)
\param[out] none
\retval i2c_result_t: operation result
*/
i2c_result_t i2c_write(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data, uint8_t length) {
i2c_state_t state = I2C_STATE_START;
uint16_t timeout = 0;
uint8_t retry_count = 0;
uint8_t data_index = 0;
/* parameter validation */
if (data == NULL || slave_addr > 0x7F || length == 0) {
#ifdef DEBUG_VERBOSE
printf("I2C read invalid param: slave=0x%02X, len=%u, data=%p\r\n", slave_addr, length, data);
#endif
return I2C_RESULT_INVALID_PARAM;
}
while (retry_count < I2C_MAX_RETRY) {
switch (state) {
case I2C_STATE_START:
timeout = 0;
data_index = 0;
/* wait for bus to be idle */
while (i2c_flag_get(I2C0, I2C_FLAG_I2CBSY) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
state = I2C_STATE_ERROR;
break;
}
i2c_start_on_bus(I2C0);
timeout = 0;
state = I2C_STATE_SEND_ADDRESS;
break;
case I2C_STATE_SEND_ADDRESS:
/* wait for start condition to be sent. SBSEND flag */
while((!i2c_flag_get(I2C0, I2C_FLAG_SBSEND)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
state = I2C_STATE_ERROR;
break;
}
/* send slave address */
i2c_master_addressing(I2C0, slave_addr << 1, I2C_TRANSMITTER);
timeout = 0;
state = I2C_STATE_CLEAR_ADDRESS;
break;
case I2C_STATE_CLEAR_ADDRESS:
/* wait for address to be acknowledged.ADDSEND set means i2c slave sends ACK */
while ((!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)) && (!i2c_flag_get(I2C0, I2C_FLAG_AERR)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
state = I2C_STATE_ERROR;
break;
} else if (i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)) {
i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
timeout = 0;
state = I2C_STATE_TRANSMIT_REG;
break;
} else {
/* NACK received - address not acknowledged */
i2c_flag_clear(I2C0, I2C_FLAG_AERR);
i2c_stop_on_bus(I2C0);
timeout = 0;
#ifdef DEBUG_VERBOSE
printf("I2C write failed for Error Slave Address. \n");
#endif
return I2C_RESULT_NACK;
}
case I2C_STATE_TRANSMIT_REG:
/* wait until the transmit data buffer is empty */
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send register address */
i2c_data_transmit(I2C0, reg_addr);
state = I2C_STATE_TRANSMIT_DATA;
break;
case I2C_STATE_TRANSMIT_DATA:
/* wait until the transmit data buffer is empty */
while (data_index < length) {
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send data byte */
i2c_data_transmit(I2C0, data[data_index]);
data_index++;
/* check for errors */
if (i2c_flag_get(I2C0, I2C_FLAG_AERR)) {
i2c_stop_on_bus(I2C0);
return I2C_RESULT_NACK;
} else if (i2c_flag_get(I2C0, I2C_FLAG_BERR) || i2c_flag_get(I2C0, I2C_FLAG_LOSTARB)) {
i2c_stop_on_bus(I2C0);
return I2C_RESULT_ERROR;
}
}
if(state == I2C_STATE_ERROR) break;
/* check if all data has been sent */
if (data_index >= length) {
/* wait until BTC bit is set for last byte */
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
state = I2C_STATE_STOP;
}
break;
case I2C_STATE_STOP:
/* send a stop condition to I2C bus */
i2c_stop_on_bus(I2C0);
timeout = 0;
while ((I2C_CTL0(I2C0) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
state = I2C_STATE_ERROR;
break;
}
/* success */
return I2C_RESULT_SUCCESS;
case I2C_STATE_ERROR:
/* I2C bus error, try to reset the bus and retry */
i2c_bus_reset();
retry_count++;
if (retry_count >= I2C_MAX_RETRY) {
#ifdef DEBUG_VERBOSE
printf("IIC write failed after %d retries\n", I2C_MAX_RETRY);
#endif
return I2C_RESULT_ERROR;
}
/* reset state machine for retry */
state = I2C_STATE_START;
timeout = 0;
/* small delay before retry */
delay_10us(10);
break;
default:
state = I2C_STATE_START;
break;
}
}
return I2C_RESULT_TIMEOUT;
}
/*!
\brief read data from I2C device with configurable length
\param[in] slave_addr: slave device address (7-bit)
\param[in] reg_addr: register address
\param[out] data: pointer to data buffer
\param[in] length: number of bytes to read (1-255)
\retval i2c_result_t: operation result
*/
i2c_result_t i2c_read(uint8_t slave_addr, uint8_t reg_addr, uint8_t *data, uint8_t length) {
i2c_state_t state = I2C_STATE_START;
uint16_t timeout = 0;
uint8_t retry_count = 0;
bool write_phase = true;
uint8_t data_index = 0;
/* parameter validation */
if (data == NULL || slave_addr > 0x7F || length == 0) {
return I2C_RESULT_INVALID_PARAM;
}
/* enable acknowledge */
i2c_ack_config(I2C0, I2C_ACK_ENABLE);
#ifdef DEBUG_VERBOSE
printf("I2C read start: slave=0x%02X reg=0x%02X len=%u\r\n", slave_addr, reg_addr, length);
#endif
while (retry_count < (uint8_t)I2C_MAX_RETRY) {
switch (state) {
case I2C_STATE_START:
timeout = 0;
data_index = 0;
/* wait for bus to be idle */
if(_i2c_wait_flag_clear_timeout(I2C_FLAG_I2CBSY) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send start condition */
i2c_start_on_bus(I2C0);
state = I2C_STATE_SEND_ADDRESS;
break;
case I2C_STATE_SEND_ADDRESS:
/* wait for start condition to be sent */
if(_i2c_wait_flag_timeout(I2C_FLAG_SBSEND) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send slave address */
if (write_phase) {
/* write phase: send address with write bit */
i2c_master_addressing(I2C0, (slave_addr << 1), I2C_TRANSMITTER);
} else {
/* read phase: send address with read bit */
i2c_master_addressing(I2C0, (slave_addr << 1) | 0x01, I2C_RECEIVER);
}
state = I2C_STATE_CLEAR_ADDRESS;
timeout = 0;
break;
case I2C_STATE_CLEAR_ADDRESS:
/* wait for address to be acknowledged */
while ((!i2c_flag_get(I2C0, I2C_FLAG_ADDSEND)) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
state = I2C_STATE_ERROR;
break;
}
/* debug: show address ack and error flags */
#ifdef DEBUG_VERBOSE
printf("I2C CLEAR_ADDRESS: write_phase=%d ADDSEND=%d AERR=%d\r\n",
(int)write_phase,
(int)i2c_flag_get(I2C0, I2C_FLAG_ADDSEND),
(int)i2c_flag_get(I2C0, I2C_FLAG_AERR));
#endif
if (write_phase) {
/* clear address flag (write phase) */
i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
state = I2C_STATE_TRANSMIT_DATA;
} else {
/* READ phase: handle ACK/ACKPOS based on requested length
- length == 1: disable ACK before clearing ADDR
- length == 2: set ACKPOS_NEXT and disable ACK before clearing ADDR
- length > 2: keep ACK enabled and clear ADDR; we'll handle N-2/BTF sequence later */
if (length == 1) {
i2c_ack_config(I2C0, I2C_ACK_DISABLE);
#ifdef DEBUG_VERBOSE
printf("I2C READ phase: length=1, disabling ACK before clearing ADDSEND\r\n");
#endif
} else if (length == 2) {
i2c_ackpos_config(I2C0, I2C_ACKPOS_NEXT);
i2c_ack_config(I2C0, I2C_ACK_DISABLE);
#ifdef DEBUG_VERBOSE
printf("I2C READ phase: length=2, set ACKPOS_NEXT and disabling ACK before clearing ADDSEND\r\n");
#endif
} else {
/* length > 2: keep ACK enabled so slave will clock out data */
i2c_ack_config(I2C0, I2C_ACK_ENABLE);
#ifdef DEBUG_VERBOSE
printf("I2C READ phase: length=%u (>2), keeping ACK enabled\r\n", length);
#endif
}
/* now clear address flag to release SCL and enter data phase */
i2c_flag_clear(I2C0, I2C_FLAG_ADDSEND);
state = I2C_STATE_RECEIVE_DATA;
}
timeout = 0;
break;
case I2C_STATE_TRANSMIT_DATA:
/* wait for transmit buffer to be empty */
if(_i2c_wait_flag_timeout(I2C_FLAG_TBE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send register address */
i2c_data_transmit(I2C0, reg_addr);
state = I2C_STATE_RESTART;
break;
case I2C_STATE_RESTART:
/* wait for byte transfer complete */
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
#ifdef DEBUG_VERBOSE
printf("I2C RESTART: after BTC, delay 5ms and issuing repeated START\r\n");
#endif
/* small delay to allow slave device to prepare multi-byte data before repeated start */
/* increased to 5ms to improve reliability for DLPC multi-byte reads */
delay_ms(5);
/* generate repeated start condition */
i2c_start_on_bus(I2C0);
/* wait for repeated start condition to be sent */
if(_i2c_wait_flag_timeout(I2C_FLAG_SBSEND) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send slave address with read bit */
i2c_master_addressing(I2C0, (slave_addr << 1), I2C_RECEIVER);
/* switch to read phase */
write_phase = false;
state = I2C_STATE_CLEAR_ADDRESS;
timeout = 0;
#ifdef DEBUG_VERBOSE
printf("I2C addressing sent for read (slave=0x%02X)\r\n", slave_addr);
#endif
break;
case I2C_STATE_RECEIVE_DATA:
#ifdef DEBUG_VERBOSE
printf("I2C RECEIVE_DATA: expecting %u bytes\r\n", length);
#endif
if (length == 1) {
/* single byte read */
if(_i2c_wait_flag_timeout(I2C_FLAG_RBNE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
data[0] = i2c_data_receive(I2C0);
state = I2C_STATE_STOP;
} else if (length == 2) {
/* two bytes read */
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* send STOP before reading the last two bytes */
i2c_stop_on_bus(I2C0);
/* read the two bytes back-to-back */
data[0] = i2c_data_receive(I2C0);
data[1] = i2c_data_receive(I2C0);
state = I2C_STATE_STOP;
} else {
/* multi-byte read (length > 2) */
while (data_index < length) {
if (data_index < length - 2) {
/* normal bytes: wait for RBNE and read with ACK */
if(_i2c_wait_flag_timeout(I2C_FLAG_RBNE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
data[data_index] = i2c_data_receive(I2C0);
data_index++;
} else if (data_index == length - 2) {
/* second to last byte: wait for BTF, then disable ACK and read */
if(_i2c_wait_flag_timeout(I2C_FLAG_BTC) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* disable ACK before reading N-1 byte */
i2c_ack_config(I2C0, I2C_ACK_DISABLE);
/* send STOP before reading N-1 byte */
i2c_stop_on_bus(I2C0);
/* read N-1 byte */
data[data_index] = i2c_data_receive(I2C0);
data_index++;
} else {
/* last byte: wait for RBNE and read */
if(_i2c_wait_flag_timeout(I2C_FLAG_RBNE) != I2C_RESULT_SUCCESS) {
state = I2C_STATE_ERROR;
break;
}
/* read last byte */
data[data_index] = i2c_data_receive(I2C0);
data_index++;
}
}
if(state == I2C_STATE_ERROR) break;
state = I2C_STATE_STOP;
}
break;
case I2C_STATE_STOP:
/* wait for stop condition to complete */
while ((I2C_CTL0(I2C0) & I2C_CTL0_STOP) && (timeout < I2C_TIME_OUT)) {
timeout++;
}
if (timeout >= I2C_TIME_OUT) {
state = I2C_STATE_ERROR;
break;
}
/* reset ACK configuration for next operation */
i2c_ack_config(I2C0, I2C_ACK_ENABLE);
i2c_ackpos_config(I2C0, I2C_ACKPOS_CURRENT);
/* success */
return I2C_RESULT_SUCCESS;
case I2C_STATE_ERROR:
/* I2C bus error, try to reset the bus and retry */
#ifdef DEBUG_VERBOSE
printf("I2C_STATE_ERROR: resetting bus and retrying (retry_count=%u)\r\n", retry_count);
#endif
i2c_bus_reset();
/* reset ACK configuration */
i2c_ack_config(I2C0, I2C_ACK_ENABLE);
i2c_ackpos_config(I2C0, I2C_ACKPOS_CURRENT);
retry_count++;
if (retry_count >= I2C_MAX_RETRY) {
#ifdef DEBUG_VERBOSE
/* Print diagnostic flags to help root-cause analysis */
printf("I2C read final failure after %d retries, last_state=%d\r\n", I2C_MAX_RETRY, state);
printf(" FLAGS: AERR=%d BERR=%d LOSTARB=%d I2CBSY=%d\r\n",
(int)i2c_flag_get(I2C0, I2C_FLAG_AERR),
(int)i2c_flag_get(I2C0, I2C_FLAG_BERR),
(int)i2c_flag_get(I2C0, I2C_FLAG_LOSTARB),
(int)i2c_flag_get(I2C0, I2C_FLAG_I2CBSY));
#endif
#ifdef DEBUG_VERBOSE
printf("I2C read failed after %d retries\n", I2C_MAX_RETRY);
#endif
return I2C_RESULT_ERROR;
}
/* reset state machine for retry */
state = I2C_STATE_START;
write_phase = true;
timeout = 0;
/* small delay before retry */
delay_10us(10);
break;
default:
state = I2C_STATE_START;
break;
}
}
/* timeout path: provide debug info */
#ifdef DEBUG_VERBOSE
printf("I2C read timeout (end state). slave=0x%02X, len=%u\r\n", slave_addr, length);
printf(" FLAGS: AERR=%d BERR=%d LOSTARB=%d I2CBSY=%d\r\n",
(int)i2c_flag_get(I2C0, I2C_FLAG_AERR),
(int)i2c_flag_get(I2C0, I2C_FLAG_BERR),
(int)i2c_flag_get(I2C0, I2C_FLAG_LOSTARB),
(int)i2c_flag_get(I2C0, I2C_FLAG_I2CBSY));
#endif
return I2C_RESULT_TIMEOUT;
}
#ifdef DEBUG_VERBOSE
/*!
\brief get status string for debugging