Hi,
I am trying to connect raspberry Pi with STM32 via I2C.. for 2 weeks now.. going to the specifics: RPI3 is a master, STM32 is a slave, I use HAL library and CubeMX. All communication should be the simplest possible. I want to send / receive one byte - nothing more. I have connected a logic analyzer and UART console for debugging purposes.
Maybe I'll show my code first.
Init I2C:
/* I2C2 init function */
void MX_I2C2_Init(void)
{
hi2c2.Instance = I2C2;
hi2c2.Init.ClockSpeed = 62500;
hi2c2.Init.DutyCycle = I2C_DUTYCYCLE_2;
hi2c2.Init.OwnAddress1 = 32;
hi2c2.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c2.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c2.Init.OwnAddress2 = 0;
hi2c2.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c2.Init.NoStretchMode = I2C_NOSTRETCH_ENABLE;
if (HAL_I2C_Init(&hi2c2) != HAL_OK)
{
Error_Handler();
}
}
void HAL_I2C_MspInit(I2C_HandleTypeDef* i2cHandle)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
if(i2cHandle->Instance==I2C1)
{
/* USER CODE BEGIN I2C1_MspInit 0 */
/* USER CODE END I2C1_MspInit 0 */
__HAL_RCC_GPIOB_CLK_ENABLE();
/**I2C1 GPIO Configuration
PB6 ------> I2C1_SCL
PB7 ------> I2C1_SDA
*/
GPIO_InitStruct.Pin = SCL_EEPROM_Pin|SDA_EEPROM_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* I2C1 clock enable */
__HAL_RCC_I2C1_CLK_ENABLE();
/* USER CODE BEGIN I2C1_MspInit 1 */
/* USER CODE END I2C1_MspInit 1 */
}
else if(i2cHandle->Instance==I2C2)
{
/* USER CODE BEGIN I2C2_MspInit 0 */
/* USER CODE END I2C2_MspInit 0 */
__HAL_RCC_GPIOB_CLK_ENABLE();
/**I2C2 GPIO Configuration
PB10 ------> I2C2_SCL
PB11 ------> I2C2_SDA
*/
GPIO_InitStruct.Pin = SCL_RP3_Pin|SDA_RP3_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_AF_OD;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_MEDIUM;
HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
/* I2C2 clock enable */
__HAL_RCC_I2C2_CLK_ENABLE();
/* I2C2 interrupt Init */
HAL_NVIC_SetPriority(I2C2_EV_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(I2C2_EV_IRQn);
HAL_NVIC_SetPriority(I2C2_ER_IRQn, 0, 0);
HAL_NVIC_EnableIRQ(I2C2_ER_IRQn);
/* USER CODE BEGIN I2C2_MspInit 1 */
/* USER CODE END I2C2_MspInit 1 */
}
}All Callbacks:
void HAL_I2C_AddrCallback(I2C_HandleTypeDef *hi2c, uint8_t TransferDirection, uint16_t AddrMatchCode)
{
debug_tx("HAL_I2C_AddrCallback\r\n");
UNUSED(hi2c);
//UNUSED(TransferDirection);
UNUSED(AddrMatchCode);
if(TransferDirection)
{
RPI_State = API_RPI_TO_STM;
debug_tx("DIR: RPI_TO_STM\r\n");
}
else
{
RPI_State = API_STM_TO_RPI;
debug_tx("DIR: STM_TO_RPI\r\n");
}
}
void HAL_I2C_ListenCpltCallback(I2C_HandleTypeDef *hi2c)
{
/* Prevent unused argument(s) compilation warning */
UNUSED(hi2c);
debug_tx("HAL_I2C_ListenCpltCallback\r\n");
if(RPI_State == API_RPI_TO_STM)
{
if (HAL_I2C_Slave_Receive_IT(&hi2c2, rx_buf, 1) != HAL_OK)
{
Error_Handler();
}
}
else if(RPI_State == API_STM_TO_RPI)
{
lcd_string(4, 0, "SLAVE TX 1 ");
if (HAL_I2C_Slave_Transmit_IT(&hi2c2, tx_buf, 1) != HAL_OK)
{
Error_Handler();
lcd_string(5, 0, "SLAVE TX ER");
}
}
}
void HAL_I2C_SlaveTxCpltCallback(I2C_HandleTypeDef *hi2c)
{
debug_tx("HAL_I2C_SlaveTxCpltCallback\r\n");
}
void HAL_I2C_SlaveRxCpltCallback(I2C_HandleTypeDef *hi2c)
{
debug_tx("HAL_I2C_SlaveRxCpltCallback\r\n");
lcd_hex(5, 0, rx_buf[0]);
HAL_I2C_EnableListen_IT(&hi2c2); // Restart
}
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
debug_tx("Error_Handler\r\n");
/* USER CODE END Error_Handler_Debug */
}When RPI sends:
in the console I can see:
Doesn't enter "HAL_I2C_SlaveRxCpltCallback". If RPI sends an identical frame a second time then it goes into "HAL_I2C_SlaveRxCpltCallback".
Byte reception works every second time.
When I want to send some byte to RPI3 it's even worse. The frame looks like this:
From RPI's point of view, I'm only sending an address and waiting for 1 byte. I have no idea why STM sends these 2 bytes back. When we look at the console:
You can see that it enters only the "HAL_I2C_AddrCallback". And it misreads the direction flag.
When I change "NoStretchMode" to DISABLE it's even worse. It is only better that it reads the direction flag correctly.
Do you have any idea what I'm doing wrong? Or maybe there are some bugs in HAL? I really got stuck. I will be veery grateful for any help.
Best regards,
Sebastian
