STM32G474RET
The response is shifted by 3 bytes, the first 3 bytes are invalid, the 4th and following bytes are correct every SPI communication.
I cannot figure out how to solve the 3 bytes shift.
This is the code now and a situation sketch.
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_DMA_Init();
MX_LPUART1_UART_Init();
MX_USART1_UART_Init();
MX_CRC_Init();
MX_I2C1_Init();
MX_SPI2_Init();
RetargetInit(&hlpuart1);
spi_buf_out[0]=1;
spi_buf_out[1]=2;
spi_buf_out[2]=3;
spi_buf_out[3]=4;
HAL_SPI_TransmitReceive_DMA(&hspi2,spi_buf_out,spi_buf_in,SPI_SIZE);
}
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin){
if(GPIO_Pin == GPIO_PIN_12){
WritePin(PA10,1); //DE
memcpy(uart_buf_out,spi_buf_in,SPI_SIZE);
HAL_UART_Transmit_DMA(&huart1,(uint8_t *)(uart_buf_out+1),*(uint8_t *)(uart_buf_out));
}
}
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart){
volatile HAL_StatusTypeDef status;
if(huart == &huart1){
WritePin(PA10,0); //DE
status = HAL_UARTEx_ReceiveToIdle_DMA(&huart1,(uint8_t*)uart_buf_in,UART_SIZE);
__HAL_DMA_DISABLE_IT(&hdma_usart1_rx,DMA_IT_HT);
tmr_us_Start(&uart_rx_tmo,1500); //1.5ms
}
}
void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size){
if(huart == &huart1){
// process received data
// copy data to SPI outbuffer for next SPI poll
//memcpy(spi_buf_out,uart_buf_in,UART_SIZE); // spi_buf_out is now 1234 to test ...
// reset SPI DMA and FIFO
HAL_SPI_DMAStop(&hspi2);
__HAL_DMA_DISABLE(&hdma_usart1_rx);
__HAL_DMA_DISABLE(&hdma_usart1_tx);
HAL_SPI_TransmitReceive_DMA(&hspi2,spi_buf_out,spi_buf_in,SPI_SIZE);
}
}it finally works, your tip lead to the solution. Thank you . I summarize the solution for other people .
The HAL lib is not ideal for this setup, i would recommend other engineers to write their own code to acces the registers , getting this right took at least as much time then starting from 0.
the setup :
The Pi is SPI master , the STM SPI slave , each SPI package is forwarded to the UART, some external device answers. This answer is given back the next SPI packet initiated by the Pi.
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_DMA_Init();
MX_USART1_UART_Init();
MX_SPI2_Init();
HAL_SPI_TransmitReceive_DMA(&hspi2,spi_buf_out,spi_buf_in,SPI_SIZE);
}
// 1) SPI enable line will have positive flank once the data is transferred from PI to STM, this will be used as interrupt to
// copy the received SPI data into the uart output buffer and initiate a DMA transfer to the uart peripheral
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin){
if(GPIO_Pin == GPIO_PIN_12){
WritePin(PA10,1); //DE
memcpy(uart_buf_out,spi_buf_in,SPI_SIZE);
// reset uart to flush FIFO
HAL_UART_DeInit(&huart1);
__HAL_RCC_USART1_FORCE_RESET();
__HAL_RCC_USART1_RELEASE_RESET();
HAL_UART_Init(&huart1);
HAL_UART_Transmit_DMA(&huart1,(uint8_t *)(uart_buf_out+1),*(uint8_t *)(uart_buf_out));
}
}
// 2) after the DMA transfer at the UART peripheral, this callback will be called
// we use this to clear the RS485 DE line and start the DMA to start receiving data to the uart peripheral
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart){
if(huart == &huart1){
WritePin(PA10,0); //DE
HAL_UARTEx_ReceiveToIdle_DMA(&huart1,(uint8_t*)uart_buf_in,UART_SIZE);
__HAL_DMA_DISABLE_IT(&hdma_usart1_rx,DMA_IT_HT);
}
}
// 3) once data is received this callback is called
// we use this to copy the data in the uart inbuffer to the spi outbuffer, so the data will be available at the SPI bus at the next POLL
void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size){
if(huart == &huart1){
// process received data
// copy data to SPI outbuffer for next SPI poll
memcpy(spi_buf_out,uart_buf_in,UART_SIZE);
// reset spi to flush FIFO
HAL_SPI_DeInit(&hspi2);
__HAL_RCC_SPI2_FORCE_RESET();
__HAL_RCC_SPI2_RELEASE_RESET();
HAL_SPI_Init(&hspi2);
HAL_SPI_TransmitReceive_DMA(&hspi2,spi_buf_out,spi_buf_in,SPI_SIZE);
}
}
