1 ACCEPTED SOLUTION
Accepted Solutions
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);
}
}
