HAL_UART_RxCpltCallback not called in DMA

[_alaBaster]

Hi Everybody, 

• USART interrupt enabled
• DMA interrupt enabled
• USART2_RX circular 
• USART2_TX normal

Simplifying code to the essential part here, code is receiving the bytes in the circular buffer but it does not jump to HAL_UART_RxCpltCallback. Could someone please give some hints, what am I missing here?

#define UART_BUFFER_SIZE 4
__IO uint8_t uartBuffer[UART_BUFFER_SIZE];

void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_DMA_Init(void);
static void MX_USART2_UART_Init(void);

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
  HAL_Delay(1000);
  HAL_UARTEx_ReceiveToIdle_DMA(&huart2,(uint8_t *) &uartBuffer, UART_BUFFER_SIZE);
}

int main(void)

{

  HAL_Init();

  SystemClock_Config();

  MX_GPIO_Init();

  MX_DMA_Init();

  MX_USART2_UART_Init();

  memset((uint8_t *) &uartBuffer, 0, sizeof(uartBuffer)); // Clear buffer

  HAL_UARTEx_ReceiveToIdle_DMA(&huart2,(uint8_t *) &uartBuffer, UART_BUFFER_SIZE);

  while (1)

  {

    HAL_Delay(1000);

  }

}

[TDK · Accepted solution]

The HAL_UARTEx_ReceiveToIdle_DMA function will call the HAL_UARTEx_RxEventCallback callback, not HAL_UART_RxCpltCallback.

See example (non-funcitonal) weak implementation here:

/**
  * @brief  Reception Event Callback (Rx event notification called after use of advanced reception service).
  * @PAram  huart UART handle
  * @PAram  Size  Number of data available in application reception buffer (indicates a position in
  *               reception buffer until which, data are available)
  * @retval None
  */
__weak void HAL_UARTEx_RxEventCallback(UART_HandleTypeDef *huart, uint16_t Size)
{
  /* Prevent unused argument(s) compilation warning */
  UNUSED(huart);
  UNUSED(Size);

  /* NOTE : This function should not be modified, when the callback is needed,
            the HAL_UARTEx_RxEventCallback can be implemented in the user file.
   */
}

[_alaBaster]

okay thanks.

When I instead use the HAL_UART_Receive_DMA, no callback is triggered at the end, isnt it?

[TDK]

When you use HAL_UART_Receive_DMA, then HAL_UART_RxCpltCallback will be called when the reception is complete. It will not be called until you receive all and exactly the number of characters you ask for.