STM32L562 UART Data Rx packet loss

[414D414E]

Hi,

I am using USART4 in STM32L562E-DK eval board. with given configuration.

In which I am able to transmit the data correctly on TX based on which UART slave device is sending back the 4 bytes ACK and 16 bytes RESPONSE.

Using following code

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
  if (huart->Instance == UART4) // check correct UART
  {
    // Store received byte
    //UART_Print("bytercv\r\n");
    if (rxIndex < RX_BUFFER_SIZE_4)
    {
      rxBuffer4[rxIndex++] = rxData;
    }

    // Check if done
    if (rxIndex >= rxTargetLen)
    {
      rxComplete = 1; // Mark reception complete
    }
    else
    {
      // Keep receiving next byte
      HAL_UART_Receive_IT(&huart4, &rxData, 1);
    }
  }
}

I am able to receive the ACK but after some time when I read the RESPONSE there is not data available.

If I am reading only 4bytes of data what happens to remaining data is it loss?

Or I have to use FIFO based UART implementation.

Regards,

Aman 

---

Edited to apply source code formatting - please see How to insert source code for future reference.

[TDK]

> If I am reading only 4bytes of data what happens to remaining data is it loss?

If you don't read out a byte before a new byte comes in, an overrun occurs and the new data will be lost. The peripheral will need to have the OVR flag cleared before it will receive new data.