Cannot transmit every characters through UART

Question

I am using stm32f0 MCU.

I would like to transmit every single byte received from the uart out of the uart. I am enabling an interrupt on every byte received from uar

Answer 1

Reenabling interrupts may be inefficient. With a couple of modifications it is possible to keep the interrupt active without needing to write the handler all over again. See the example below altered from the stm32cubemx generator.

/**
* @brief This function handles USART3 to USART6 global interrupts.
*/
void USART3_6_IRQHandler(void)
{
  InterruptGPS(&huart5);
}

void InterruptGPS(UART_HandleTypeDef *huart) {
    uint8_t rbyte;
    if (huart->Instance != USART5) {
        return;
    }
    /* UART in mode Receiver ---------------------------------------------------*/
    if((__HAL_UART_GET_IT(huart, UART_IT_RXNE) == RESET) || (__HAL_UART_GET_IT_SOURCE(huart, UART_IT_RXNE) == RESET)) {
        return;
    }
    rbyte = (uint8_t)(huart->Instance->RDR & (uint8_t)0xff);
    __HAL_UART_SEND_REQ(huart, UART_RXDATA_FLUSH_REQUEST);

    // do your stuff

}

static void init_gps() {
    __HAL_UART_ENABLE_IT(&huart5, UART_IT_RXNE);
}

Answer 2

You should make a tx array buffer as well, and use interrupt for writing as well (The first write if not enabled yet, should be sent immediately).

There should be examples of this for STM32 around.

Answer 3

You should probably switch the two lines: Transmit and Receive. The Transmit function waits for a timeout to send the character, in meantime the next received character is missed.