APP_UART_COMMUNICATION_ERROR on handle

[diocorreia]

I'm having troubles parsing the received data stream form an UART device. If i just print whatever i received from the datastream, everything works just fine.

    if (p_event->evt_type == APP_UART_DATA_READY){
        app_uart_get(&rx);
        NRF_LOG_RAW_INFO("%c", rx);
        NRF_LOG_FLUSH();
    }

Howeve, if i try to store it in an external string and then print it , it returns APP_UART_COMMUNICATION_ERROR during reception.

    if (p_event->evt_type == APP_UART_DATA_READY){
        app_uart_get(&rx);
        if(rx == 0xD){
            buff[i] = (uint8_t)'\0';
            i = 0;
            NRF_LOG_RAW_INFO("%s", NRF_LOG_PUSH((char *)buff));
            NRF_LOG_FLUSH();
        }else{
            buff[i++] = rx;
        }
    }

[awneil]

What transport are you using for NRF_LOG ?

If it's UART, then NRF_LOG_FLUSH(); could take some time - and cause overrun in your data reception ... ?

diocorreia said:

it returns APP_UART_COMMUNICATION_ERROR

What is "it" ?

[diocorreia]

The project is based on the uart example (on peripheral) and uses RTT as NRF_LOG backend. The event handled by the function is from that type (APP_UART_COMMUNICATION_ERROR).

void uart_handle(app_uart_evt_t * p_event)
{
    uint8_t rx;
    if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
    {
        //APP_ERROR_HANDLER(p_event->data.error_communication);
        NRF_LOG_RAW_INFO("APP_UART_COMMUNICATION_ERROR\n");
        NRF_LOG_FLUSH();
    }
    else if (p_event->evt_type == APP_UART_FIFO_ERROR)
    {
        //APP_ERROR_HANDLER(p_event->data.error_code);        
        NRF_LOG_RAW_INFO("APP_UART_FIFO_ERROR\n");
        NRF_LOG_FLUSH();
    } else if (p_event->evt_type == APP_UART_DATA_READY){
        app_uart_get(&rx);
        NRF_LOG_RAW_INFO("%c", rx);
        NRF_LOG_FLUSH();
        nrf_delay_ms(1000);
    }
}

[Karl Ylvisaker]

Hi,

Could you tell me what the value of the event's error_communication is?
It contains the value of the ERRORSRC register, which will give us a clearer picture of what is going on.

As Awneil suggests it might very well be that your RX buffer overflows, such as if app_uart_get() is not called often enough.

Best regards,
Karl

[diocorreia]

It is an overrun problem (communication_error = 1), how could i deal with these problem? Increase the size of UART buffer will solve the problem?

[diocorreia]

Found a solution based on https://devzone.nordicsemi.com/f/nordic-q-a/38816/uart-event-handler-problems/150013#150013. Using a scheduler to handle the received characters solved my problem.