Libuarte+app template ERROR 0 [NRF_SUCCESS]

[Muqarrab]

Hi,
I have added libuarte example in-app template and sent data from Arduino to nRF52840 successfully. But after receiving some data and I am getting the following error. Any solution please?
Thanks!

[Jared]

Hi,

Have you remembered to free the RX buffer in the uart event handler? Could you show me how the handler has been implemented? 

regards

Jared 

[Muqarrab]

Thanks for the reply. Here is the function

void uart_event_handler(void * context, nrf_libuarte_async_evt_t * p_evt)
{
    nrf_libuarte_async_t * p_libuarte = (nrf_libuarte_async_t *)context;
    ret_code_t ret;

    switch (p_evt->type)
    {
        case NRF_LIBUARTE_ASYNC_EVT_ERROR:
            break;
        case NRF_LIBUARTE_ASYNC_EVT_RX_DATA:

            if((unsigned char)*(p_evt->data.rxtx.p_data)!=0)
            {
                  received_data[count_data]=(unsigned char)*(p_evt->data.rxtx.p_data);
                  count_data=count_data+1;
                  if((unsigned char)*(p_evt->data.rxtx.p_data)==35)
                      data_completed=true;
            }

            m_loopback_phase = true;
            break;
        case NRF_LIBUARTE_ASYNC_EVT_TX_DONE:
            if (m_loopback_phase)
            {
                nrf_libuarte_async_rx_free(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);
                if (!nrf_queue_is_empty(&m_buf_queue))
                {
                    buffer_t buf;
                    ret = nrf_queue_pop(&m_buf_queue, &buf);
                    APP_ERROR_CHECK(ret);
                    UNUSED_RETURN_VALUE(nrf_libuarte_async_tx(p_libuarte, buf.p_data, buf.length));
                }
            }

            printf("Tx Called\n");

            break;
        default:
            break;
    }
}


//UART

[Muqarrab]

Does any suggestions please?

[Elfving]

Hey Muqarrab!

I guess it is understandable that you dont want the TX event, as the echo part of the example isn't what you are after. But the buffer is being freed in the case for TX, so you would have to move a couple lines around. As I mentioned earlier, the buffer not being freed in the right spots is what is causing your error.

I would suggest that you try to remove the echo-like TX lines, save the data from the buffer in an array or whatever you want, and then free the buffer. All in the RX event.

Regards,

Elfving

[Muqarrab]

Thanks, Elfving
I am trying to do the same, saving data from the buffer in an array and then freeing the buffer. All in the RX event. Here is my event handler. is this the right way to free RX buffer?

void uart_event_handler(void *context, nrf_libuarte_async_evt_t *p_evt) {
  nrf_libuarte_async_t *p_libuarte = (nrf_libuarte_async_t *)context;
  ret_code_t ret;

  switch (p_evt->type) {
  case NRF_LIBUARTE_ASYNC_EVT_ERROR:
    break;
  case NRF_LIBUARTE_ASYNC_EVT_RX_DATA:

    if (count_data < 50) {
      if ((unsigned char)*(p_evt->data.rxtx.p_data) != 0) 
      {

     // Receive complete
        received_data[count_data] = (unsigned char)*(p_evt->data.rxtx.p_data);
        count_data = count_data + 1;
        if ((unsigned char)*(p_evt->data.rxtx.p_data) == 35)
        {
          check_data();
          data_completed = true;
        }
      }
    } else {
      count_data = 0;
    }

    buffer_t buf;
      if (!nrf_queue_is_empty(&m_buf_queue)) {
        buffer_t buf;
        ret = nrf_queue_pop(&m_buf_queue, &buf);
        APP_ERROR_CHECK(ret);
        UNUSED_RETURN_VALUE(nrf_libuarte_async_tx(p_libuarte, buf.p_data, buf.length));
      }



    // ret = nrf_libuarte_async_tx(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);
    // if (ret == NRF_ERROR_BUSY) {
    //  buffer_t buf = {
    //      .p_data = p_evt->data.rxtx.p_data,
    //      .length = p_evt->data.rxtx.length,
    //  };

    //  ret = nrf_queue_push(&m_buf_queue, &buf);
    //  APP_ERROR_CHECK(ret);
    //} else {
    //  APP_ERROR_CHECK(ret);
    //}
    //  printf("Counter : %d",count_data);



   // nrf_libuarte_async_rx_free(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);
    m_loopback_phase = true;
    break;
  case NRF_LIBUARTE_ASYNC_EVT_TX_DONE:
    if (m_loopback_phase) {
      nrf_libuarte_async_rx_free(p_libuarte, p_evt->data.rxtx.p_data, p_evt->data.rxtx.length);

      if (!nrf_queue_is_empty(&m_buf_queue)) {
        buffer_t buf;
        ret = nrf_queue_pop(&m_buf_queue, &buf);
        APP_ERROR_CHECK(ret);
        UNUSED_RETURN_VALUE(nrf_libuarte_async_tx(p_libuarte, buf.p_data, buf.length));
      }
    }

   // printf("Tx Called\n");

    break;
  default:
    break;
  }
}

//UART

[Muqarrab]

Reply, please.

[Elfving]

Hello Muqarrab, sorry about the delay.

That looks promising. I think you can remove the loopback phase variable as well, and move the nrf_libuarte_async_rx_free call to the end of the RX event.

Regards,

Elfving