app_uart_get more than 1 byte

[Caner Celiktas]

Hi,

I'm using app_uart for communication between different mcu. I can send more than 1 byte like "0x3917015623"  through  changing tx_buffer[0] to tx_buffer[5]. Unfortunately i couldn't recieve the slave devicess message "0x2917013607". I can only get the first byte "0x07". My configuration are the same as uart example. How can i recieve all the message ?. I tried to use serial library but i couldn't initialize. (It gave ERROR 6 NRF_ERROR_NOT_SUPPORTED).

Slave device is sending me a message every second. And i'm calling app_uart_get function every 500 miliseconds.

Here is my uart init;

void uart_error_handle(app_uart_evt_t * p_event)
{
    if (p_event->evt_type == APP_UART_COMMUNICATION_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_communication);
    }
    else if (p_event->evt_type == APP_UART_FIFO_ERROR)
    {
        APP_ERROR_HANDLER(p_event->data.error_code);
    }    
}

void uart_init(void)
{
    uint32_t err_code;
    const app_uart_comm_params_t comm_params =
        {
            RX_PIN_NUMBER,
            TX_PIN_NUMBER,
            RTS_PIN_NUMBER,
            CTS_PIN_NUMBER,
            UART_HWFC,
            false,
  #if defined (UART_PRESENT)
            NRF_UART_BAUDRATE_115200
  #else
            NRF_UARTE_BAUDRATE_9600
  #endif
        };
//    const app_uart_buffers_t m_buffers =
//      {
//        &rx_buffer_s,
//        sizeof(rx_buffer_s),
//        &tx_buffer_s,
//        sizeof(tx_buffer_s)
//      }
      APP_UART_FIFO_INIT(&comm_params,
                           UART_RX_BUF_SIZE,
                           UART_TX_BUF_SIZE,
                           uart_error_handle,
                           APP_IRQ_PRIORITY_LOWEST,
                           err_code);

      APP_ERROR_CHECK(err_code);
//      err_code = app_uart_init(&comm_params, &m_buffers, uart_error_handle, APP_IRQ_PRIORITY_LOW);
//      APP_ERROR_CHECK(err_code);
  
}

Regards,

[bjorn-spockeli]

What are you passing as the timeout_ms value when you call nrf_serial_read?

/**
 * @brief Function for reading from a serial port.
 *
 * @param p_serial   Serial port instance.
 * @param p_data     Receive buffer pointer.
 * @param size       Receive buffer size.
 * @param p_read     Amount of data actually read from the serial port.
 *                   NULL pointer can be passed.
 * @param timeout_ms Operation timeout, in milliseconds. Pass 0 to operate in
 *                   non blocking mode.
 *
 * @return Standard error code.
 * */
ret_code_t nrf_serial_read(nrf_serial_t const * p_serial,
                           void * p_data,
                           size_t size,
                           size_t * p_read,
                           uint32_t timeout_ms);

[Caner Celiktas]

uint32_t err_code;

err_code = nrf_serial_read(&serial_uart, &rx_message, sizeof(rx_message), NULL, 10);
NRF_LOG_INFO("Recieved error : %d \n",err_code);
if(err_code == 13)
{
  ret = nrf_serial_uninit(&serial_uart);
  APP_ERROR_CHECK(ret);
  nrf_delay_ms(10);
  ret = nrf_serial_init(&serial_uart, &m_uart0_drv_config, &serial_config);
  APP_ERROR_CHECK(ret);

}
(void)nrf_serial_flush(&serial_uart, 0);
if(rx_message[3]>0)
    NRF_LOG_INFO("Recieved data : %d \n", rx_message[3]);
    
rx_message[3] = rx_data;
our_rx_characteristic_update(&m_our_service, &rx_data);
err_code = 0;

I call this function each second. When i connected the Board via BLE, frequency of errors is increasing.

[bjorn-spockeli]

Hi Mehmet, 

the SoftDevice( i.e. BLE protocol stack) has the highest priority so whenever there is a BLE event, then the SoftDevice will preempt any application code, see Interrupt priority levels in the SoftDevice Specification. 

So the fact that you see timeouts when there is BLE activity is to be expected as the SoftDevice will get priority over the application UART code. It is possible to schedule application code around the BLE events using the Timeslot API, see Concurrent multiprotocol implementation using the Radio Timeslot API

Best regards

Bjørn

[Caner Celiktas]

Is there any example of it ? Would you please explain ".It is possible to schedule application code around the BLE events using the Timeslot API "?. Did you mean scheduler ?

[bjorn-spockeli]

We have a tutorial on the Timeslot API. Its based on SDK v11, but the Timeslot API has not changed very much since then so it should still be relevant, see https://devzone.nordicsemi.com/nordic/short-range-guides/b/software-development-kit/posts/setting-up-the-timeslot-api. 

The Timeslot API allows the application to request a timeslot where you are guaranteed that there will be no interrupts from the SoftDevice. YOu can perform the UART transaction in the Timeslot to avoid the timeout issues.