NRF SDK 15.3 UART example is not working. - nRF52840 pca10056

[Casper Kronborg Pedersen]

Hi DevZone,

I am developing an application that needs to use UART communication with the nRF52840 pca10056 board.

I am using Segger Embedded Studio V4.16

I checked out the UART example found in the SDK files under \examples\peripheral\uart\pca10056\blank\ses\

I have setup my terminal program PuTTY with 115200 Baudrate, 8 Data bits, 1 Stop bit, No Parity and No Flow Control.

The example compiles fine, but  does not run. I get no echo in the terminal as expected.

When i build and debug, I immediately end up in the app_error_weak.c file at line 100 - NRF_BREAKPOINT_COND;

Are there any know issues with this example? I have searched the DevZone and did not find any related posts.

I hope you can point me in the right direction.

Br. Casper

[BinderT]

Hi,

Have you added this macro in. It's commented out by default.

line 66 in the example
#define ENABLE_LOOPBACK_TEST

Regards

[Casper Kronborg Pedersen]

Yes I also tried enabling loopback test, but the same error occurs.

[AndreasF]

Hi.

You compiled it out of the box?

It works fine for me:

The code I'm running:

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 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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 */
/** @file
 * @defgroup uart_example_main main.c
 * @{
 * @ingroup uart_example
 * @brief UART Example Application main file.
 *
 * This file contains the source code for a sample application using UART.
 *
 */

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include "app_uart.h"
#include "app_error.h"
#include "nrf_delay.h"
#include "nrf.h"
#include "bsp.h"
#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif


//#define ENABLE_LOOPBACK_TEST  /**< if defined, then this example will be a loopback test, which means that TX should be connected to RX to get data loopback. */

#define MAX_TEST_DATA_BYTES     (15U)                /**< max number of test bytes to be used for tx and rx. */
#define UART_TX_BUF_SIZE 256                         /**< UART TX buffer size. */
#define UART_RX_BUF_SIZE 256                         /**< UART RX buffer size. */

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);
    }
}


#ifdef ENABLE_LOOPBACK_TEST
/* Use flow control in loopback test. */
#define UART_HWFC APP_UART_FLOW_CONTROL_ENABLED

/** @brief Function for setting the @ref ERROR_PIN high, and then enter an infinite loop.
 */
static void show_error(void)
{

    bsp_board_leds_on();
    while (true)
    {
        // Do nothing.
    }
}


/** @brief Function for testing UART loop back.
 *  @details Transmitts one character at a time to check if the data received from the loopback is same as the transmitted data.
 *  @note  @ref TX_PIN_NUMBER must be connected to @ref RX_PIN_NUMBER)
 */
static void uart_loopback_test()
{
    uint8_t * tx_data = (uint8_t *)("\r\nLOOPBACK_TEST\r\n");
    uint8_t   rx_data;

    // Start sending one byte and see if you get the same
    for (uint32_t i = 0; i < MAX_TEST_DATA_BYTES; i++)
    {
        uint32_t err_code;
        while (app_uart_put(tx_data[i]) != NRF_SUCCESS);

        nrf_delay_ms(10);
        err_code = app_uart_get(&rx_data);

        if ((rx_data != tx_data[i]) || (err_code != NRF_SUCCESS))
        {
            show_error();
        }
    }
    return;
}
#else
/* When UART is used for communication with the host do not use flow control.*/
#define UART_HWFC APP_UART_FLOW_CONTROL_DISABLED
#endif


/**
 * @brief Function for main application entry.
 */
int main(void)
{
    uint32_t err_code;

    bsp_board_init(BSP_INIT_LEDS);

    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_115200
#endif
      };

    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);

#ifndef ENABLE_LOOPBACK_TEST
    printf("\r\nUART example started.\r\n");

    while (true)
    {
        uint8_t cr;
        while (app_uart_get(&cr) != NRF_SUCCESS);
        while (app_uart_put(cr) != NRF_SUCCESS);

        if (cr == 'q' || cr == 'Q')
        {
            printf(" \r\nExit!\r\n");

            while (true)
            {
                // Do nothing.
            }
        }
    }
#else

    // This part of the example is just for testing the loopback .
    while (true)
    {
        uart_loopback_test();
    }
#endif
}


/** @} */

Best regards,

Andreas

[Casper Kronborg Pedersen]

Hi,

Yes I compiled it straight out of the box. Just tried copying your code in and the error persists I am afraid.

Br. Casper

EDIT:
From what I can see when debugging, then the m_event_handler(&app_uart_event); is called in app_uart_fifo.c

This then goes directly into the app_error_fault_handler(NRF_FAULT_ID_SDK_ERROR, 0, (uint32_t)(&error_info)); in line 73 in app_error.c

The error code is 0x00000004

[AndreasF]

Hi.

Have you modified any source files used by different drivers in the SDK?

Could you try to compile the example from a clean SDK?

Best regards,

Andreas

[Casper Kronborg Pedersen]

Hi,

After the first fault I was worried about the same thing, so I unzipped a fresh copy of the SDK. But that did not solve the problem either.

Br. Casper

[Casper Kronborg Pedersen]

I have learned that error code 0x0000004 is representing NRF_ERROR_NO_MEM.

When I build my project the memory allocation looks as follows:

Is this the same for you?

Br. Casper

[Casper Kronborg Pedersen]

I have located the problem.

The UART on the development kit uses pins P0.05, P0.06, P0.07, P0.08.

I was using one if these pins (P0.08) for another device connected to the development kit.

I don't know why I got a NRF_ERROR_NO_MEM error code from this mistake, but at least now the example works as expected with echoing keyboard inputs on the terminal.

Thank you for helping me. It is much appreciated! :)

Br. Casper

[awneil]

Casper Kronborg Pedersen said:

I don't know why I got a NRF_ERROR_NO_MEM error code from this mistake

Possibly because you were getting framing errors on the UART:

https://devzone.nordicsemi.com/f/nordic-q-a/41480/multiperipheral-nus-crashes/161677#161677

[Casper Kronborg Pedersen]

Interesting read. This will probably save me in the near future. I did spend some time looking into the wrong things because of the NRF_ERROR_NO_MEM message.

Thank you for posting!

Br. Casper