nRF52840 Dongle UART

[luca brandt]

Hello,

I use the Blinky example from the SDK. Now I would like to implement an UART on the nRF52840 Dongle. But the program always stops at either nrf_drv_uart_rx or nrf_drv_uart_tx. Can anyone help me with that?

Thanks in advance!

nrf_drv_uart_t upp_uart_inst = NRF_DRV_UART_INSTANCE(0);

void rm_uart_init()
{
    nrf_drv_uart_config_t vfg = NRF_DRV_UART_DEFAULT_CONFIG;
    cfg.baudrate    = UART_BAUDRATE_BAUDRATE_Baud115200;
    cfg.hwfc        = NRF_UART_HWFC_DISABLED;
    cfg.pselrxd     = 29;
    cfg.pseltxd     = 31;
    cfg.use_easy_dma= 0;
        
    nrf_drv_init(&app_drv_uart_init, &cfg, NULL);
}

void fkt()
{
    uint8_t tx_buffer[0] = 1;
    uint8_t rx_buffer[0] = 0;
    nrf_drv_uart_tx(&app_uart_inst, tx_buffer, 1);
    nrf_drv_uart_rx (&app_uart_inst, rx_buffer, 1);
}

[Edvin]

Ok, I just wanted to make 100% sure that you didn't think the pins were routed through the USB port (like it is on the DK). Then I am afraid you need to debug.

[lucaN]

Alright. I ordered one. Thank you for your help!

[lucaN]

I did some debugging now on the nRF52840 DK

uint8_t rx_buffer[1];
uint8_t tx_buffer[1];

nrf_drv_uart_t app_uart_inst = NRF_DRV_UART_INSTANCE(0);


uint32_t rm_uart_put(uint8_t c);
uint32_t rm_uart_get();

void rm_uart_init() 
{
    nrf_drv_uart_config_t cfg = NRF_DRV_UART_DEFAULT_CONFIG;

    cfg.baudrate              = UART_BAUDRATE_BAUDRATE_Baud115200;
    cfg.hwfc                  = NRF_UART_HWFC_DISABLED;
    cfg.pselrxd               = 26; // 29
    cfg.pseltxd               = 27; // 31
    cfg.use_easy_dma          = false;
 
    ret_code_t err_code;
    //err_code = nrfx_uart_init(&app_uart_inst, &cfg, NULL);
    err_code = nrf_drv_uart_init(&app_uart_inst, &cfg, 0); //Original
    APP_ERROR_CHECK(err_code);
}

void rm_uart_handle()
{
    uint32_t err_code;
    uint8_t send = 0;
    uint8_t recive = 1;

    err_code = rm_uart_put(send);

    recive = rm_uart_get();
}


uint32_t rm_uart_put(uint8_t c) 
{
    ret_code_t err_code;
    tx_buffer[0] = c;

    err_code = nrf_drv_uart_tx(&app_uart_inst, tx_buffer, 1);
    APP_ERROR_CHECK(err_code);
}

uint32_t rm_uart_get(void) 
{
    ret_code_t err_code;

    err_code = nrf_drv_uart_rx(&app_uart_inst, rx_buffer, 1);
    APP_ERROR_CHECK(err_code);

    return *rx_buffer;
}

That is the error I get from putting the breakpoint to error_info from the APP_ERROR_CHECK() after the nrf_drv_uart_init function:

void app_error_handler_bare(unsigned int error_code=0x00000011)

In the infocenter it says that the error 0x11 is: The length of one or more input arguments was invalid. The first input argument contains:

app_uart_inst = {inst_idx=x00, uarte={p_reg=0x40002000, drv_inst_idx=0x00}, uart={p_reg=40002000, drv_inst_idx=0x00}}

When I comment out that line 

    cfg.use_easy_dma          = false;

, I get a 0x08 error instead. I don't if that means anything because I still don't really know what to do with all that.

The UART Pins are not connected yet and advertising and BLE stuff is commented out.

[Edvin]

What SDK version do you use, by the way?

Is it possible to send the project, so that I can try to reproduce it?

I guess it comes from nrfx_uarte_init() -> 

nrfx_err_t nrfx_uarte_init(nrfx_uarte_t const *        p_instance,
                           nrfx_uarte_config_t const * p_config,
                           nrfx_uarte_event_handler_t  event_handler)
{
    NRFX_ASSERT(p_config);
    uarte_control_block_t * p_cb = &m_cb[p_instance->drv_inst_idx];
    nrfx_err_t err_code = NRFX_SUCCESS;

    if (p_cb->state != NRFX_DRV_STATE_UNINITIALIZED)
    {
        err_code = NRFX_ERROR_INVALID_STATE;
        NRFX_LOG_WARNING("Function: %s, error code: %s.",
                         __func__,
                         NRFX_LOG_ERROR_STRING_GET(err_code));
        return err_code;
    }

#if NRFX_CHECK(NRFX_PRS_ENABLED)
    static nrfx_irq_handler_t const irq_handlers[NRFX_UARTE_ENABLED_COUNT] = {
        #if NRFX_CHECK(NRFX_UARTE0_ENABLED)
        nrfx_uarte_0_irq_handler,
        #endif
        #if NRFX_CHECK(NRFX_UARTE1_ENABLED)
        nrfx_uarte_1_irq_handler,
        #endif
        #if NRFX_CHECK(NRFX_UARTE2_ENABLED)
        nrfx_uarte_2_irq_handler,
        #endif
        #if NRFX_CHECK(NRFX_UARTE3_ENABLED)
        nrfx_uarte_3_irq_handler,
        #endif
    };
    if (nrfx_prs_acquire(p_instance->p_reg,
            irq_handlers[p_instance->drv_inst_idx]) != NRFX_SUCCESS)
    {
        err_code = NRFX_ERROR_BUSY;
        NRFX_LOG_WARNING("Function: %s, error code: %s.",
                         __func__,
                         NRFX_LOG_ERROR_STRING_GET(err_code));
        return err_code;        // <-- This line
    }

Out of curiousity:

Do you (try to) use logging? Can you send me your sdk_config.h file? What is NRF_LOG_ENABLED and NRF_LOG_BACKEND_UART_ENABLED defined as, if they are present?

[Edvin]

I got your file from the message.

First of all, you have a few redefined definitions. LED_3, LED_4. You should make sure that defines like these only have one value. They are already defined in pca10056.h.

I can't compile the project, because there are a lot of undefined variables and functions. I guess you have some custom files outside the project folder, or that you changed some of the default files in the SDK. Try to compile your project in a new unzipped, unmodified SDK, and you will see.

However, your project uses the UART as a log backend, so you can't use it in the application. If you need the UART in addition to logging, you need to disable the log, or change to RTT backend.

I suggest that you change to the following in sdk_config.h:

#define NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 0
#define NRF_LOG_BACKEND_UART_ENABLED 0