UART doesn't work when enable SPIS

[LostEcho]

Hi guys,

I am using SPIS to receive data from a camera and use UART to put this data back into the terminal. However, I noticed that my UART wouldn't print anything as long as I enabled the SPIS. I do use retargeting to make sure app_uart_put is working as expected. BTW, uart works fine when I disable the SPIS. 

void uart_spis_init() {
    uint32_t err_code;

    nrf_drv_spis_config_t spis_config = NRF_DRV_SPIS_DEFAULT_CONFIG;
    spis_config.csn_pin               = APP_SPIS_CS_PIN;
    spis_config.miso_pin              = APP_SPIS_MISO_PIN;
    spis_config.mosi_pin              = APP_SPIS_MOSI_PIN;
    spis_config.sck_pin               = APP_SPIS_SCK_PIN;
    spis_config.irq_priority          = APP_SPIS_IRQ_PRIORITY;

    APP_ERROR_CHECK(nrf_drv_spis_init(&spis, &spis_config, spis_event_handler));

    const app_uart_comm_params_t comm_params =
      {
          RX_PIN_NUMBER,
          TX_PIN_NUMBER,
          RTS_PIN_NUMBER,
          CTS_PIN_NUMBER,
          UART_HWFC,
          false,
          NRF_UART_BAUDRATE_115200
      };

    APP_UART_FIFO_INIT(&comm_params,
                         UART_RX_BUF_SIZE,
                         UART_TX_BUF_SIZE,
                         uart_error_handle,
                         APP_IRQ_PRIORITY_HIGHEST,
                         err_code);

    APP_ERROR_CHECK(err_code);
}

void spis_event_handler(nrf_drv_spis_event_t event)
{
    if (event.evt_type == NRF_DRV_SPIS_XFER_DONE)
    {

        spis_xfer_done = true;
        app_uart_put("K");
    }
}

int main(void)
{   
    ret_code_t err_code;
    bsp_board_init(BSP_INIT_LEDS);   
    err_code = nrf_drv_gpiote_init(); // Initialize the GPIOTE
    APP_ERROR_CHECK(err_code);
    uart_spis_init();
    while (true)
    {
        spis_xfer_done = false;
        app_uart_put('A');  #uart output testing
        memset(m_rx_buf, 0, m_rx_length);
        APP_ERROR_CHECK(nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_tx_length, m_rx_buf, m_rx_length));
        while (!spis_xfer_done);

        
    }
}

[Jørgen Holmefjord]

Hi,

Are you not seeing any output from the UART, including the first 'A'?

Are you using the default pins for the defines used for both UART and SPIS?

Is the application working as expected apart from this, or does it hang/go into a reset loop? Have you debugged the application to look for error codes from the SPIS and UART init functions?

Best regards,
Jørgen

[LostEcho]

Hi Jorgen,

Thanks for your reply. I have solved this problem. Turns out that I assigned the same pin for RX and SCK, and retarget.c cannot recognize anything if I do this. Now everything is working. 

Best,

DY