Struggling to get SPI working

[nrbrook]

I've adapted the SPI example to read a value from an Analog Devices ADXL350 accelerometer as follows:

int main(void)
{
    bsp_board_leds_init();

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();
    
    NRF_LOG_INFO("SPI example.");

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    spi_config.ss_pin   = SPI_SS_PIN;
    spi_config.miso_pin = SPI_MISO_PIN;
    spi_config.mosi_pin = SPI_MOSI_PIN;
    spi_config.sck_pin  = SPI_SCK_PIN;
    spi_config.bit_order = NRF_DRV_SPI_BIT_ORDER_MSB_FIRST;
    spi_config.mode = NRF_DRV_SPI_MODE_0;
    spi_config.frequency = NRF_DRV_SPI_FREQ_125K;
    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

    while (1)
    {
        // Reset rx buffer and transfer done flag
        memset(m_rx_buf, 0, m_length);
        spi_xfer_done = false;
        
        uint8_t tx = 0x2c | 0x80;
        uint8_t rx = 0;

        APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, &tx, 1, &rx, 1));

        while (!spi_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_INFO("Read %X", rx);

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
        nrf_delay_ms(200);
    }
}

But when connected to the accelerometer this hangs waiting for the transfer to finish. I'm not sure what I'm doing wrong here, do you have any advice?

I'm using nRF52DK and as per the example code, I'm using pins 3,4,28,29 for the SPI connections

[Jørgen Holmefjord]

Is it hanging on line 31 of your attached code? How does your spi_event_handler look? Are you setting spi_xfer_done in the handler? Have you tried debugging the application, to see if the event handler is ever called? Have you checked the SPI bus using a logic analyzer, to see if any data is transmitted?

[nrbrook]

In the end I got it working with a different accelerometer. I might try again with this accelerometer in the future and will update the question again if I do. Thanks

[natersoz]

If you are using the ST accelerometers, realize that they come up with I2C enabled on the same pins as SPI. You have to set the configuration (I don't recall the details) but it is in the data sheets.