SDK 15.0 SPIM Example Issue on nRF52840

[aeozyalcin]

Hey all,

I am trying to run the "nrfx_spim" example on my nRF52840 USB Dongle (Makerdiary nRF52840 USB dongle), however it is not working. It looks like the code is never reaching the interrupt handler "spim_event_handler()". The example code is using SPI3 to run this example, and I confirmed that NRFX_SPIM3 is enabled in the sdk_config.h.

This is a dongle, so I don't have a way of seeing any of the NRF_LOG entries unfortunately.

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nrfx_spim_config_t spi_config = NRFX_SPIM_DEFAULT_CONFIG;

spi_config.frequency = NRF_SPIM_FREQ_1M;

spi_config.ss_pin = NRFX_SPIM_SS_PIN;

spi_config.miso_pin = NRFX_SPIM_MISO_PIN;

spi_config.mosi_pin = NRFX_SPIM_MOSI_PIN;

spi_config.sck_pin = NRFX_SPIM_SCK_PIN;

spi_config.dcx_pin = NRFX_SPIM_DCX_PIN;

spi_config.use_hw_ss = true;

spi_config.ss_active_high = true;

spi_config.mode = NRF_SPIM_MODE_1;

APP_ERROR_CHECK(nrfx_spim_init(&spi, &spi_config, spim_event_handler, NULL));

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nrfx_spim_config_t spi_config = NRFX_SPIM_DEFAULT_CONFIG;
spi_config.frequency      = NRF_SPIM_FREQ_1M;
spi_config.ss_pin         = NRFX_SPIM_SS_PIN;
spi_config.miso_pin       = NRFX_SPIM_MISO_PIN;
spi_config.mosi_pin       = NRFX_SPIM_MOSI_PIN;
spi_config.sck_pin        = NRFX_SPIM_SCK_PIN;
spi_config.dcx_pin        = NRFX_SPIM_DCX_PIN;
spi_config.use_hw_ss      = true;
spi_config.ss_active_high = true;
spi_config.mode           = NRF_SPIM_MODE_1; 

APP_ERROR_CHECK(nrfx_spim_init(&spi, &spi_config, spim_event_handler, NULL));

Here is the interrupt handler:

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void spim_event_handler(nrfx_spim_evt_t const * p_event,

void * p_context)

{

bsp_board_led_invert(BSP_BOARD_LED_1);

spi_xfer_done = true;

NRF_LOG_INFO("Transfer completed.");

if (m_rx_buf[0] != 0)

{

NRF_LOG_INFO(" Received:");

NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));

}

}

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void spim_event_handler(nrfx_spim_evt_t const * p_event,
                       void *                  p_context)
{
	bsp_board_led_invert(BSP_BOARD_LED_1);

    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    if (m_rx_buf[0] != 0)
    {
        NRF_LOG_INFO(" Received:");
        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
    }
}

Here is the main loop that is supposed to send out a packet every 200 ms:

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while (1)

{

// Reset rx buffer and transfer done flag

memset(m_rx_buf, 0, m_length);

spi_xfer_done = false;

APP_ERROR_CHECK(nrfx_spim_xfer(&spi, &xfer_desc, 0));

while (!spi_xfer_done)

{

__WFE();

}

NRF_LOG_FLUSH();

bsp_board_led_invert(BSP_BOARD_LED_1);

nrf_delay_ms(200);

}

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

	APP_ERROR_CHECK(nrfx_spim_xfer(&spi, &xfer_desc, 0));


    while (!spi_xfer_done)
    {
        __WFE();
    }

    NRF_LOG_FLUSH();

    bsp_board_led_invert(BSP_BOARD_LED_1);
    nrf_delay_ms(200);
}

I checked the SPI lines on my oscilloscope, and I see that the SS pin goes high (I have it set to active high polarity), the SPI clock runs, and I can see data being pushed out on the MOSI pin. However, after the transaction ends, the SS pin does not go back low, and the interrupt handler does not trigger. I reckon the issue is with the end of the transaction, but can't figure out what's wrong. I hope someone can help, thanks!