Unable to read chunk of data from Peripheral\SPIS Example

[usr123]

Hi,

       I'm trying to implement a  SPI Communication between Arduino UNO and PCA10056 DK.  PCA10056 DK run as a SPI slave.. Arduino uno run as a SPI Master. 

      The problem is SPI Master keep sending a chunk of data (size - 25 bytes ) by each second..  But I'm unable to receive 25 bytes  from PCA 10056 board.

       Sometimes I receive 10 bytes or 12 bytes... not sure why it happening

       Is it any Mode issue or Clock div?

[Turbo J]

usr123 said:

 Is it any Mode issue or Clock div?

Impossible to say without looking at code or the plot on a DSO (digital storage oscilloscope, 4 channels recommended for SPI).

[usr123]

#define TEST_STRING "Nordic"
static uint8_t       m_tx_buf[25];           /**< TX buffer. */
static uint8_t       m_rx_buf[25];    /**< RX buffer. */
static const uint8_t m_length =25;        /**< Transfer length. */
//static char     m_buf={0};

static volatile bool spis_xfer_done; /**< Flag used to indicate that SPIS instance completed the transfer. */

/**
 * @brief SPIS user event handler.
 *
 * @param event
 */
void spis_event_handler(nrf_drv_spis_event_t event)
{
    if (event.evt_type == NRF_DRV_SPIS_XFER_DONE)
    {
	spis_xfer_done = true;
		//if(event.rx_amount>2)
		//{
            NRF_LOG_INFO(" Transfer completed. Received: %d   %X",event.rx_amount);//,m_rx_buf[0]);//event.rx_amount,m_rx_buf[0],m_rx_buf[1],m_rx_buf[2]);
		//}
    }
}

int main(void)
{
    // Enable the constant latency sub power mode to minimize the time it takes
    // for the SPIS peripheral to become active after the CSN line is asserted
    // (when the CPU is in sleep mode).
    NRF_POWER->TASKS_CONSTLAT = 1;

    bsp_board_init(BSP_INIT_LEDS);

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

    NRF_LOG_INFO("SPIS example");

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

    while (1)
    {
        memset(m_rx_buf, 0, m_length);
        spis_xfer_done = false;

        APP_ERROR_CHECK(nrf_drv_spis_buffers_set(&spis, m_tx_buf, m_length, m_rx_buf, m_length));
        while (!spis_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
    }
}

 The amount of received byte ...I'm printing it on console.

[Edvin]

spis_config has a parameter:

spis_config.mode = NRF_SPIS_MODE_0, which is set by NRF_DRV_SPIS_DEFAULT_CONFIG;

Try all the modes with your SPIM:

NRF_SPIS_MODE_0
NRF_SPIS_MODE_1
NRF_SPIS_MODE_2
NRF_SPIS_MODE_3

And see if you receive all the data with any of these. Perhaps the master is using another mode than NRF_SPIS_MODE_0.

BR,
Edvin