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nRF52840 SPIM cannot get input data, while oscilloscope signals are right.

Hi everybody! My application is based on SDK 17.02. I try to communicate with an spi device using spim driver and the code is basically based on the nrfx-spim example.

After some effort, now I managed to get the right signals on a oscilloscope. But I just cannot get the input in my application. Any suggestion is largely appreciated

Below are my code.

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#include "nrfx_spim.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "SEGGER_RTT.h"

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define NRFX_SPIM_SCK_PIN  NRF_GPIO_PIN_MAP(1,9)
#define NRFX_SPIM_MOSI_PIN NRF_GPIO_PIN_MAP(0,6)
#define NRFX_SPIM_MISO_PIN NRF_GPIO_PIN_MAP(0,5)
#define NRFX_SPIM_SS_PIN   NRF_GPIO_PIN_MAP(0,8)

//#define NRFX_SPIM_DCX_PIN  30

#define SPI_INSTANCE  3                                           /**< SPI instance index. */
static const nrfx_spim_t spi = NRFX_SPIM_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */

static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */
#define BUF_LEN 128
static uint8_t       m_tx_buf[BUF_LEN] ;           /**< TX buffer. */
static uint8_t       m_rx_buf[BUF_LEN] ;  /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

void spim_event_handler(nrfx_spim_evt_t const * p_event,
                       void *                  p_context)
{
    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    NRF_LOG_INFO("RX buf:");
        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
	
//    if (m_rx_buf[0] != 0)
//    {
//        NRF_LOG_INFO(" Received:");
//        NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
//    }
}

int main(void)
{
    bsp_board_init(BSP_INIT_LEDS);
    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();

	m_tx_buf[0] = 0x93;
	m_tx_buf[1] = 0xff;
    nrfx_spim_xfer_desc_t xfer_desc = NRFX_SPIM_XFER_TRX(m_tx_buf, 2, m_rx_buf, 2);
	
    nrfx_spim_config_t spi_config = NRFX_SPIM_DEFAULT_CONFIG;
    spi_config.frequency      = NRF_SPIM_FREQ_500K;
    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.mode 		  = NRF_SPIM_MODE_3;

	
    spi_config.use_hw_ss      = false;
    spi_config.ss_active_high = false;
//	  spi_config.rx_delay     = 0x02;                
//    spi_config.ss_duration  = 0x02;
    APP_ERROR_CHECK(nrfx_spim_init(&spi, &spi_config, spim_event_handler, NULL));
		

    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_0);
        nrf_delay_ms(200);
    }
}

Parents
  • Thanks for reply. I have just solved the problem. just look at 

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

    When the fisrt byte received by the spim driver is 0x00, strlen((const char *)m_rx_buf)) will return 0. Thus the callback will print nothing for ever. So I tried to print m_rx_buf[1] and finally I got the device ID. Maybe the sdk examples should fix this emmm...bug?

    Best regards

Reply
  • Thanks for reply. I have just solved the problem. just look at 

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

    When the fisrt byte received by the spim driver is 0x00, strlen((const char *)m_rx_buf)) will return 0. Thus the callback will print nothing for ever. So I tried to print m_rx_buf[1] and finally I got the device ID. Maybe the sdk examples should fix this emmm...bug?

    Best regards

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