SPI slave example from sdk 15.2 not working

Question

Hello,

I am trying to execute the SPI slave example from sdk15.2 on my NRF52832 Dev board (PCA10040 1.2.1).

I am using stm32f0 dev board as the master and transmitting the value 0x20 in a 100ms raster. I have tried using SPI clocks from 125k to 1M and I am facing the same error.

The RX buffer is getting filled with 0xFF no matter what data i transmit. I have posted my code below

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#include "sdk_config.h"
#include "nrf_drv_spis.h"
#include "nrf_gpio.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_delay.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define SPIS_INSTANCE 1 /**< SPIS instance index. */
static const nrf_drv_spis_t spis = NRF_DRV_SPIS_INSTANCE(SPIS_INSTANCE);/**< SPIS instance. */

#define TEST_STRING "hyuvgh"
 uint8_t       m_tx_buf[] = TEST_STRING; /**< TX buffer. */
uint8_t randdom[29];
 uint8_t       m_rx_buf[3] ={1,2,3};    /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

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;
 
        NRF_LOG_INFO(" Transfer completed. Received: %d %d %d",(int32_t)m_rx_buf[0],(uint32_t)m_rx_buf[1],(uint32_t)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;
    spis_config.def = 0x11;
    APP_ERROR_CHECK(nrf_drv_spis_init(&spis, &spis_config, NULL));

    while (1)
    {
        memset(m_rx_buf, 0, 3);
        spis_xfer_done = false;

        APP_ERROR_CHECK(nrf_drv_spis_buffers_set(&spis, m_tx_buf, 1, m_rx_buf, 1));

//        while (!spis_xfer_done)
//        {
////            __WFE();
//        }
//        nrf_delay_ms(1000);
        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
    }
}

I have tried using it on non-blocking mode by not referencing the SPIS_Handler but then the MCU wasn't even going past the first SPIS command.

I have also tried changing TX and RX size and still no results. Please tell me if I am missing out something here.

Here is a snippet from logic analyser

here are my pin configurations

Thank you.

Jørgen Holmefjord · Accepted Answer

Hi, 
 The SPIS peripheral of nRF52832 support a maximum frequency of 8 Mbps. 
 Best regards, Jørgen

SPI slave example from sdk 15.2 not working

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