SPIS data corrupted (using example firmwares for SPIS and NRFx_SPIM)

[ryerye120]

I'm currently trying to set up a simple demo using 2 dev kits running the SPIS and NRFx_SPIM examples but the SPIS seems to always send corrupted data over the MISO line. I've attached zips of my spis and nrfx_spim firmwares below.  The only changes remaining are a slightly updated test string and the disabling of DCX.

0552.nrfx_spim.zip

6523.spis_chars.zip

Rather than sending the expected "nordic123456", the slave device sends out ".ordic123456" where the period is NRF_LOG_HEXDUMP_INFO's attempt at interpreting 'FF' or 'CE'. Am I not supposed to use the spis example firmware with the nrfx_spim? Surely someone must have run into this problem before.

Also at this point I've tried out multiple physical dev kits to make sure there wasn't some hardware/chip specific/lemon issue. Furthermore, I've tried adding delays between the toggling of CS and data being shifted out over MOSI but for whatever reason, no matter how long of a delay I add, the delay doesn't change anything. 

Any help would be greatly appreciated. I've been stuck on this for weeks and can't seem to move past it.

Kindest regards,

Ryan

[Jared]

Hi,

Your code looks ok.

But the documentation states that the SPI slave example should be used with the SPI Master example.

regards

Jared

[ryerye120]

Jared!! It's wonderful to hear from you again and thank you for the quick response.

Does that mean the following two examples can't be used together?

• sdk17.1.0/examples/peripherals/nrfx_spim
• sdk17.1.0/examples/peripherals/spis

Is there some workaround? Or am I misunderstanding something about what the spis peripheral can handle? 

Kindest regards,

Ryan

[Jared]

Hi Ryan,

Well,the nrfx_spim example wasn't made to be used together with the SPIS example, but I'm sure that it should work with some modifications. I did some quick tests and was able to get the SPIS to send the correct data by adjusting the buffers size on the SPIS end so that it was equal to the buffers on the master side, disable the DCX, and decreasing the frequency to 250 kHz. I'm not sure exactly why decreasing the frequency helped but it seems like the SPIS isn't able to answer in time with the nrfx_spim running at 1 MHz. 

1MHz:

250K Hz:

I suggest that you try the SPI master example and compare the output on the signal pins with the nrfx_spim example and see if you find any difference. 

best regards

Jared

#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_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 "Nordic123456789012345678901234567890"
static uint8_t       m_tx_buf[] = TEST_STRING;              /**< TX buffer. */
static uint8_t       m_rx_buf[sizeof(TEST_STRING)+1];    /**< 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: %s",(uint32_t)m_rx_buf);
    }
}

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);
    }
}

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

#define NRFX_SPIM_SCK_PIN  3
#define NRFX_SPIM_MOSI_PIN 4
#define NRFX_SPIM_MISO_PIN 28
#define NRFX_SPIM_SS_PIN   29
#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 TEST_STRING "Nordic123456789012345678901234567890"
static uint8_t       m_tx_buf[] = TEST_STRING;           /**< TX buffer. */
static uint8_t       m_rx_buf[sizeof(TEST_STRING) + 1];  /**< 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.");
    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();

    nrfx_spim_xfer_desc_t xfer_desc = NRFX_SPIM_XFER_TRX(m_tx_buf, m_length, m_rx_buf, m_length);

    nrfx_spim_config_t spi_config = NRFX_SPIM_DEFAULT_CONFIG;
    spi_config.frequency      = NRF_SPIM_FREQ_250K;
    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 = false;
    APP_ERROR_CHECK(nrfx_spim_init(&spi, &spi_config, spim_event_handler, NULL));

    NRF_LOG_INFO("NRFX SPIM example started.");

    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_dcx(&spi, &xfer_desc, 0, 15));
        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);
    }
}

[Jared]

Hi again,

I saw that my colleague gave you a good suggestion here. Could you try to follow up his suggestion and see if that fix your issue?

regards

Jared 

[ryerye120]

Jared you caught me - I was worried that thread had died so I posted again. 

Regardless, your suggestion indeed worked! Furthermore, the other thread also bore successful fruit. For anyone else who may run into the same mistake, I ran into: the final solution involves increasing the delay between CS going low and data being shifted over MOSI/MISO. The best way to ensure this seems to be toggling CS in software on your own.

Here is my main code as an example:

/**
 * Copyright (c) 2017 - 2021, Nordic Semiconductor ASA
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form, except as embedded into a Nordic
 *    Semiconductor ASA integrated circuit in a product or a software update for
 *    such product, must reproduce the above copyright notice, this list of
 *    conditions and the following disclaimer in the documentation and/or other
 *    materials provided with the distribution.
 *
 * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
 *    contributors may be used to endorse or promote products derived from this
 *    software without specific prior written permission.
 *
 * 4. This software, with or without modification, must only be used with a
 *    Nordic Semiconductor ASA integrated circuit.
 *
 * 5. Any software provided in binary form under this license must not be reverse
 *    engineered, decompiled, modified and/or disassembled.
 *
 * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */
#include "nrfx_spim.h"
#include "app_util_platform.h"
#include "nrf_gpio.h"
//#include "nrf_gpiote.h"
//#include "nrf_drv_gpiote.h"
#include "nrf_delay.h"
#include "boards.h"
#include "app_error.h"
#include <string.h>
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#define NRFX_SPIM_SCK_PIN  3
#define NRFX_SPIM_MOSI_PIN 4
#define NRFX_SPIM_MISO_PIN 28
#define NRFX_SPIM_SS_PIN   31 //29
#define NRFX_SPIM_DCX_PIN  30

    // APP_SPIS_CS_PIN 31
    // APP_SPIS_MISO_PIN 30
    // APP_SPIS_MOSI_PIN 29
    // APP_SPIS_SCK_PIN 26

#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 TEST_STRING "nordicMaster"
static uint8_t       m_tx_buf[] = TEST_STRING;           /**< TX buffer. */
static uint8_t       m_rx_buf[sizeof(TEST_STRING) + 1];  /**< RX buffer. */
static const uint8_t m_length = sizeof(m_tx_buf);        /**< Transfer length. */

// SPI transfer buffer
/*
static uint8_t       m_tx_buf[] = {128,9,9,9,9,9,9,9,9,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
                                   0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,16,0,0,1};
static uint8_t       m_rx_buf[sizeof(m_tx_buf) + 1];     
static const uint8_t m_length = sizeof(m_tx_buf);      
//static uint16_t      m_length = sizeof(uint8_t)*65;
*/

void spim_event_handler(nrfx_spim_evt_t const * p_event,
                       void *                  p_context)
{
    nrf_gpio_pin_set(NRFX_SPIM_SS_PIN);
    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));
    }
    */
    NRF_LOG_INFO(" Received:");
    NRF_LOG_HEXDUMP_INFO(m_rx_buf, strlen((const char *)m_rx_buf));
}

int main(void)
{
    ret_code_t err_code;
    bsp_board_init(BSP_INIT_LEDS);

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

    nrf_gpio_cfg_output(NRFX_SPIM_SS_PIN);
    nrf_gpio_pin_set(NRFX_SPIM_SS_PIN);

    nrfx_spim_xfer_desc_t xfer_desc = NRFX_SPIM_XFER_TRX(m_tx_buf, m_length, m_rx_buf, m_length);

    nrfx_spim_config_t spi_config = NRFX_SPIM_DEFAULT_CONFIG;
    spi_config.frequency      = NRF_SPIM_FREQ_4M;
    spi_config.ss_pin         = NRFX_SPIM_PIN_NOT_USED;
    //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.dcx_pin        = NRFX_SPIM_PIN_NOT_USED;
    spi_config.use_hw_ss      = true;
    spi_config.ss_active_high = false;
    APP_ERROR_CHECK(nrfx_spim_init(&spi, &spi_config, spim_event_handler, NULL));

    NRF_LOG_INFO("NRFX SPIM example started.");

    while (1)
    {
        nrf_gpio_pin_clear(NRFX_SPIM_SS_PIN);

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

        //APP_ERROR_CHECK(nrfx_spim_xfer_dcx(&spi, &xfer_desc, 0, 15));
        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(500);
    }
}

Thank you for your help, Jared. It definitely helped my sanity (I felt like I was going crazy before) when you pointed out that these examples weren't supposed to work together out of the box.

Kindest regards,

Ryan