RE: how to read/write SPI

Bjørn Kvaale — Tue, 31 Jul 2018 08:19:31 GMT

HJkim We have an SPI Master & Slave example in our SDK & good documentation to show how to run the examples. If you have not taken a look at this, it might be useful to start there.

RE: how to read/write SPI

HJkim — Thu, 26 Jul 2018 05:58:35 GMT

Hi, suprtigr

I also have LIS3DH and built your code. but I got following msg

<info> app: Transfer completed.
<info> app: Transfer completed.
<info> app: Received:
<info> app: 80 |.
<info> app: |
<info> app: |

\<info> app: Transfer completed.
<info> app: Transfer completed.
<info> app: Received:
<info> app: 80 |.
<info> app: |
<info> app: |

I think the master (nrt52832) can't read from LIS3DH in your code. Do these logs mean success or error ? It seems there should be y, z, values in a couple of blanks. <info> app: |

RE: how to read/write SPI

suprtigr — Sat, 24 Mar 2018 15:15:06 GMT

Kirt,

If I understand you question, you're asking for more information on how to utilize SPI to read and write with a peripheral device. Firstly you should look into the pca10040.h (supplement your own board number in there) to find the pins to use for SPI, They are labeled SPIM0_MISO_PIN and others of the like. I have just completed this task for my LIS3DH Accelerometer. I was able to write and read from registers. Here is the code I utilized in my main.c file. Note that it is far from the most efficient and elegant solution, but it may help.

/**
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 * All rights reserved.
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 * are permitted provided that the following conditions are met:
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 * 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.
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 * 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 "nrf_drv_spi.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 SPI_INSTANCE  0 /**< SPI instance index. */
static const nrf_drv_spi_t spi = NRF_DRV_SPI_INSTANCE(SPI_INSTANCE);  /**< SPI instance. */
static volatile bool spi_xfer_done;  /**< Flag used to indicate that SPI instance completed the transfer. */
static volatile bool config_done = false;

#define TEST_STRING "Nordic"
//add new definition
//static uint8_t WHO_AM_I_REG = ((uint8_t)143); //10001111 ((uint8_t)0x10) 143 int 0x8F


//MOD BLOCK FOR NEW REG
/**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 uint8_t       m_config_buf1[] = {((uint8_t)0x20),((uint8_t)0x1F)};           /**< TX buffer. */ //,((uint8_t)0x24),((uint8_t)0x40),((uint8_t)0x2E),((uint8_t)0x40)
static uint8_t       m_config_buf2[] = {((uint8_t)0x24),((uint8_t)0x40)}; 
static uint8_t       m_config_buf3[] = {((uint8_t)0x2E),((uint8_t)0x00)}; 

static uint8_t       m_tx_rx_buf1[] = {((uint8_t)0xA0)}; //,((uint8_t)0xA4),((uint8_t)0xAE)
static uint8_t       m_tx_rx_buf2[] = {((uint8_t)0xA4)};
static uint8_t       m_tx_rx_buf3[] = {((uint8_t)0xAE)};

static uint8_t       m_rx_buf1[sizeof(((uint8_t)0xA4)) + 1];    /**< RX buffer. */
static uint8_t       m_rx_buf2[sizeof(((uint8_t)0xA4)) + 1];
static uint8_t       m_rx_buf3[sizeof(((uint8_t)0xA4)) + 1];

//Buffers for accelerometer data
static uint8_t       m_x_axis_buf1[] = {((uint8_t)0xA9)};
static uint8_t       m_x_rx_buf1[sizeof(((uint8_t)0xA9)) + 1]; 

//static const uint8_t m_length_config = sizeof(m_config_buf1);        /**< Transfer length. */
static const uint8_t m_length_rx = sizeof(m_tx_rx_buf1);        /**< Transfer length. */




/**
 * @brief SPI user event handler.
 * @param event
 */
void spi_event_handler(nrf_drv_spi_evt_t const * p_event,
                       void *                    p_context)
{
    spi_xfer_done = true;
    NRF_LOG_INFO("Transfer completed.");
    if (m_rx_buf1[0] != 0||m_rx_buf2[0] != 0||m_rx_buf3[0] != 0||m_x_rx_buf1[0] != 0)
    {
        NRF_LOG_INFO(" Received:");
        NRF_LOG_HEXDUMP_INFO(m_rx_buf1, strlen((const char *)m_rx_buf1));
        NRF_LOG_HEXDUMP_INFO(m_rx_buf2, strlen((const char *)m_rx_buf2));
        NRF_LOG_HEXDUMP_INFO(m_rx_buf3, strlen((const char *)m_rx_buf3));
    }
}

int main(void)
{
    bool verified = false;
    bsp_board_leds_init();

    APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
    NRF_LOG_DEFAULT_BACKENDS_INIT();
    
    NRF_LOG_INFO("SPI example.");

    nrf_drv_spi_config_t spi_config = NRF_DRV_SPI_DEFAULT_CONFIG;
    //FROM pca10040.h
    spi_config.ss_pin   = 12; //SPI_SS_PIN
    spi_config.miso_pin = 28; //SPI_MISO_PIN
    spi_config.mosi_pin = 25; //SPI_MOSI_PIN
    spi_config.sck_pin  = 29; //SPI_SCK_PIN
    APP_ERROR_CHECK(nrf_drv_spi_init(&spi, &spi_config, spi_event_handler, NULL));

    while (1)
    {
        // Reset rx buffer and transfer done flag
        memset(m_rx_buf1, 0, m_length_rx);
        memset(m_rx_buf2, 0, m_length_rx);
        memset(m_rx_buf3, 0, m_length_rx);

        spi_xfer_done = false;

        //moved to config_accel()
        if(!config_done){
          config_accel();
        }

        if(config_done&&!verified){
          APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_rx_buf1, m_length_rx, m_rx_buf1, m_length_rx));
          nrf_delay_ms(200);
          APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_rx_buf2, m_length_rx, m_rx_buf2, m_length_rx));
          nrf_delay_ms(200);
          APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_tx_rx_buf3, m_length_rx, m_rx_buf3, m_length_rx));
          nrf_delay_ms(200);
          verified = true;
        }

        if(verified){
          APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi,m_x_axis_buf1, m_length_rx, m_rx_buf1, m_length_rx));
        }


        while (!spi_xfer_done)
        {
            __WFE();
        }

        NRF_LOG_FLUSH();

        bsp_board_led_invert(BSP_BOARD_LED_0);
        nrf_delay_ms(900);//orig 200
        config_done = true;
    }
}

void config_accel(){
    APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_config_buf1, sizeof(m_config_buf1), NULL, NULL));//change 3rd param from m_rx_buf to NULL & 4th from m_length to NULL 
    nrf_delay_ms(20);
    APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_config_buf2, sizeof(m_config_buf2), NULL, NULL));
    nrf_delay_ms(20);
    APP_ERROR_CHECK(nrf_drv_spi_transfer(&spi, m_config_buf3, sizeof(m_config_buf3), NULL, NULL));
    nrf_delay_ms(20);
}

I hope this helps.