SPI

Introduction

The MikroSDK.Driver.SPI.Master library provides a standardized API for controlling SPI peripherals in master mode on microcontrollers. This documentation covers the essential functions, data structures, and examples needed to effectively use the SPI Master driver in your projects.

SPI (Serial Peripheral Interface) is a synchronous serial communication protocol used for short-distance communication, primarily in embedded systems. It is commonly used for communication with sensors, displays, and other peripherals. The MikroSDK.Driver.SPI.Master library simplifies the integration of SPI master functionality by providing a consistent API to configure, transmit, and receive data over SPI.

API Name

• MikroSDK.Driver.SPI.Master

API Files

• GitHub Repository:

  • Header file
  • Source file
  • Configuration (CMake) file

Prerequisites

• Library Manager:

  • Select Driver.SPI.Master to add the API to your project using the Library Manager in NECTO Studio.

• Headers:

  • Include the Driver.SPI.Master header in your source files to access the SPI functions.
  • This header pops up in the lower right part of NECTO Studio once you perform the previous task (while selecting Driver.SPI.Master in Library Manager)
  • Alternatively, include the drv_spi_master.h header in your source files to access the SPI functions.

• CMakeLists:

  • You do not have to perform anything, configuration (CMake) file is already taken care of automatically while you performed the first task in this Prerequisites!
  • You can ensure that your CMakeLists.txt includes the necessary configurations to link against the MikroSDK.Driver.SPI.Master library.

Code Examples

• How to properly test SPI?

/* Project name:
 *   SPI demo
 * Copyright:
 *   (c) MIKROE, 2024.
 * Description:
 *   Example is meant for demonstrating SPI functionality using mikroSDK 2.0.
 *   Make sure to place [SRAM Click](https://www.mikroe.com/sram-click)
 *   in mikroBUS1 and [TESTER Click](https://www.mikroe.com/tester-click) in mikroBUS2.
 *   Pin MIKROBUS_2_INT is set to high if transfer was successful. Written and read data
 *   is also printed out on the Standard output (determined by the chosen setup).
 *   Use a logic analyzer for more detailed insight into the transfer details.
 * Library dependencies?
 *   - Make sure `Driver.SPI.Master`, `Driver.GPIO.Out`, `Log` and `Board`
 *     libraries are enabled in NECTO's Library Manager to ensure a successful
 *     build.
 */

/**
 * @brief For a detailed explanation of this demo, please visit:
 * <https://libstock.mikroe.com/projects/view/5397/spi-demo>
 */

// ------------------------------------------------------------------ INCLUDES

/**
 * Any initialization code needed for MCU to function properly.
 * Do not remove this line or clock might not be set correctly.
 */
#ifdef PREINIT_SUPPORTED
#include "preinit.h"
#endif

#include "MikroSDK.Driver.GPIO.Out"
#include "MikroSDK.Board"
#include "MikroSDK.Log"
#include "MikroSDK.Driver.SPI.Master"

#ifdef MikroCCoreVersion
    #if MikroCCoreVersion >= 1
        #include "delays.h"
    #endif
#endif

// -------------------------------------------------------------------- MACROS
// Return value in case of error.
#define RET_FAIL (-1)
#define RET_SUCCESS (0)

// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_CS
#define MIKROBUS_1_CS NC
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_SCK
#define MIKROBUS_1_SCK NC
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MISO
#define MIKROBUS_1_MISO NC
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MOSI
#define MIKROBUS_1_MOSI NC
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_2_INT
#define MIKROBUS_2_INT NC
#endif

// SPI pins
#define TEST_PIN_SPI_CS   MIKROBUS_1_CS
#define TEST_PIN_SPI_SCK  MIKROBUS_1_SCK
#define TEST_PIN_SPI_MISO MIKROBUS_1_MISO
#define TEST_PIN_SPI_MOSI MIKROBUS_1_MOSI

// SRAM Click specific macros.
#define DATA_LENGTH (20)

// WRITE instruction
#define SRAM_CLICK_WRITE_CMD (2)

// READ instruction
#define SRAM_CLICK_READ_CMD (3)

// Write sequence consists of:
// WRITE instruction, 24-bit address (3 bytes) and data to be written (5 bytes total)
#define SRAM_CLICK_WRITE_DATA_LENGTH (5)

// Read sequence consists of:
// READ instruction and 24-bit address (3 bytes) (4 bytes total)
#define SRAM_CLICK_WRITE_READ_DATA_LENGTH (4)

// Dummy write data for this click
#define SRAM_CLICK_DEFAULT_WRITE_DATA (0)

// SPI speed
#define SRAM_CLICK_SPEED (100000)

#define signal_success(port,pin) digital_out_init( &port, pin ); \
                                 digital_out_write( &port, 1 )

// ----------------------------------------------------------------- VARIABLES
static digital_out_t output_pin;

static spi_master_t sram_click;
static spi_master_config_t sram_click_config;

// SRAM Click specific variables.
// Array for data to be written - SRAM Click.
static uint8_t write_buffer[DATA_LENGTH];

// Array for data to be read - SRAM Click.
static uint8_t read_buffer[DATA_LENGTH];

static log_t logger;
static log_cfg_t logger_cfg;
// ----------------------------------------------------------------- USER CODE
// SRAM Click Write procedure.
int8_t sram_click_write(uint32_t address, uint8_t data_to_be_written) {
    // Local array for storing appropriate data, which will be sent to SRAM Click.
    uint8_t local_array[SRAM_CLICK_WRITE_DATA_LENGTH];

    memset( &local_array, sizeof( local_array ), 0 );

    // Write sequence - WRITE instruction, 24-bit address and data to be written.
    local_array[0] = SRAM_CLICK_WRITE_CMD;
    local_array[1] = address >> 16;
    local_array[2] = address >> 8;
    local_array[3] = address;
    local_array[4] = data_to_be_written;

    // Select SRAM Click.
    spi_master_select_device(TEST_PIN_SPI_CS);

    // Write data to SRAM Click.
    if( SPI_MASTER_ERROR == spi_master_write(&sram_click, local_array, SRAM_CLICK_WRITE_DATA_LENGTH)) {
        log_printf( &logger, "SPI master write failed.\n" );
        return RET_FAIL;
    }

    // Deselect SRAM Click.
    spi_master_deselect_device(TEST_PIN_SPI_CS);

    return RET_SUCCESS;
}

// SRAM Click Read procedure.
int8_t sram_click_read( uint32_t address ) {
    // Local array for storing appropriate data, which will be sent to SRAM Click.
    uint8_t local_array[4];

    memset( &local_array, sizeof( local_array ), 0 );

    // Read sequence - READ instruction and 24-bit address.
    local_array[0] = SRAM_CLICK_READ_CMD;
    local_array[1] = address >> 16;
    local_array[2] = address >> 8;
    local_array[3] = address;

    // Select SRAM Click.
    spi_master_select_device(TEST_PIN_SPI_CS);

    // Write data to SRAM Click.
    if( SPI_MASTER_ERROR == spi_master_write_then_read( &sram_click, local_array, SRAM_CLICK_WRITE_READ_DATA_LENGTH, read_buffer, DATA_LENGTH )) {
        log_printf( &logger, "SPI master write then read failed.\n" );
        return RET_FAIL;
    }

    // Deselect SRAM Click.
    spi_master_deselect_device( TEST_PIN_SPI_CS );

    return RET_SUCCESS;
}

// Application initialization procedure.
int8_t application_init() {
    // Initialize logger.
    LOG_MAP_USB_UART( logger_cfg );
    log_init( &logger, &logger_cfg );

    // Set default properties for SRAM Click.
    spi_master_configure_default( &sram_click_config );

    // Set desired basic properties for SRAM Click which is on mikroBUS1.
    sram_click_config.sck = TEST_PIN_SPI_SCK;
    sram_click_config.miso = TEST_PIN_SPI_MISO;
    sram_click_config.mosi = TEST_PIN_SPI_MOSI;
    sram_click_config.speed = SRAM_CLICK_SPEED;
    sram_click_config.mode = SPI_MASTER_MODE_DEFAULT;
    sram_click_config.default_write_data = SRAM_CLICK_DEFAULT_WRITE_DATA;

    if( ACQUIRE_FAIL == spi_master_open(&sram_click, &sram_click_config)) {
        log_printf( &logger, "SPI master open failed.\n" );
        return RET_FAIL;
    }

    // Set Chip Select polarity (SRAM Click requires active low).
    spi_master_set_chip_select_polarity(SPI_MASTER_CHIP_SELECT_DEFAULT_POLARITY);

    // Set desired default write (dummy) data.
    if( SPI_MASTER_ERROR == spi_master_set_default_write_data(&sram_click, SRAM_CLICK_DEFAULT_WRITE_DATA)) {
        log_printf( &logger, "SPI master set default write failed.\n" );
        return RET_FAIL;
    }

    // Set desired baud rate (speed).
    if( SPI_MASTER_ERROR == spi_master_set_speed(&sram_click, SRAM_CLICK_SPEED)) {
        log_printf( &logger, "SPI master set speed failed.\n" );
        return RET_FAIL;
    }

    // Set desired mode (SRAM Click requires mode 0).
    if( SPI_MASTER_ERROR == spi_master_set_mode(&sram_click, SPI_MASTER_MODE_DEFAULT)) {
        log_printf( &logger, "SPI master set mode failed.\n" );
        return RET_FAIL;
    }

    return RET_SUCCESS;
}

// Application task procedure.
int8_t application_task() {
    uint8_t address_and_data = 0;

    log_printf( &logger, "Written data:\n");
    // Write sequence - SRAM Click.
    for (address_and_data = 0; address_and_data < DATA_LENGTH; address_and_data++) {

        // Write data via SPI protocol.
        if( RET_FAIL == sram_click_write(address_and_data, address_and_data)) {
            log_printf( &logger, "SPI master write failed.\n" );
            return RET_FAIL;
        }

        write_buffer[address_and_data] = address_and_data;

        if( DATA_LENGTH - 1 != address_and_data ) {
            log_printf( &logger, "%d, ", (uint16_t)write_buffer[address_and_data] );
        } else {
            log_printf( &logger, "%d\n", (uint16_t)write_buffer[address_and_data] );
        }

        Delay_ms(1);
    }

    // Read data from SRAM Click.
    if( RET_FAIL == sram_click_read(0)) {
        log_printf( &logger, "SPI master read failed.\n" );
        return RET_FAIL;
    }

    log_printf( &logger, "Read data:\n" );
    for( address_and_data = 0; address_and_data < DATA_LENGTH; address_and_data++ ) {
        if( DATA_LENGTH - 1 != address_and_data ) {
            log_printf( &logger, "%d, ", (uint16_t)read_buffer[address_and_data] );
        } else {
            log_printf( &logger, "%d\n", (uint16_t)read_buffer[address_and_data] );
        }
    }

    /*
     *  memcmp compares buffers and returns 0 if they are the same.
     *  So, here, if it does return 0, it means that the transfer
     *  was successful and signal_success should set output_pin to high.
     */
    if ( !memcmp(write_buffer, read_buffer, sizeof( read_buffer ))) {
        signal_success( output_pin, MIKROBUS_2_INT );
    }

    // Erase object instance configuration for SRAM Click.
    if( SPI_MASTER_ERROR == spi_master_close( &sram_click )) {
        log_printf( &logger, "SPI master close failed.\n" );
        return RET_FAIL;
    }

    return RET_SUCCESS;
}

int main(void) {
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif

    // Initialize necessary SPI protocol properties.
    if( RET_FAIL == application_init()) {
        log_printf( &logger, "Application init failed.\n" );
        return RET_FAIL;
    }

    // Write, read, then subsequently display results on test pin.
    if( RET_FAIL == application_task()) {
        log_printf( &logger, "Application task failed.\n" );
        return RET_FAIL;
    }

    log_printf( &logger, "End of SPI demo.\n" );

    return RET_SUCCESS;
}

// ----------------------------------------------------------------------- END

• How do I initialize the SPI Master driver with default settings?

/* Project name:
 *   How do I initialize the SPI Master driver with default settings?
 * Copyright:
 *   (c) MIKROE, 2024.
 * Description:
 *   Example is meant for demonstrating SPI functionality using mikroSDK 2.0.
 *   SPI master protocol shall be initialized with common day-to-day settings.
 * Library dependencies?
 *   - Make sure `Driver.SPI.Master`, `Driver.GPIO.Out`, `Log` and `Board`
 *     libraries are enabled in NECTO's Library Manager to ensure a successful
 *     build.
 */

// ------------------------------------------------------------------ INCLUDES

/**
 * Any initialization code needed for MCU to function properly.
 * Do not remove this line or clock might not be set correctly.
 */
#ifdef PREINIT_SUPPORTED
#include "preinit.h"
#endif

#include "MikroSDK.Driver.SPI.Master"
#include "MikroSDK.Board"
#include "MikroSDK.Log"

#ifdef MikroCCoreVersion
    #if MikroCCoreVersion >= 1
        #include "delays.h"
    #endif
#endif

// -------------------------------------------------------------------- MACROS
// Return value in case of error.
#define RET_FAIL (-1)
#define RET_SUCCESS (0)

// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_SCK
#define MIKROBUS_1_SCK NC // example: replace `NC` with `PA0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MISO
#define MIKROBUS_1_MISO NC // example: replace `NC` with `PB5`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MOSI
#define MIKROBUS_1_MOSI NC // example: replace `NC` with `PC0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_2_INT
#define MIKROBUS_2_INT NC // example: replace `NC` with `PD5`
#endif

// Dummy SPI write data
#define SPI_DEFAULT_TRANSFER_DATA (0)

// SPI speed
#define SPI_SPEED (100000)

// ----------------------------------------------------------------- VARIABLES
static spi_master_t obj;
static spi_master_config_t obj_config;

static log_t logger;
static log_cfg_t logger_cfg;

// ----------------------------------------------------------------- USER CODE
// SPI protocol initialization procedure
int8_t spi_protocol_init() {
    // Initialize logger
    LOG_MAP_USB_UART( logger_cfg );
    log_init( &logger, &logger_cfg );

    // Set default properties
    spi_master_configure_default( &obj_config );
    log_printf( &logger, "SPI master set default properties successful.\n" );

    // Set desired basic properties for SPI protocol on mikroBUS slot 1
    obj_config.sck = MIKROBUS_1_SCK;
    obj_config.miso = MIKROBUS_1_MISO;
    obj_config.mosi = MIKROBUS_1_MOSI;
    obj_config.speed = SPI_SPEED;
    obj_config.mode = SPI_MASTER_MODE_DEFAULT;
    obj_config.default_write_data = SPI_DEFAULT_TRANSFER_DATA;

    if( ACQUIRE_FAIL == spi_master_open(&obj, &obj_config)) {
        log_printf( &logger, "SPI master open failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master open successful.\n" );

    // Set Chip Select polarity (most of the
    // [Click boards](https://www.mikroe.com/click-boards) require active low)
    spi_master_set_chip_select_polarity(SPI_MASTER_CHIP_SELECT_DEFAULT_POLARITY);

    // Set desired default write (dummy) data
    if( SPI_MASTER_ERROR == spi_master_set_default_write_data(&obj, obj_config.default_write_data)) {
        log_printf( &logger, "SPI master set default write failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master set default write successful.\n" );

    // Set desired baud rate (speed)
    if( SPI_MASTER_ERROR == spi_master_set_speed(&obj, obj_config.speed)) {
        log_printf( &logger, "SPI master set speed failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master set speed successful.\n" );

    // Set desired mode
    if( SPI_MASTER_ERROR == spi_master_set_mode(&obj, obj_config.mode)) {
        log_printf( &logger, "SPI master set mode failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master set mode successful.\n" );

    return RET_SUCCESS;
}

int main(void) {
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif

    // Initialize necessary SPI protocol properties.
    if( RET_FAIL == spi_protocol_init()) {
        log_printf( &logger, "SPI init failed.\n" );
        return RET_FAIL;
    }

    log_printf( &logger, "SPI init successful.\n" );

    return RET_SUCCESS;
}

// ----------------------------------------------------------------------- END

• How do I set the SPI communication speed?

/* Project name:
 *   How do I set the SPI communication speed?
 * Copyright:
 *   (c) MIKROE, 2024.
 * Description:
 *   Example is meant for demonstrating SPI functionality using mikroSDK 2.0.
 *   Baud rate of SPI master protocol shall be configured.
 * Library dependencies?
 *   - Make sure `Driver.SPI.Master`, `Driver.GPIO.Out`, `Log` and `Board`
 *     libraries are enabled in NECTO's Library Manager to ensure a successful
 *     build.
 */

// ------------------------------------------------------------------ INCLUDES

/**
 * Any initialization code needed for MCU to function properly.
 * Do not remove this line or clock might not be set correctly.
 */
#ifdef PREINIT_SUPPORTED
#include "preinit.h"
#endif

#include "MikroSDK.Driver.SPI.Master"
#include "MikroSDK.Board"
#include "MikroSDK.Log"

#ifdef MikroCCoreVersion
    #if MikroCCoreVersion >= 1
        #include "delays.h"
    #endif
#endif

// -------------------------------------------------------------------- MACROS
// Return value in case of error.
#define RET_FAIL (-1)
#define RET_SUCCESS (0)

// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_SCK
#define MIKROBUS_1_SCK NC // example: replace `NC` with `PA0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MISO
#define MIKROBUS_1_MISO NC // example: replace `NC` with `PB5`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MOSI
#define MIKROBUS_1_MOSI NC // example: replace `NC` with `PC0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_2_INT
#define MIKROBUS_2_INT NC // example: replace `NC` with `PD5`
#endif

// Dummy SPI write data
#define SPI_DEFAULT_TRANSFER_DATA (0)

// SPI speed
#define SPI_SPEED (100000)

// ----------------------------------------------------------------- VARIABLES
static spi_master_t obj;
static spi_master_config_t obj_config;

static log_t logger;
static log_cfg_t logger_cfg;

// ----------------------------------------------------------------- USER CODE

int main(void) {
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif

    // Initialize logger
    LOG_MAP_USB_UART( logger_cfg );
    log_init( &logger, &logger_cfg );

    // Set default properties
    spi_master_configure_default( &obj_config );
    log_printf( &logger, "SPI master set default properties successful.\n" );

    // Set desired basic properties for SPI protocol on mikroBUS slot 1
    obj_config.sck = MIKROBUS_1_SCK;
    obj_config.miso = MIKROBUS_1_MISO;
    obj_config.mosi = MIKROBUS_1_MOSI;
    obj_config.speed = SPI_SPEED;
    obj_config.mode = SPI_MASTER_MODE_DEFAULT;
    obj_config.default_write_data = SPI_DEFAULT_TRANSFER_DATA;

    if( ACQUIRE_FAIL == spi_master_open(&obj, &obj_config)) {
        log_printf( &logger, "SPI master open failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master open successful.\n" );

    // Set desired baud rate (speed)
    if( SPI_MASTER_ERROR == spi_master_set_speed(&obj, obj_config.speed)) {
        log_printf( &logger, "SPI master set speed failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master set speed successful.\n" );

    return RET_SUCCESS;

}

// ----------------------------------------------------------------------- END

• How do I configure the SPI Master to use MODE 1?

/* Project name:
 *   How do I configure the SPI Master to use MODE 1?
 * Copyright:
 *   (c) MIKROE, 2024.
 * Description:
 *   Example is meant for demonstrating SPI functionality using mikroSDK 2.0.
 *   Mode of operation of SPI master protocol shall be configured to MODE 1.
 * Library dependencies?
 *   - Make sure `Driver.SPI.Master`, `Driver.GPIO.Out`, `Log` and `Board`
 *     libraries are enabled in NECTO's Library Manager to ensure a successful
 *     build.
 */

// ------------------------------------------------------------------ INCLUDES

/**
 * Any initialization code needed for MCU to function properly.
 * Do not remove this line or clock might not be set correctly.
 */
#ifdef PREINIT_SUPPORTED
#include "preinit.h"
#endif

#include "MikroSDK.Driver.SPI.Master"
#include "MikroSDK.Board"
#include "MikroSDK.Log"

#ifdef MikroCCoreVersion
    #if MikroCCoreVersion >= 1
        #include "delays.h"
    #endif
#endif

// -------------------------------------------------------------------- MACROS
// Return value in case of error.
#define RET_FAIL (-1)
#define RET_SUCCESS (0)

// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_SCK
#define MIKROBUS_1_SCK NC // example: replace `NC` with `PA0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MISO
#define MIKROBUS_1_MISO NC // example: replace `NC` with `PB5`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MOSI
#define MIKROBUS_1_MOSI NC // example: replace `NC` with `PC0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_2_INT
#define MIKROBUS_2_INT NC // example: replace `NC` with `PD5`
#endif

// Dummy SPI write data
#define SPI_DEFAULT_TRANSFER_DATA (0)

// SPI speed
#define SPI_SPEED (100000)

// ----------------------------------------------------------------- VARIABLES
static spi_master_t obj;
static spi_master_config_t obj_config;

static log_t logger;
static log_cfg_t logger_cfg;

// ----------------------------------------------------------------- USER CODE

int main(void) {
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif

    // Initialize logger
    LOG_MAP_USB_UART( logger_cfg );
    log_init( &logger, &logger_cfg );

    // Set default properties
    spi_master_configure_default( &obj_config );
    log_printf( &logger, "SPI master set default properties successful.\n" );

    // Set desired basic properties for SPI protocol on mikroBUS slot 1
    obj_config.sck = MIKROBUS_1_SCK;
    obj_config.miso = MIKROBUS_1_MISO;
    obj_config.mosi = MIKROBUS_1_MOSI;
    obj_config.speed = SPI_SPEED;
    obj_config.mode = SPI_MASTER_MODE_1;
    obj_config.default_write_data = SPI_DEFAULT_TRANSFER_DATA;

    if( ACQUIRE_FAIL == spi_master_open(&obj, &obj_config)) {
        log_printf( &logger, "SPI master open failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master open successful.\n" );

    // Set desired mode
    if( SPI_MASTER_ERROR == spi_master_set_mode(&obj, obj_config.mode)) {
        log_printf( &logger, "SPI master set mode failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master set mode successful.\n" );

    return RET_SUCCESS;
}

// ----------------------------------------------------------------------- END

• How do I set the default write data for the SPI Master?

/* Project name:
 *   How do I set the default write data for the SPI Master?
 * Copyright:
 *   (c) MIKROE, 2024.
 * Description:
 *   Example is meant for demonstrating SPI functionality using mikroSDK 2.0.
 *   Default write data of SPI master protocol shall be configured.
 * Library dependencies?
 *   - Make sure `Driver.SPI.Master`, `Driver.GPIO.Out`, `Log` and `Board`
 *     libraries are enabled in NECTO's Library Manager to ensure a successful
 *     build.
 */

// ------------------------------------------------------------------ INCLUDES

/**
 * Any initialization code needed for MCU to function properly.
 * Do not remove this line or clock might not be set correctly.
 */
#ifdef PREINIT_SUPPORTED
#include "preinit.h"
#endif

#include "MikroSDK.Driver.SPI.Master"
#include "MikroSDK.Board"
#include "MikroSDK.Log"

#ifdef MikroCCoreVersion
    #if MikroCCoreVersion >= 1
        #include "delays.h"
    #endif
#endif

// -------------------------------------------------------------------- MACROS
// Return value in case of error.
#define RET_FAIL (-1)
#define RET_SUCCESS (0)

// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_SCK
#define MIKROBUS_1_SCK NC // example: replace `NC` with `PA0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MISO
#define MIKROBUS_1_MISO NC // example: replace `NC` with `PB5`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_1_MOSI
#define MIKROBUS_1_MOSI NC // example: replace `NC` with `PC0`
#endif
// If hardware without mikroBUS socket is used, make sure to define adequate pin.
#ifndef MIKROBUS_2_INT
#define MIKROBUS_2_INT NC // example: replace `NC` with `PD5`
#endif

// Dummy SPI write data
#define SPI_DEFAULT_TRANSFER_DATA (0) // example: it could be (0xFF) as well

// SPI speed
#define SPI_SPEED (100000)

// ----------------------------------------------------------------- VARIABLES
static spi_master_t obj;
static spi_master_config_t obj_config;

static log_t logger;
static log_cfg_t logger_cfg;

// ----------------------------------------------------------------- USER CODE

int main(void) {
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif

    // Initialize logger
    LOG_MAP_USB_UART( logger_cfg );
    log_init( &logger, &logger_cfg );

    // Set default properties
    spi_master_configure_default( &obj_config );
    log_printf( &logger, "SPI master set default properties successful.\n" );

    // Set desired basic properties for SPI protocol on mikroBUS slot 1
    obj_config.sck = MIKROBUS_1_SCK;
    obj_config.miso = MIKROBUS_1_MISO;
    obj_config.mosi = MIKROBUS_1_MOSI;
    obj_config.speed = SPI_SPEED;
    obj_config.mode = SPI_MASTER_MODE_1;
    obj_config.default_write_data = SPI_DEFAULT_TRANSFER_DATA;

    if( ACQUIRE_FAIL == spi_master_open(&obj, &obj_config)) {
        log_printf( &logger, "SPI master open failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master open successful.\n" );

    // Set desired default write (dummy) data
    if( SPI_MASTER_ERROR == spi_master_set_default_write_data(&obj, obj_config.default_write_data)) {
        log_printf( &logger, "SPI master set default write failed.\n" );
        return RET_FAIL;
    }
    log_printf( &logger, "SPI master set default write successful.\n" );

    return RET_SUCCESS;
}

// ----------------------------------------------------------------------- END

• How do I select an SPI slave device using a chip select pin?

/* Project name:
 *   How do I select an SPI slave device (peripheral) using a chip select pin?
 * Copyright:
 *   (c) MIKROE, 2024.
 * Description:
 *   Example is meant for demonstrating SPI functionality using mikroSDK 2.0.
 *   Selection (`spi_master_select_device` functionality) and deselection
 *   (`spi_master_deselect_device` functionality) of an SPI peripheral
 *   shall be performed.
 *   Simulation of writing a byte sequence via SPI protocol shall be performed.
 *   Simulation of reading a byte sequence via SPI protocol shall be performed.
 * Library dependencies?
 *   - Make sure `Driver.SPI.Master`, `Log` and `Board`
 *     libraries are enabled in NECTO's Library Manager to ensure a successful
 *     build.
 * NOTE: This example depicts selection and deselection of an SPI peripheral
 *       [SRAM Click](https://www.mikroe.com/sram-click).
 *       The user needs to perform initialization of an SPI protocol prior
 *       to manipulation of the SRAM Click.
 *       The user needs to create `main` functionality.
 *       This example WILL NOT work out-of-the-box for the other SPI
 *       peripherals.
 */

// ------------------------------------------------------------------ INCLUDES

#include "MikroSDK.Driver.SPI.Master"
#include "MikroSDK.Board"
#include "MikroSDK.Log"

// -------------------------------------------------------------------- MACROS
// Return value in case of error
#define RET_FAIL (-1)
#define RET_SUCCESS (0)

// If hardware without mikroBUS socket is used, make sure to define adequate pin
#ifndef MIKROBUS_1_CS
#define MIKROBUS_1_CS NC
#endif

// SPI Chip Select pin
#define TEST_PIN_SPI_CS   MIKROBUS_1_CS

// SRAM Click specific macros
#define DATA_LENGTH (20)

// SRAM Click WRITE instruction
#define SRAM_CLICK_WRITE_CMD (2)

// SRAM Click READ instruction
#define SRAM_CLICK_READ_CMD (3)

// SRAM Click Write sequence consists of:
// WRITE instruction, 24-bit address (3 bytes) and data to be written (5 bytes total)
#define SRAM_CLICK_WRITE_DATA_LENGTH (5)

// SRAM Click Read sequence consists of:
// READ instruction and 24-bit address (3 bytes) (4 bytes total)
#define SRAM_CLICK_WRITE_READ_DATA_LENGTH (4)

// ----------------------------------------------------------------- VARIABLES
static spi_master_t sram_click;

// SRAM Click specific variables
// Array for data to be written to SRAM Click
static uint8_t write_buffer[DATA_LENGTH];

// Array for data to be read from SRAM Click
static uint8_t read_buffer[DATA_LENGTH];

// ----------------------------------------------------------------- USER CODE
// SRAM Click Write procedure
int8_t sram_click_write(uint32_t address, uint8_t data_to_be_written) {
    // Local array for storing appropriate data, which will be sent to SRAM Click
    uint8_t local_array[SRAM_CLICK_WRITE_DATA_LENGTH];

    memset( &local_array, sizeof( local_array ), 0 );

    // Write sequence - WRITE instruction, 24-bit address and data to be written
    local_array[0] = SRAM_CLICK_WRITE_CMD;
    local_array[1] = address >> 16;
    local_array[2] = address >> 8;
    local_array[3] = address;
    local_array[4] = data_to_be_written;

    // Select SRAM Click
    spi_master_select_device(TEST_PIN_SPI_CS);

    // Write data to SRAM Click
    if( SPI_MASTER_ERROR == spi_master_write(&sram_click, local_array,
                                        SRAM_CLICK_WRITE_DATA_LENGTH)) {
        return RET_FAIL;
    }

    // Deselect SRAM Click
    spi_master_deselect_device(TEST_PIN_SPI_CS);

    return RET_SUCCESS;
}

// SRAM Click Read procedure
int8_t sram_click_read( uint32_t address ) {
    // Local array for storing appropriate data,
    // which will be sent to SRAM Click
    uint8_t local_array[4];

    memset( &local_array, sizeof( local_array ), 0 );

    // Read sequence - READ instruction and 24-bit address
    local_array[0] = SRAM_CLICK_READ_CMD;
    local_array[1] = address >> 16;
    local_array[2] = address >> 8;
    local_array[3] = address;

    // Select SRAM Click
    spi_master_select_device(TEST_PIN_SPI_CS);

    // Write data to SRAM Click
    if( SPI_MASTER_ERROR == spi_master_write_then_read( &sram_click,
                                                        local_array,
                                                        SRAM_CLICK_WRITE_READ_DATA_LENGTH,
                                                        read_buffer,
                                                        DATA_LENGTH )) {
        return RET_FAIL;
    }

    // Deselect SRAM Click
    spi_master_deselect_device( TEST_PIN_SPI_CS );

    return RET_SUCCESS;
}

// ----------------------------------------------------------------------- END

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