Intermediate
30 min

Achieve galvanic isolation of the SPI interface with MAX22345 and STM32F031K6

Completely isolated SPI interface

SPI Isolator 6 Click with Nucleo 32 with STM32F031K6 MCU

Published Oct 01, 2024

Click board™

SPI Isolator 6 Click

Dev. board

Nucleo 32 with STM32F031K6 MCU

Compiler

NECTO Studio

MCU

STM32F031K6

Create a communication bridge between devices with different power domains

A

A

Hardware Overview

How does it work?

SPI Isolator 6 Click is based on the MAX22345, a four-channel digital isolator with a maximum data rate of 200Mbps from Analog Devices. The MAX22345 provides galvanic isolation for digital signals transmitted between two ground domains and can withstand up to 784Vpeak of continuous isolation and up to 3.75kVRMS for up to 60 seconds. Besides, Analog's proprietary process technology offers the low-power operation, high electromagnetic interference (EMI) immunity, and stable temperature performance.

Both power pins' wide supply voltage range allows the MAX22345 to be used for level translation and isolation. Because this Click board™ represents an isolator for SPI communication, it logically communicates with the MCU precisely through that communication. As already mentioned, the MAX22345 has two power pins for the A and B isolation sides, where it is possible to supply its B side with external voltage in the range of 1.7 to 5.5V by applying it to the terminal marked with VCC_EXT. In addition to the external power supply terminal,

this Click board™ also possesses another two terminals to which the isolated SPI data communication lines are routed. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. However, the Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used for further development.

spi-isolator-6-click-hardware-overview

Features overview

Development board

Nucleo 32 with STM32F031K6 MCU board provides an affordable and flexible platform for experimenting with STM32 microcontrollers in 32-pin packages. Featuring Arduino™ Nano connectivity, it allows easy expansion with specialized shields, while being mbed-enabled for seamless integration with online resources. The

board includes an on-board ST-LINK/V2-1 debugger/programmer, supporting USB reenumeration with three interfaces: Virtual Com port, mass storage, and debug port. It offers a flexible power supply through either USB VBUS or an external source. Additionally, it includes three LEDs (LD1 for USB communication, LD2 for power,

and LD3 as a user LED) and a reset push button. The STM32 Nucleo-32 board is supported by various Integrated Development Environments (IDEs) such as IAR™, Keil®, and GCC-based IDEs like AC6 SW4STM32, making it a versatile tool for developers.

Nucleo 32 with STM32F031K6 MCU double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

ARM Cortex-M0

MCU Memory (KB)

32

Silicon Vendor

STMicroelectronics

Pin count

32

RAM (Bytes)

4096

You complete me!

Accessories

Click Shield for Nucleo-32 is the perfect way to expand your development board's functionalities with STM32 Nucleo-32 pinout. The Click Shield for Nucleo-32 provides two mikroBUS™ sockets to add any functionality from our ever-growing range of Click boards™. We are fully stocked with everything, from sensors and WiFi transceivers to motor control and audio amplifiers. The Click Shield for Nucleo-32 is compatible with the STM32 Nucleo-32 board, providing an affordable and flexible way for users to try out new ideas and quickly create prototypes with any STM32 microcontrollers, choosing from the various combinations of performance, power consumption, and features. The STM32 Nucleo-32 boards do not require any separate probe as they integrate the ST-LINK/V2-1 debugger/programmer and come with the STM32 comprehensive software HAL library and various packaged software examples. This development platform provides users with an effortless and common way to combine the STM32 Nucleo-32 footprint compatible board with their favorite Click boards™ in their upcoming projects.

Click Shield for Nucleo-32 accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
PA4
CS
SPI Clock
PB3
SCK
SPI Data OUT
PB4
MISO
SPI Data IN
PB5
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

SPI Isolator 6 Click Schematic schematic

Step by step

Project assembly

Click Shield for Nucleo-144 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Nucleo 32 with STM32F031K6 MCU as your development board.

Click Shield for Nucleo-144 front image hardware assembly
Nucleo 144 with STM32L4A6ZG MCU front image hardware assembly
Stepper 22 Click front image hardware assembly
Prog-cut hardware assembly
Stepper 22 Click complete accessories setup image hardware assembly
Nucleo-32 with STM32 MCU Access MB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
Necto image step 5 hardware assembly
Necto image step 6 hardware assembly
STM32 M4 Clicker HA MCU/Select Step hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for SPI Isolator 6 Click driver.

Key functions:

  • spiisolator6_generic_write This function writes a desired number of data bytes by using SPI serial interface.

  • spiisolator6_generic_read This function writes and then reads a desired number of data bytes by using SPI serial interface.

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * @file main.c
 * @brief SPIIsolator6 Click example
 *
 * # Description
 * This example demonstrates the use of SPI Isolator 6 Click board by reading the
 * device ID of the connected Accel 22 Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger.
 *
 * ## Application Task
 * Reads and checks the device ID of the connected Accel 22 Click board, and displays the
 * results on the USB UART approximately once per second.
 *
 * @note
 * Make sure to provide VCC power supply on VCC-EXT pin.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "spiisolator6.h"

static spiisolator6_t spiisolator6;
static log_t logger;

/**
 * @brief SPI Isolator 6 get accel 22 device id function.
 * @details This function reads and checks the device ID of the connected Accel 22 Click board.
 * @param[in] ctx : Click context object.
 * See #spiisolator6_t object definition for detailed explanation.
 * @return None.
 * @note None.
 */
void spiisolator6_get_accel22_device_id ( spiisolator6_t *ctx );

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    spiisolator6_cfg_t spiisolator6_cfg;  /**< Click config object. */

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, " Application Init " );

    // Click initialization.
    spiisolator6_cfg_setup( &spiisolator6_cfg );
    SPIISOLATOR6_MAP_MIKROBUS( spiisolator6_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == spiisolator6_init( &spiisolator6, &spiisolator6_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    spiisolator6_get_accel22_device_id ( &spiisolator6 );
    Delay_ms ( 1000 );
}

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

    return 0;
}

void spiisolator6_get_accel22_device_id ( spiisolator6_t *ctx )
{
    #define DEVICE_NAME             "Accel 22 Click"
    #define DEVICE_SPI_READ_REG     0x0B
    #define DEVICE_REG_ID           0x00
    #define DEVICE_ID               0xAD
    uint8_t data_in[ 2 ] = { DEVICE_SPI_READ_REG, DEVICE_REG_ID };
    uint8_t device_id;
    if ( SPIISOLATOR6_OK == spiisolator6_generic_read ( ctx, data_in, 2, &device_id, 1 ) )
    {
        log_printf( &logger, "\r\n %s\r\n", ( char * ) DEVICE_NAME );
        if ( DEVICE_ID == device_id )
        {
            log_printf ( &logger, " Device ID: 0x%.2X\r\n", ( uint16_t ) device_id );
        }
        else
        {
            log_error( &logger, " Wrong Device ID: 0x%.2X", ( uint16_t ) device_id );
        }
    }
}

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

Additional Support

Resources

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