Beginner
10 min

Enable SPI communication between electrically isolated sections with 4DIR1421H and PIC18F46K40

Quad-channel SPI communication digital isolator

SPI Isolator 9 Click with EasyPIC v8

Published Jan 14, 2025

Click board™

SPI Isolator 9 Click

Dev. board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18F46K40

SPI communication with high isolation and noise immunity perfect for industrial automation and motor drives

A

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Hardware Overview

How does it work?

SPI Isolator 9 Click is based on the 4DIR1421H, a quad-channel digital isolator from Infineon designed for precise data communication in demanding environments. The device is rated to withstand isolation voltages of up to 5700Vrms and adheres to UL 1577 (Ed. 5) certification standards (certification no. E311313), ensuring compliance with stringent industrial safety requirements. This board has four data channels and ensures robust SPI isolation, making it an ideal solution for systems requiring reliable and safe data transmission across electrically isolated domains. The 4DIR1421H features Infineon's ISOFACE™ Coreless Transformer (CT) technology, which delivers exceptional system noise immunity with a minimum Common Mode Transient Immunity

(CMTI) of 100kV/µs, ensuring stable performance in noisy industrial environments. It supports data rates of up to 40Mbps, allowing for high-speed communication, and operates efficiently with low power consumption, contributing to overall system energy savings. Its robust isolation capabilities make it an excellent choice for Switch-Mode Power Supplies (SMPS) in industrial and telecommunications settings, where safety and reliability are critical, as well as in server and telecom systems, industrial automation, motor drives, and medical devices. This Click board™ is designed in a unique format supporting the newly introduced MIKROE feature called "Click Snap." Unlike the standardized version of Click boards, this feature allows the main IC area to become

movable by breaking the PCB, opening up many new possibilities for implementation. Thanks to the Snap feature, the 4DIR1421H can operate autonomously by accessing its signals directly on the pins marked 1-8. Additionally, the Snap part includes a specified and fixed screw hole position, enabling users to secure the Snap board in their desired location. 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. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

SPI Isolator 9 Click hardware overview image

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC v8 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

EasyPIC v8 horizontal image

Microcontroller Overview

MCU Card / MCU

PIC18F46K40

Architecture

PIC

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3728

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
ID SEL
RE1
RST
SPI Select / ID COMM
RE0
CS
SPI Clock
RC3
SCK
SPI Data OUT
RC4
MISO
SPI Data IN
RC5
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 9 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

EasyPIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyPIC v8 Access DIPMB 1 - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image 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

SPI Isolator 9 Click demo application is developed using the NECTO Studio, ensuring compatibility with mikroSDK's open-source libraries and tools. Designed for plug-and-play implementation and testing, the demo is fully compatible with all development, starter, and mikromedia boards featuring a mikroBUS™ socket.

Example Description
This example demonstrates the use of SPI Isolator 9 Click board by reading the device ID of the connected Accel 22 Click board.

Key functions:

  • spiisolator9_cfg_setup - Config Object Initialization function.

  • spiisolator9_init - Initialization function.

  • spiisolator9_write - This function writes a desired number of data bytes by using SPI serial interface.

  • spiisolator9_read - This function reads a desired number of data bytes by using SPI serial interface.

  • spiisolator9_write_then_read - This function writes and then reads a desired number of data bytes by using SPI serial interface.

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.

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 SPI Isolator 9 Click example
 *
 * # Description
 * This example demonstrates the use of SPI Isolator 9 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 a VCC power supply on the VOUT side.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "spiisolator9.h"

static spiisolator9_t spiisolator9;
static log_t logger;

/**
 * @brief SPI Isolator 9 get accel 22 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 #spiisolator9_t object definition for detailed explanation.
 * @return None.
 * @note None.
 */
void spiisolator9_get_accel22_id ( spiisolator9_t *ctx );

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    spiisolator9_cfg_t spiisolator9_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.
    spiisolator9_cfg_setup( &spiisolator9_cfg );
    SPIISOLATOR9_MAP_MIKROBUS( spiisolator9_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == spiisolator9_init( &spiisolator9, &spiisolator9_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    spiisolator9_get_accel22_id ( &spiisolator9 );
    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 spiisolator9_get_accel22_id ( spiisolator9_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 ( SPIISOLATOR9_OK == spiisolator9_write_then_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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