Beginner
10 min
0

Keep CAN communication secure with MAX14882 and STM32F373RC

Enhance the reliability and performance of the CAN bus in challenging environments

CAN Isolator 3 Click with UNI Clicker

Published Dec 09, 2023

Click board™

CAN Isolator 3 Click

Development board

UNI Clicker

Compiler

NECTO Studio

MCU

STM32F373RC

Provide protection from overvoltage transients between the CAN bus cable network and the systems connected to it

A

A

Hardware Overview

How does it work?

CAN Isolator 3 Click is based on MAX14882, an isolated CAN transceiver with an integrated transformer driver from Analog Devices. Its features include a wide supply voltage range for the CAN controller interface (3V – 5V), field bus polarity control (POL), an integrated transformer driver for power transfer to the bus side, and an integrated LDO for powering the CAN bus side. The CAN bus controller exceeds the ISO 11898 specifications requirement of -2V to +7V with ±25V receiver input common-mode range. Additionally, the CANH and CANL IOs are fault tolerant up to ±54V and protected from electronic discharge (ESD) up to ±15KV to GNDB on the bus side. CAN

Isolator 3 Click is equipped with CAN and VISO terminals, where the VISO terminal can be a bus-side power input or an LDO power output terminal. If used as an LDO power output, you can count up to 5V of VDDB voltage on this terminal. You can select the input/output direction over the VISO DIR jumper, where the isolated voltage as output (OUT) is set by default. In this default configuration, the reinforced insulation module can supply to the VISO terminal 3.3V or 5V, depending on the selected voltage on the VCC SEL jumper, as the 3.3V is selected by default. CAN Isolator 3 Click uses a standard UART serial interface to communicate with the host MCU over

commonly used UART RX and TX pins. The RX and TX are also available on a separate header for testing purposes. The polarity of the CAN controller can be set over the POL pin with a LOW logic state for normal CANH and CANL operation and HIGH to swap the functions of the CANH and CANL. 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.

CAN Isolator 3 Click hardware overview image

Features overview

Development board

UNI Clicker is a compact development board designed as a complete solution that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It supports a wide range of microcontrollers, such as different ARM, PIC32, dsPIC, PIC, and AVR from various vendors like Microchip, ST, NXP, and TI (regardless of their number of pins), four mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a debugger/programmer connector, and two 26-pin headers for interfacing with external electronics. Thanks to innovative manufacturing technology, it allows you to build

gadgets with unique functionalities and features quickly. Each part of the UNI Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the UNI Clicker programming method, using a third-party programmer or CODEGRIP/mikroProg connected to onboard JTAG/SWD header, the UNI Clicker board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Type-C (USB-C) connector, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or using a Li-Po/Li

Ion battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board (plus USB HOST/DEVICE), including the well-established mikroBUS™ socket, a standardized socket for the MCU card (SiBRAIN standard), and several user-configurable buttons and LED indicators. UNI Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

UNI clicker double image

Microcontroller Overview

MCU Card / MCU

default

Type

8th Generation

Architecture

ARM Cortex-M4

MCU Memory (KB)

256

Silicon Vendor

STMicroelectronics

Pin count

64

RAM (Bytes)

32768

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
CAN Polarity
PA1
PWM
NC
NC
INT
UART TX
PA9
TX
UART RX
PA10
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

CAN Isolator 3 Click Schematic schematic

Step by step

Project assembly

UNI Clicker front image hardware assembly

Start by selecting your development board and Click board™. Begin with the UNI Clicker as your development board.

UNI Clicker front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for STM32F745VG front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
UNI Clicker 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
Necto image step 7 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for CAN Isolator 3 Click driver.

Key functions:

  • canisolator3_generic_write - CAN Isolator 3 data writing function.

  • canisolator3_generic_read - CAN Isolator 3 data reading function.

  • canisolator3_set_pol_pin - CAN Isolator 3 set polarity function.

Open Source

Code example

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * @file main.c
 * @brief CAN Isolator 3 Click Example.
 *
 * # Description
 * This example writes and reads and processes data from CAN Isolator 3 Click.
 * The library also includes a function for selection of the output polarity.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration.
 *
 * ## Application Task
 * This example contains Transmitter/Receiver task depending on uncommented code.
 * Receiver logs each received byte to the UART for data logging,
 * while the transmitter sends messages every 2 seconds.
 *
 * ## Additional Function
 * - static err_t canisolator3_process ( canisolator3_t *ctx )
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "canisolator3.h"

#define PROCESS_BUFFER_SIZE 200
#define TX_MESSAGE "CAN Isolator 3 Click \r\n"

// Comment out the line below in order to switch the application mode to receiver.
#define DEMO_APP_TRANSMITTER

static canisolator3_t canisolator3;
static log_t logger;

static uint8_t app_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
static int32_t app_buf_len = 0;

/**
 * @brief CAN Isolator 3 data reading function.
 * @details This function reads data from device and concatenates data to application buffer. 
 * @param[in] ctx : Click context object.
 * See #canisolator3_t object definition for detailed explanation.
 * @return @li @c  0 - Read some data.
 *         @li @c -1 - Nothing is read.
 * See #err_t definition for detailed explanation.
 * @note None.
 */
static err_t canisolator3_process ( canisolator3_t *ctx );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    canisolator3_cfg_t canisolator3_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.
    canisolator3_cfg_setup( &canisolator3_cfg );
    CANISOLATOR3_MAP_MIKROBUS( canisolator3_cfg, MIKROBUS_1 );
    if ( UART_ERROR == canisolator3_init( &canisolator3, &canisolator3_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    canisolator3_default_cfg ( &canisolator3 );
    
#ifdef DEMO_APP_TRANSMITTER
    log_info( &logger, "---- Transmitter mode ----" );
#else
    log_info( &logger, "---- Receiver mode ----" );
#endif 
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_TRANSMITTER
    canisolator3_generic_write( &canisolator3, TX_MESSAGE, strlen( TX_MESSAGE ) );
    log_info( &logger, "---- Data sent ----" );
    Delay_ms( 2000 );
#else
    canisolator3_process( &canisolator3 );
#endif
}

int main ( void ) 
{
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

static err_t canisolator3_process ( canisolator3_t *ctx ) 
{
    uint32_t rx_size;
    char rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    rx_size = canisolator3_generic_read( &canisolator3, rx_buf, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 ) 
    {
        log_printf( &logger, "%s", rx_buf );
        return CANISOLATOR3_OK;
    }
    return CANISOLATOR3_ERROR;
}

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

Additional Support

Resources