Intermediate
30 min
0

Extend your network beyond boundaries with ADM2763E and PIC32MZ1024EFF144

The power of full isolation: Redefining RS485 communication

RS485 Isolator 3 Click with UNI Clicker

Published Oct 20, 2023

Click board™

RS485 Isolator 3 Click

Development board

UNI Clicker

Compiler

NECTO Studio

MCU

PIC32MZ1024EFF144

Unleash the potential of your RS485 network with complete isolation, transforming the way you communicate and ensuring data integrity like never before

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Hardware Overview

How does it work?

RS485 Isolator 3 Click is based on the ADM2763E, a 5.7kV RMS signal isolated RS-485 transceiver from Analog Devices. The ADM2763E is optimized for low speed over long cable runs and has a maximum data rate of 500kbps. It is protected against ≥±12 kV contact and ≥±15 kV air IEC 61000-4-2 electrostatic discharge (ESD) events on the RS485 receiver and driver terminal pins, easily accessible via the screw terminal blocks. The ADM2763E has four bus signals: signal A for the noninverting input signal, signal B for the inverting input signal, signal Y for the noninverting output signal, and signal Z for the inverting output signal, alongside a common ground connection. Using coplanar transformer coils with an ON or OFF keying modulation scheme allows a high data throughput across the isolation barrier of the ADM2763E while minimizing radiation emissions. Architecture like this provides a digital isolator immunity to common-mode transients >250 kV/μs

across the device's full temperature and supply range. The ADM2763E also features a proprietary transmitter architecture with a low driver output impedance that increases the differential output voltage. The high differential output voltage extends the reach of the ADM2763E to longer cable lengths and makes this board suitable for PROFIBUS® nodes when powered with 5V on the isolated side of a supply (isolated-side provides the possibility of a supply voltage in the range from 3V to 5.5V). Besides commonly used UART TX and RX pins on the mikroBUS™ socket, this board also has receiver and driver enable pins routed to the RE and DE pins of the mikroBUS™ socket. It also features a receiver cable invert pin, routed to the INV pin of the mikroBUS™ socket, to quickly correct the reversed cable connection on the A and B receiver bus pins while maintaining complete receiver fail-safe performance. In addition, the ADM2763E has a built-in receiver

fail-safe for the bus Idle condition, accessible through some of the unpopulated onboard jumpers (the R4 and R5 pull-up resistors to the VDD2 isolated-side supply on the ADM2763E pins A and Y, as well as the R14 and R15 pull-down resistors to the GND2 common ground connection on pins B and Z). These resistors can be fitted if the user connects this board to other devices that require external biasing resistors on the bus. The ADM2763E also has a jumper that allows adding a 120Ω load to the RS485 receiver by placing the jumper cap on it. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VDD1 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.

RS485 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

PIC32

MCU Memory (KB)

1024

Silicon Vendor

Microchip

Pin count

144

RAM (Bytes)

262144

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Receiver Enable
PH2
RST
ID COMM
PH3
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
Driver Enable
PB8
PWM
Receiver Cable Invert
PD0
INT
UART TX
PB14
TX
UART RX
PB15
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

RS485 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 RS485 Isolator 3 Click driver.

Key functions:

  • rs485isolator3_enable_receiver_input - RS485 Isolator 3 enable receiver input function

  • rs485isolator3_disable_receiver_input - RS485 Isolator 3 disable receiver input function

  • rs485isolator3_disable_output - RS485 Isolator 3 disable output 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 RS485 Isolator 3 Click Example.
 *
 * # Description
 * This example reads and processes data from RS485 Isolator 3 clicks.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and enables the selected mode.
 *
 * ## Application Task
 * Depending on the selected mode, it reads all the received data or sends the desired message
 * every 2 seconds.
 * 
 * ## Additional Function
 * - static err_t rs485isolator3_process ( void )
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "rs485isolator3.h"

#define PROCESS_BUFFER_SIZE 200

#define DEMO_APP_RECEIVER
// #define DEMO_APP_TRANSMITTER

static rs485isolator3_t rs485isolator3;
static log_t logger;

uint8_t data_buf[ 8 ] = { 'M', 'i', 'k', 'r', 'o', 'E', '\r', '\n' };

/**
 * @brief RS485 Isolator 3 data reading function.
 * @details This function reads data from device and concatenates data to application buffer.
 * @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 rs485isolator3_process ( void );

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rs485isolator3_cfg_t rs485isolator3_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.
    rs485isolator3_cfg_setup( &rs485isolator3_cfg );
    RS485ISOLATOR3_MAP_MIKROBUS( rs485isolator3_cfg, MIKROBUS_1 );
    if ( UART_ERROR == rs485isolator3_init( &rs485isolator3, &rs485isolator3_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    rs485isolator3_default_cfg ( &rs485isolator3 );
    
#ifdef DEMO_APP_RECEIVER
    rs485isolator3_enable_receiver_input( &rs485isolator3 );
    rs485isolator3_disable_output( &rs485isolator3 );
    log_info( &logger, "---- Receiver mode ----" );
#endif 
#ifdef DEMO_APP_TRANSMITTER
    rs485isolator3_disable_receiver_input( &rs485isolator3 );
    rs485isolator3_enable_output( &rs485isolator3 );    
    log_info( &logger, "---- Transmitter mode ----" );
#endif
    
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_RECEIVER
    rs485isolator3_process( );
#endif    
    
#ifdef DEMO_APP_TRANSMITTER
    rs485isolator3_generic_write( &rs485isolator3, data_buf, strlen( data_buf ) );
    log_info( &logger, "---- Data sent ----" );
    Delay_ms( 2000 );
#endif    
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

static err_t rs485isolator3_process ( void ) 
{
    int32_t rx_size;
    char rx_buf[ PROCESS_BUFFER_SIZE ] = { 0 };
    rx_size = rs485isolator3_generic_read( &rs485isolator3, rx_buf, PROCESS_BUFFER_SIZE );
    if ( rx_size > 0 ) 
    {
        log_printf( &logger, "%s", rx_buf );
        return RS485ISOLATOR3_OK;
    }
    return RS485ISOLATOR3_ERROR;
}

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

Additional Support

Resources