Beginner
10 min

Safeguard your RS485 data with ADM2682E and ATmega328P

Isolate, elevate, communicate: Unleash the power of RS485!

RS485 Isolator Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

RS485 Isolator Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Our RS485 signal isolator empowers your communication network by providing robust isolation, ensuring reliable data transmission in industrial environments

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Hardware Overview

How does it work?

RS485 Isolator Click is based on the ADM2682E, a signal, and a power-isolated RS-485 transceiver with ESD protection from Analog Devices. The signal isolation is implemented on the logic side of the interface, which is achieved by having a digital isolation section and a transceiver section. The applied data to the RX and DE pins are referenced to a logic ground and coupled across an isolated barrier to appear at the transceiver section referenced to the isolated ground. Similarly, the single-ended receiver output signal, referenced to

isolated ground in the transceiver section, is coupled across the isolation barrier to appear at the RX pin referenced to logic ground. RS485 Isolator Click uses a standard 2-Wire UART interface to communicate with the host MCU. There is driver enable input DE, which enables the driver with logic HIGH. The receiver-enable input RE enables the receiver with a LOW logic state. There is also a TERM jumper, which adds a 120R termination resistor at the receiver side of the bus, which minimizes the reflections. The input/output

terminal is properly labeled A and B for receiver input and Z and Y for driver output. 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.

RS485 Isolator Click top side image
RS485 Isolator Click bottom side image

Features overview

Development board

Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an

ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the

first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.

Arduino UNO Rev3 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

You complete me!

Accessories

Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Arduino UNO accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Receiver Enable
PD2
RST
Driver Enable
PB2
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
UART TX
PD0
TX
UART RX
PD1
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

RS485 Isolator Click Schematic schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Click Shield for Arduino UNO front image hardware assembly
Arduino UNO Rev3 front image hardware assembly
Charger 27 Click front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Board mapper by product8 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
Arduino UNO MCU 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 RS485 Isolator Click driver.

Key functions:

  • rs485isolator_set_receiver_mode - Set receiver state.

  • rs485isolator_generic_read - Generic read function.

  • rs485isolator_generic_write - Generic write function.

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 
 * \brief RS485 Isolator Click example
 * 
 * # Description
 * This example reads and processes data from RS485 Isolator Clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver.
 * 
 * ## Application Task  
 * Depending on the selected mode, it reads all the received data or sends the desired message
 * every 2 seconds.
 * 
 * ## Additional Function
 * - rs485isolator_process ( ) - The general process of collecting the received data.
 * 
 * @note
 * Wire connection guide : Driver(Master)       Slave
 *                                     Y   ->   A
 *                                     Z   ->   B
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rs485isolator.h"
#include "string.h"

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

#define TEXT_TO_SEND "MIKROE - RS485 Isolator Click\r\n"

#define PROCESS_RX_BUFFER_SIZE 100

// ------------------------------------------------------------------ VARIABLES

static rs485isolator_t rs485isolator;
static log_t logger;

// ------------------------------------------------------- ADDITIONAL FUNCTIONS

static void rs485isolator_process ( void )
{
    uint8_t uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
    
    int32_t rsp_size = rs485isolator_generic_read( &rs485isolator, uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );

    if ( rsp_size > 0 )
    {  
        log_printf( &logger, "Received data: " );
        
        for ( uint8_t check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ )
        {
            log_printf( &logger, "%c", uart_rx_buffer[ check_buf_cnt ] );
        }
        Delay_ms ( 100 );
        rsp_size = rs485isolator_generic_read( &rs485isolator, uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );
        if ( rsp_size > 0 )
        { 
            for ( uint8_t check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ )
            {
                log_printf( &logger, "%c", uart_rx_buffer[ check_buf_cnt ] );
            }
        }
    }
    Delay_ms ( 100 );
}

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    rs485isolator_cfg_t cfg;

    /** 
     * 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.
    rs485isolator_cfg_setup( &cfg );
    RS485ISOLATOR_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rs485isolator_init( &rs485isolator, &cfg );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
#ifdef DEMO_APP_TRANSMITTER
    rs485isolator_generic_write( &rs485isolator, TEXT_TO_SEND, strlen ( TEXT_TO_SEND ) );
    log_info( &logger, "---- Data sent ----" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
#else
    rs485isolator_process( );
#endif    
}

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;
}

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

Additional Support

Resources

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