Beginner
10 min

Safeguard your RS485 data with ADM2682E and ATmega1284

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

RS485 Isolator Click with EasyAVR v7

Published Nov 07, 2023

Click board™

RS485 Isolator Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega1284

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

A

A

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

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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.

EasyAVR v7 horizontal image

Microcontroller Overview

MCU Card / MCU

ATmega1284

Architecture

AVR

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Receiver Enable
PA6
RST
Driver Enable
PA5
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
PD1
TX
UART RX
PD0
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

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

EasyAVR v7 front image hardware assembly
GNSS2 Click front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyAVR v7 Access DIP 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 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
EasyPIC PRO v7a Display Selection Necto Step 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

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( 2000 );
#else
    rs485isolator_process( );
#endif    
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources

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