Beginner
10 min

Safeguard your RS485 data with ADM2682E and PIC18F2455

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

RS485 Isolator Click with EasyPIC v8

Published Nov 01, 2023

Click board™

RS485 Isolator Click

Dev Board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18F2455

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

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

default

Architecture

PIC

MCU Memory (KB)

24

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Receiver Enable
RA0
RST
Driver Enable
RA5
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
RC6
TX
UART RX
RC7
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
2

Take a closer look

Schematic

RS485 Isolator 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
LTE IoT 5 Click front image hardware assembly
MCU DIP 28 hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
EasyPIC v8 28pin-DIP Access - 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 via UART Mode

1. Once the code example is loaded, pressing the "FLASH" button initiates the build process, and programs it on the created setup.

2. After the programming is completed, click on the Tools icon in the upper-right panel, and select the UART Terminal.

3. After opening the UART Terminal tab, first check the baud rate setting in the Options menu (default is 115200). If this parameter is correct, activate the terminal by clicking the "CONNECT" button.

4. Now terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART_Application_Output

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

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

/*!
 * \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

Love this project?

'Buy This Kit' button takes you directly to the shopping cart where you can easily add or remove products.