Intermediate
30 min

Enable secure RS232 communication in industrial settings with ADM3252E and dsPIC33EP512MU810

Isolated transceiver for secure data transfer

RS232 Isolator Click with Explorer 16/32 development board

Published Oct 19, 2023

Click board™

RS232 Isolator Click

Dev. board

Explorer 16/32 development board

Compiler

NECTO Studio

MCU

dsPIC33EP512MU810

Your data's guardian, our fully isolated dual transceiver, is the ultimate bridge for secure UART to RS232 conversion, providing both security and reliability

A

A

Hardware Overview

How does it work?

RS232 Isolator Click is based on the ADM3252E, an integrated dual-channel RS232 driver/receiver, with the iCoupler® isolation technology from Analog Devices. This integrated circuit features four integrated galvanic isolation elements that provide the required isolation level. RS232 level inputs are inverted and encoded into waveforms that are used to energize the primary windings of the integrated transformers. At the secondary windings, the induced waveforms are decoded back into the digital values and routed to the pins, with the appropriate TTL/CMOS voltage levels. The same working principle is applied in the opposite direction, too. This way, the digital signals are

effectively conducted through the isolation barrier. Besides the UART RX and TX lines, the click also supports the hardware flow control via the CTS and RTS lines. One of the two existing channels is used for the UART data communication itself, while the other channel is used for the hardware flow control lines. The usage of the control lines is not always mandatory, so the lines can be disconnected from the mikroBUS if needed, by unsoldering the SMD jumpers labeled as J1 and J2. The ADM3252E IC also features the isoPower™ technology - an integrated DC-DC converter for generating all the required voltage levels, making it possible to power the Click board™ by 3.3V or 5V.

The operating voltage for the Click board™ can be set with the onboard SMD jumper. RS232 Isolator click features the onboard D-Sub 9 (DE9) connector for an easy and secure connection. 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.

RS232 Isolator Click top side image
RS232 Isolator Click bottom side image

Features overview

Development board

Explorer 16/32 development board is a flexible and convenient development, demonstration, and testing platform for 16-bit PIC24 MCUs, dsPIC® DSCs, and 32-bit PIC32 MCUs from Microchip Technology. It features all the necessary hardware to develop and debug a complete embedded application. The board accepts Processor Plug-In Modules (PIMs) designed for the Explorer 16 or Explorer 16/32 development board for easy device swapping. In addition to the hardware features provided by the board, hardware expansion is possible through the use of PICtail™ Plus

daughter cards and mikroBUS™ accessory boards. Coupled with the integrated PICkit™-On-Board (PKOB), MPLAB ICD In-Circuit Debugger real-time debug facilities enable faster evaluation and prototyping of applications. This development board supports all the Explorer PIMs. However, not all PIMs are supported by the PKOB. To check the list of supported and unsupported PIMs, refer to the PICkit™ On-Board 3 (PKOB3) Support List. For PIMs not on the PKOB3 support list, use the JP1 or J14 connectors to program the device with a newer generation programming tool. Explorer 16/32

development board offers only the main board, allowing customization of the other necessary components. Choose your PIM based on MCUs and DSCs under consideration from a wide range of Processor Plug-In Modules. This board is optimal for customers migrating from Classic Explorer 16 to the new Explorer 16/32 platform, while all the necessary additional components like Processor Plug-In Modules and PICtail™ Plus Daughter Boards are already available.

Explorer 16/32 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

dsPIC

MCU Memory (KB)

512

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

53248

You complete me!

Accessories

DB9 Cable Female-to-Female (2m) cable is essential for establishing dependable serial data connections between devices. With its DB9 female connectors on both ends, this cable enables a seamless link between various equipment, such as computers, routers, switches, and other serial devices. Measuring 2 meters in length, it offers flexibility in arranging your setup without compromising data transmission quality. Crafted with precision, this cable ensures consistent and reliable data exchange, making it suitable for industrial applications, office environments, and home setups. Whether configuring networking equipment, accessing console ports, or utilizing serial peripherals, this cable's durable construction and robust connectors guarantee a stable connection. Simplify your data communication needs with the 2m DB9 female-to-female cable, an efficient solution designed to meet your serial connectivity requirements easily and efficiently.

RS232 Isolator Click accessories image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
UART CTS
PG9
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
UART RTS
PA15
INT
UART TX
PF3
TX
UART RX
PF2
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

RS232 Isolator Click Schematic schematic

Step by step

Project assembly

Explorer 16/32 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Explorer 16/32 development board as your development board.

Explorer 16/32 front image hardware assembly
GNSS2 Click front image hardware assembly
PIM for PIC32MZ2048EFH100 front image hardware assembly
Prog-cut hardware assembly
GNSS2 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
Explorer 16/32 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 RS232 Isolator Click driver.

Key functions:

  • rs232_2_set_rts - Function settings RTS state

  • rs232_2_get_cts - Read CTS state

  • rs232isolator_send_command - Function for send command

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 Rs232Isolator Click example
 * 
 * # Description
 * This example reads and processes data from RS232 Isolator Clicks.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes driver.
 * 
 * ## Application Task  
 * Reads the received data.
 * 
 * ## Additional Function
 * - rs232isolator_process ( ) - The general process of collecting presponce 
 *                                   that sends a module.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rs232isolator.h"
#include "string.h"

#define PROCESS_COUNTER 10
#define PROCESS_RX_BUFFER_SIZE 500
#define PROCESS_PARSER_BUFFER_SIZE 500

#define TEXT_TO_SEND  "MikroE\r\n"

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

#define DEMO_APP_RECEIVER
//#define DEMO_APP_TRANSMITER

static rs232isolator_t rs232isolator;
static log_t logger;

static char current_rsp_buf[ PROCESS_PARSER_BUFFER_SIZE ];
static uint8_t send_data_cnt = 0; 
// ------------------------------------------------------- ADDITIONAL FUNCTIONS

static void rs232isolator_process ( void )
{
    int16_t rsp_size;
    uint16_t rsp_cnt = 0;
    
    char uart_rx_buffer[ PROCESS_RX_BUFFER_SIZE ] = { 0 };
    uint8_t check_buf_cnt;
    uint8_t process_cnt = PROCESS_COUNTER;
    
    // Clear parser buffer
    memset( current_rsp_buf, 0 , PROCESS_PARSER_BUFFER_SIZE ); 
    
    while( process_cnt != 0 )
    {
        rsp_size = rs232isolator_generic_read( &rs232isolator, &uart_rx_buffer, PROCESS_RX_BUFFER_SIZE );

        if ( rsp_size > 0 )
        {  
            // Validation of the received data
            for ( check_buf_cnt = 0; check_buf_cnt < rsp_size; check_buf_cnt++ )
            {
                if ( uart_rx_buffer[ check_buf_cnt ] == 0 ) 
                {
                    uart_rx_buffer[ check_buf_cnt ] = 13;
                }
            }
            
            log_printf( &logger, "%s\r\n", uart_rx_buffer );
            
            // Storages data in parser buffer
            rsp_cnt += rsp_size;
            if ( rsp_cnt < PROCESS_PARSER_BUFFER_SIZE )
            {
                strncat( current_rsp_buf, uart_rx_buffer, rsp_size );
            }
            
            // Clear RX buffer
            memset( uart_rx_buffer, 0, PROCESS_RX_BUFFER_SIZE );
        } 
        else 
        {
            process_cnt--;
            
            // Process delay 
            Delay_ms ( 100 );
        }
    }
    log_printf( &logger, "%s\r\n", current_rsp_buf );
}

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    rs232isolator_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.

    rs232isolator_cfg_setup( &cfg );
    RS232ISOLATOR_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    rs232isolator_init( &rs232isolator, &cfg );
}

void application_task ( void )
{
#ifdef DEMO_APP_RECEIVER
    rs232isolator_process( );
#endif
    
#ifdef DEMO_APP_TRANSMITER
    rs232isolator_process( );
    
    if ( send_data_cnt == 5 )
    {
        rs232isolator_send_command( &rs232isolator, TEXT_TO_SEND );
        send_data_cnt = 0;
    }
    else
    {
        send_data_cnt++;
    }

#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

Love this project?

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