Intermediate
30 min
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Simplify your data exchange and empower data transformation using ZDU0110RFX and PIC18LF4685

Enhance data flow: The RS232 to I2C conversion you need

RS232 to I2C Click with EasyPIC v7

Published Nov 01, 2023

Click board™

RS232 to I2C Click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18LF4685

Discover the magic of our RS232 to I2C converter, enabling efficient data transformation and modernizing your communication

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Hardware Overview

How does it work?

RS232 to I2C Click is based on the ZDU0110RFX, a digital UART interface IC designed to give you an I2C-controlled UART interface from Zilog. The ZDU0110RFX provides full-duplex asynchronous communications with a 128B FIFO (First In, First Out) buffer, allocating 64 bytes each to the receive and transmit operations. This interface bridge simultaneously represents the connection between the MCU and the RS232 line driver and receiver, the MAX3232, which completes this solution by making it a complete RS232 to I2C converter. The MAX3222 is a low-power and high-speed up to 1Mbps RS232 transceiver. It runs at data rates of 120kbps while maintaining RS-232 output levels. This transceiver is connected to the DB9 Female Connector, compliant with TIA/EIA-232-F standards, which provides the users with an electrical interface between an asynchronous communication controller and the serial-port connector. Alongside RS232 TX and RX signals, the DB-9 connector also carries flow control signals (CTS and RTS) for maximum reliability. RS232 to I2C Click communicates with MCU using the

standard I2C 2-Wire interface that supports Standard-Mode (100 kHz) and Fast-Mode (400 kHz) operations. Besides, the ZDU0110RFX allows choosing its I2C slave address using the onboard SMD jumpers labeled ADDR SEL. The selection can be made by positioning the SMD jumper to an appropriate position marked as 0 or 1. This fully programmable UART IC is preconfigured to operate at a 57.6kb/s rate, so configuration is not required to access the UART or the EEPROM. The ZDU0110RFX also contains a 4kbit EEPROM and General Purpose Input and Output (GPIO) with programmable interrupt capability. The EEPROM is accessible via I2C communication and comes with the configurable Write Protection function labeled as WP routed on the CS pin of the mikroBUS™ socket and an active-low reset signal routed on the RST pin of the mikroBUS™ socket. The WP pin protects the EEPROM memory from write operations and must be set to a high logic state to inhibit all the write operations. Also, the ZDU0110RFX provides separate programmable interrupts and interrupt lines for UART and GPIO

notifications. These interruptions mean the controlling device doesn't have to poll the UART IC for data. The interrupt selection can be made by positioning SMD jumpers labeled as INT SEL to an appropriate position marked as UART or GPIO and processed by the INT pin of the mikroBUS™ socket. In addition to UART communication pins from the mikroBUS™ socket, the user can connect the TX/RX signals directly through the UART external connection header on the left side of the board, while previously mentioned GPIO pins can be connected to the General Purpose I/O header on the right side of the board. The two pins on this header, GP0 and GP1, are GPIO pins with an interrupt function. 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 to I2C Click top side image
RS232 to I2C Click bottom side image

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. 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, EasyPIC v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC 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 various external power sources, including an external 12V power supply, 7-23V AC or 9-32V 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. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC 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.

EasyPIC v7 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

96

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3328

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 to I2C Click accessories image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RE1
RST
EEPROM Write Protect
RE0
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RB0
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Schematic

RS232 to I2C Click Schematic schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

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

EasyPIC v7 front image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
EasyPIC v7 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 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

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

UART Application Output Step 1

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

UART Application Output Step 2

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

UART Application Output Step 3

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART Application Output Step 4

Software Support

Library Description

This library contains API for RS232 to I2C Click driver.

Key functions:

  • rs232toi2c_write_tx_fifo - This function writes a desired number of data bytes to the TX fifo.

  • rs232toi2c_read_rx_fifo - This function reads all data from RX fifo.

  • rs232toi2c_get_int_pin - This function returns the INT pin logic state.

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 RS232toI2C Click example
 *
 * # Description
 * This example demonstrates the use of an RS232 to I2C click board by showing
 * the communication between the two click board configured as a receiver and transmitter.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets
 * the default UART configuration with 9600 baud rate.
 *
 * ## Application Task
 * Depending on the selected mode, it reads all the received data and sends an adequate response back or 
 * sends the desired message and waits for a response every 2 seconds.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "rs232toi2c.h"

static rs232toi2c_t rs232toi2c;
static log_t logger;

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

#define DEMO_TEXT_MESSAGE           "MikroE - RS232 to I2C click"
#define RESPONSE_OK                 "OK"
#define RESPONSE_ERROR              "ERROR"

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    rs232toi2c_cfg_t rs232toi2c_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.
    rs232toi2c_cfg_setup( &rs232toi2c_cfg );
    RS232TOI2C_MAP_MIKROBUS( rs232toi2c_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == rs232toi2c_init( &rs232toi2c, &rs232toi2c_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( RS232TOI2C_ERROR == rs232toi2c_default_cfg ( &rs232toi2c ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    uint32_t system_version;
    if ( RS232TOI2C_OK == rs232toi2c_read_system_version ( &rs232toi2c, &system_version ) )
    {
        log_printf ( &logger, " System Version: 0x%.6LX\r\n", system_version );
    }
#ifdef DEMO_APP_TRANSMITTER
    log_printf( &logger, " Application Mode: Transmitter\r\n" );
#else
    log_printf( &logger, " Application Mode: Receiver\r\n" );
#endif
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
#ifdef DEMO_APP_TRANSMITTER
    if ( RS232TOI2C_OK == rs232toi2c_write_tx_fifo( &rs232toi2c, DEMO_TEXT_MESSAGE, strlen( DEMO_TEXT_MESSAGE ) ) )
    {
        log_printf( &logger, " The message \"%s\" has been sent!\r\n", ( char * ) DEMO_TEXT_MESSAGE );
        uint16_t timeout_cnt = 5000;
        // wait for an RX interrupt
        while ( rs232toi2c_get_int_pin ( &rs232toi2c ) && timeout_cnt )
        {
            Delay_ms ( 1 );
            timeout_cnt--;
        }
        if ( timeout_cnt )
        {
            uint8_t data_buf[ 256 ] = { 0 };
            uint8_t data_len = 0;
            if ( RS232TOI2C_OK == rs232toi2c_read_rx_fifo( &rs232toi2c, data_buf, &data_len ) )
            {
                log_printf( &logger, " Response: " );
                for ( uint8_t cnt = 0; cnt < data_len; cnt++ )
                {
                    log_printf( &logger, "%c", data_buf[ cnt ] );
                }
            }
        }
        else
        {
            log_error ( &logger, "TIMEOUT - no response received" );
        }
        log_printf( &logger, "\r\n\n" );
        Delay_ms( 2000 );
    }
#else
    // wait for an RX interrupt
    while ( rs232toi2c_get_int_pin ( &rs232toi2c ) );
    
    uint8_t data_buf[ 256 ] = { 0 };
    uint8_t data_len = 0;
    if ( RS232TOI2C_OK == rs232toi2c_read_rx_fifo( &rs232toi2c, data_buf, &data_len ) )
    {
        log_printf( &logger, " A new message has received: \"" );
        for ( uint8_t cnt = 0; cnt < data_len; cnt++ )
        {
            log_printf( &logger, "%c", data_buf[ cnt ] );
        }
        log_printf( &logger, "\"\r\n" );
        if ( strstr ( data_buf, DEMO_TEXT_MESSAGE ) )
        {
            if ( RS232TOI2C_OK == rs232toi2c_write_tx_fifo( &rs232toi2c, RESPONSE_OK, strlen( RESPONSE_OK ) ) )
            {
                log_printf( &logger, " Response \"%s\" has been sent to the sender!\r\n\n", ( char * ) RESPONSE_OK );
            }
        }
        else
        {
            if ( RS232TOI2C_OK == rs232toi2c_write_tx_fifo( &rs232toi2c, RESPONSE_ERROR, strlen( RESPONSE_ERROR ) ) )
            {
                log_printf( &logger, " Response \"%s\" has been sent to the sender!\r\n\n", ( char * ) RESPONSE_ERROR );
            }
        }
    }
#endif
}

void main ( void ) 
{
    application_init( );

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

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

Additional Support

Resources