Experience peace of mind as you securely isolate I2C communication using CPC5902 and PIC32MZ1024EFH064
I2C data's Fort Knox: Secure isolation, seamless communication!
Published Sep 03, 2023
Click board™
I2C Isolator 3 Click
Dev. board
PIC32MZ clicker
Compiler
NECTO Studio
MCU
PIC32MZ1024EFH064
Our I2C communication isolator solution shields your data from interference and noise, ensuring secure and reliable communication in sensitive applications
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Hardware Overview
How does it work?
I2C Isolator 3 Click is based on the CPC5902, a dual optically isolated bidirectional logic-bus repeater from IXYS Integrated Circuits Division. It bidirectionally buffers the two I2C signals across the isolation barrier and supports I2C clock stretching while providing 3750Vrms of galvanic isolation. The buffered signals will always return to their proper value after a transient interruption on either side. Unlike competitive magnetically isolated digital isolators, transformers, or capacitive isolators, the CPC5902 doesn’t need to be clocked periodically to sustain the logic states. Besides, it offers glitch-free operation, excellent reliability, and a very long operational life. If different supply voltage levels are used at each power supply side, it can also function as a logic
level translator for levels as low as 2.7V or as high as 5.5V. This optically coupled I2C bus repeater is ideal for Power-over-Ethernet (PoE) applications, buffering and isolating the clock and data signals between the host controller and the Power Supply Equipment (PSE) controller. Additional applications include a power supply high-side interface, an I2C bus length extender, and isolated signal monitoring and control. An extensive operational power supply range of 2.7V to 5.5V enables I2C logic-level translation applications. I2C Isolator 3 Click communicates with MCU using the standard I2C 2-Wire interface and supports both Standard and Fast Mode with a transfer rate of up to 400kbps. The CPC5902 is also fully compatible with any single or double-wire bus in the
frequency range from 0 Hz to 500 kHz, corresponding to a 400 kbps transfer rate for the I2C bus. It also possesses two terminals labeled as VIN and I2C at the bottom of the Click board™, where VIN represents the B-side power supply of the repeater, while the other I2C corresponds to the isolated bidirectional logic-bus terminal. 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.
Features overview
Development board
PIC32MZ Clicker is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit PIC32MZ microcontroller with FPU from Microchip, a USB connector, LED indicators, buttons, a mikroProg connector, and a header for interfacing with external electronics. Thanks to its compact design with clear and easy-recognizable silkscreen markings, it provides a fluid and immersive working experience, allowing access anywhere and under
any circumstances. Each part of the PIC32MZ Clicker development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the PIC32MZ Clicker programming method, using USB HID mikroBootloader, or through an external mikroProg connector for PIC, dsPIC, or PIC32 programmer, the Clicker board also includes a clean and regulated power supply module for the development kit. The USB Micro-B connection can provide up to 500mA of current, which is more than enough to operate all onboard
and additional modules. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several buttons and LED indicators. PIC32MZ Clicker is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.
Microcontroller Overview
MCU Card / MCU
Architecture
PIC32
MCU Memory (KB)
1024
Silicon Vendor
Microchip
Pin count
64
RAM (Bytes)
524288
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the PIC32MZ clicker as your development board.
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 I2C Isolator 3 Click driver.
Key functions:
i2cisolator3_send_cmd- This function sends the desired command to a remote device wired with CPC5902i2cisolator3_write_byte- This function writes the byte of data to the targeted 8-bit register address of the remote device wired with CPC5902i2cisolator3_read_byte- This function read a the byte of data from the targeted 8-bit register address of the remote device wired with CPC5902
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 main.c
* @brief I2CIsolator3 Click example
*
* # Description
* This is an example that demonstrates the use of the I2C Isolator 3 click board. In this example, we measure temperature
* from the Thermo 20 click connected to the I2C Isolator 3 click board.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initializes I2C and start to write log. Initialization driver enables - I2C,
* set I2C slave address of the Thermo 20 click, performs software reset, also write log.
*
* ## Application Task
* In this example via Thermo 20 click we get the data processed by the function. When the function processes the data, we get
* the temperature information. All data logs write on USB UART changes every 3 sec.
*
* Additional Functions :
* - void calculate_temperature( ) - Calculate temperature in degrees Celsius.
*
* @author Jelena Milosavljevic
*
*/
#include "board.h"
#include "log.h"
#include "i2cisolator3.h"
static i2cisolator3_t i2cisolator3;
static log_t logger;
static float temperature;
static char log_text[ 50 ];
void calculate_temperature ( ) {
uint16_t res_adc;
uint8_t rx_buf[ 3 ];
i2cisolator3_burst_read ( &i2cisolator3, I2CISOLATOR3_THERMO20_CMD_READ_ADC, rx_buf, 3 );
res_adc = rx_buf[ 0 ];
res_adc <<= 8;
res_adc |= rx_buf[ 1 ];
temperature = ( float ) res_adc;
temperature /= 65535.0;
temperature *= 165.0;
temperature -= 40.0;
}
void application_init ( void ) {
log_cfg_t log_cfg; /**< Logger config object. */
i2cisolator3_cfg_t i2cisolator3_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.
i2cisolator3_cfg_setup( &i2cisolator3_cfg );
I2CISOLATOR3_MAP_MIKROBUS( i2cisolator3_cfg, MIKROBUS_1 );
err_t init_flag = i2cisolator3_init( &i2cisolator3, &i2cisolator3_cfg );
if ( I2C_MASTER_ERROR == init_flag ) {
log_error( &logger, " Application Init Error. " );
log_info( &logger, " Please, run program again... " );
for ( ; ; );
}
log_printf( &logger, " Driver Init. Done \r\n" );
log_printf( &logger, " Set I2C Slave Address \r\n" );
log_printf( &logger, " of the Thermo 20 click \r\n" );
Delay_ms( 100 );
log_printf( &logger, "--------------------------\r\n" );
log_printf( &logger, " Software Reset \r\n" );
i2cisolator3_send_cmd( &i2cisolator3, I2CISOLATOR3_THERMO20_CMD_RESET );
Delay_ms( 100 );
log_printf( &logger, "--------------------------\r\n" );
log_printf( &logger, " Start Measuring \r\n" );
log_printf( &logger, "--------------------------\r\n" );
Delay_ms( 100 );
log_info( &logger, " Application Task \r\n" );
}
void application_task ( void ) {
i2cisolator3_send_cmd( &i2cisolator3, I2CISOLATOR3_THERMO20_CMD_CONVERSION );
Delay_ms( 100 );
calculate_temperature( );
log_printf( &logger, "Temperature : %.2f \r\n", temperature );
Delay_ms( 3000 );
}
void main ( void ) {
application_init( );
for ( ; ; ) {
application_task( );
}
}
// ------------------------------------------------------------------------ END
