Intermediate
30 min

Unlock the potential of extended I2C communication with LTC4331 and PIC32MZ2048EFM100

Reliable I2C over long distances

I2C Extend Click with Curiosity PIC32 MZ EF

Published Sep 12, 2023

Click board™

I2C Extend Click

Dev. board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Achieve reliable I2C communication over long distances, ensuring your data reaches its destination intact and on time

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Hardware Overview

How does it work?

I2C Extend Click is based on the LTC4331, a point-to-point compatible I2C peripheral device extender designed for operation in high-noise industrial environments. Using a ±60V fault-protected differential transceiver, the LTC4331 can extend an I2C/SMBus bus, including a remote interrupt function and a control signal, over a single twisted pair differential link. Thanks to selectable link baud rates, the I2C bus can be extended up to 1200m, depending on the link speed and external factors such as environmental noise level, humidity, cable quality, and more. Standard twisted-pair cables with RJ45 connectors can be used, the same as in the ethernet devices, and more. Besides the I2C protocol extension, the I2C Extend click also supports local remote control and interrupt functions. Local to remote control ensures that the values set on the local side CTRL pin propagate to the remote side CTRL pin over

the differential link. Users can choose a pin on the mikroBUS™ socket used for that purpose (CS or RST) using the onboard jumper named PIN SEL. The interrupt pin acts as an open-drain output in local mode and an input in remote mode. An interrupt signal on the INT pin in the I2C Extend Click is mirrored from the remote to the local network using the differential link. On the remote side, INT is an input pin that can be connected to remote I2C peripheral devices, while on the local side, it operates as an open-drain output that can be connected to a shared local interrupt line. Because of the dual functionality of the I2C Extend Click, the user needs to set the mode of operation of the Click board™. That is easily achieved using the onboard MODE switch, with two positions: local mode (LCL), where this Click board™ is in I2C slave mode, and remote mode (RMT), where this Click board™ is in I2C master mode. Besides mode

selection, I2C Extend Click can also link speed and I2C address selection jumpers onboard, named SPEED SEL and ADDR SEL, respectively. This Click board™ has Link status (LINK) and ready status (RDY) LEDs, making troubleshooting easy. The LINK LED activates in remote mode when the device establishes link communication. In local mode, the LINK LED is active after the LTC4331’s I2C interface has joined the I2C bus and establishes link communication. The RDY LED is active after the device’s I2C interface has joined the bus. 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.

I2C Extend Click hardware overview image

Features overview

Development board

Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand

functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,

which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.

Curiosity PIC32MZ EF double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Control Pin
RA9
RST
Control Pin
RPD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
NC
NC
GND
NC
NC
PWM
Interrupt
RF13
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RPA14
SCL
I2C Data
RPA15
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

I2C Extend Click Schematic schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

Curiosity PIC32MZ EF front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Curiosity PIC32 MZ EF MB 1 Access - upright/background 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
Curiosity PIC32 MZ EF 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 I2C Extend Click driver.

Key functions:

  • i2cextend_rmt_multi_read - Generic multi read data in Remote Mode function

  • i2cextend_set_config - Set the configuration function

  • i2cextend_set_out_slave_address - Set out slave address 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 main.c
 * @brief I2CExtend Click example
 *
 * # Description
 * This is an example which demonstrates the use of I2C Extend Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization driver enables - I2C, 
 * check communication with device 6DOF IMU 11 Click 
 * connected to the I2C Extend Click ( Remote Mode ),
 * set default configuration and start measurement.
 *
 * ## Application Task
 * In this example, we read Accel and Mag axis of the connected 
 * 6DOF IMU 11 Click boards to the I2C Extend Click ( Remote Mode )
 * which is connected by a LAN cable to I2C Extend Click ( Local Mode ).
 * Results are being sent to the Usart Terminal where you can track their changes.
 * All data logs write on USB uart changes for every 2 sec.
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "i2cextend.h"

static i2cextend_t i2cextend;
static log_t logger;
int16_t axis;

void i2cextend_6dofimu11_get_axis ( i2cextend_t *ctx, uint8_t axis_out_reg ) {
    uint16_t rx_val;
    uint8_t rx_buf[ 2 ];
    
    i2cextend_rmt_multi_read( ctx, C6DOFIMU11_I2C_SLAVE_ADDRESS_GND, axis_out_reg, &rx_buf[ 0 ], 2 );

    rx_val = rx_buf[ 1 ];
    rx_val <<= 8;
    rx_val |= rx_buf[ 0 ];

    axis = ( int16_t ) rx_val;
}

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    i2cextend_cfg_t i2cextend_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.
    i2cextend_cfg_setup( &i2cextend_cfg );
    I2CEXTEND_MAP_MIKROBUS( i2cextend_cfg, MIKROBUS_1 );
    err_t init_flag = i2cextend_init( &i2cextend, &i2cextend_cfg );
    if ( I2C_MASTER_ERROR == init_flag ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
    
    if ( i2cextend_rmt_read( &i2cextend, C6DOFIMU11_I2C_SLAVE_ADDRESS_GND, C6DOFIMU11_REG_WHO_AM_I ) == C6DOFIMU11_WHO_AM_I_WIA_ID ) {
        log_printf( &logger, "        SUCCESS         \r\n" );
        log_printf( &logger, "------------------------\r\n" );
    } else {
        log_printf( &logger, "         ERROR          \r\n" );
        log_printf( &logger, "    Reset the device    \r\n" );
        log_printf( &logger, "------------------------\r\n" );
        for ( ; ; );
    }
    i2cextend_rmt_write( &i2cextend, C6DOFIMU11_I2C_SLAVE_ADDRESS_GND, C6DOFIMU11_REG_CNTL2, C6DOFIMU11_CNTL2_TEMP_EN_STANDBY_MODE |
                                                                                  C6DOFIMU11_CNTL2_MAG_EN_STANDBY_MODE |
                                                                                  C6DOFIMU11_CNTL2_ACCEL_EN_STANDBY_MODE );

    i2cextend_rmt_write ( &i2cextend, C6DOFIMU11_I2C_SLAVE_ADDRESS_GND, C6DOFIMU11_REG_INC3, C6DOFIMU11_INC3_IEL2_FIFO_TRIG | 
                                                                                  C6DOFIMU11_INC3_IEL1_FIFO_TRIG );

    i2cextend_rmt_write ( &i2cextend, C6DOFIMU11_I2C_SLAVE_ADDRESS_GND, C6DOFIMU11_REG_CNTL2, C6DOFIMU11_CNTL2_GSEL_8G | 
                                                                                   C6DOFIMU11_CNTL2_RES_MAX2 | 
                                                                                   C6DOFIMU11_CNTL2_MAG_EN_OPERATING_MODE | 
                                                                                   C6DOFIMU11_CNTL2_ACCEL_EN_OPERATING_MODE );
    log_info( &logger, " Application Task " );
    log_printf( &logger, "------------------------\r\n" );
}

void application_task ( void ) {
    log_printf( &logger, "\t   Accel   \t|\t    Mag    \r\n" );
    log_printf( &logger, "------------------------------------------------\r\n" );
    
    i2cextend_6dofimu11_get_axis( &i2cextend, C6DOFIMU11_REG_ACCEL_XOUT_L );
    log_printf( &logger, "\t Accel X: %d\t|", axis );
    i2cextend_6dofimu11_get_axis( &i2cextend, C6DOFIMU11_REG_MAG_XOUT_L );
    log_printf( &logger, "\t Mag X: %d\r\n", axis );
    
    i2cextend_6dofimu11_get_axis( &i2cextend, C6DOFIMU11_REG_ACCEL_YOUT_L );
    log_printf( &logger, "\t Accel Y: %d\t|", axis );
    i2cextend_6dofimu11_get_axis( &i2cextend, C6DOFIMU11_REG_MAG_YOUT_L );
    log_printf( &logger, "\t Mag Y: %d\r\n", axis );
    
    i2cextend_6dofimu11_get_axis( &i2cextend, C6DOFIMU11_REG_ACCEL_ZOUT_L );
    log_printf( &logger, "\t Accel Z: %d\t|", axis );
    i2cextend_6dofimu11_get_axis( &i2cextend, C6DOFIMU11_REG_MAG_ZOUT_L );
    log_printf( &logger, "\t Mag Z: %d\r\n", axis );
    
    log_printf( &logger, "------------------------------------------------\r\n" );
    Delay_ms( 1000 );
}

void main ( void ) {
    application_init( );

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

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

Additional Support

Resources

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