Intermediate
30 min

Experience uninterrupted I2C communication across extended distances with PCA9615 and PIC18F57Q43

Expand, Connect, Thrive: Your I2C bus extension solution!

I2C Extend 2 Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

I2C Extend 2 Click

Dev. board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

Expand the possibilities of your I2C-enabled projects with ease, thanks to our bus extension solution, designed to simplify the integration of remote sensors, displays, and control devices

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Hardware Overview

How does it work?

I2C Extend 2 Click is based on the PCA9615, a Fast-Mode Plus (FM+) I2C bus buffer that extends the single-ended I2C bus through electrically noisy environments from NXP Semiconductor. It consists of two single-ended to differential driver channels for the SCL (Serial Clock) and SDA (Serial Data). Differential transmission lines between identical I2C bus buffers remove electrical noise and common-mode offsets when signals pass between different voltage domains, such as high-energy power supplies and electric motors. Those signals can reach up to 3m or longer at lower clock speeds while maintaining signal integrity sent over an Ethernet cable (a twisted-pair transmission line cable) through the onboard RJ-45 connector. The PCA9615 converts the default I2C signals into four differential signals, two for SCL and two for SDA. The signal direction is

determined by the I2C protocol, which means it does not require a direction signal, as these bus buffers automatically set signal flow direction. Additional circuitry allows the PCA9615 to be used for ‘hot-swap’ applications, where systems are always ON but require insertion or removal of modules or cards without disrupting existing signals. Because the supply voltages on the I2C bus side may differ from the external I2C bus side, there are two power supply pins and common ground. The first is a standard I2C bus-side power supply selected via the VCC SEL jumper, and the other represents the majority supply for circuitry determined by the VDD SEL jumper. I2C Extend 2 Click communicates with MCU using the standard I2C interface with a frequency of up to 100kHz in the Standard 400kHz in the Fast Mode and up to 1MHz in the Fast Mode Plus. The user must be

cautious not to overload the driver's current rating of 3mA for Standard and Fast Modes and 30mA for Fast Mode Plus (FM+). Also, this Click board™ has an Enable pin, routed on the CS pin of the mikroBUS™ socket labeled as EN, used to turn off the bus buffer, and is useful for fault finding, Power-Up sequencing, or re-configuration of a bus system by isolating sections not needed at all times. 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 2 Click top side image
I2C Extend 2 Click bottom side image

Features overview

Development board

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
Enable
PD4
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
NC
NC
TX
NC
NC
RX
I2C Clock
PB2
SCL
I2C Data
PB1
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

I2C Extend 2 Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
PIC18F57Q43 Curiosity 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 2 Click driver.

Key functions:

  • i2cextend2_rmt_write - Generic write data in Remote Mode function

  • i2cextend2_rmt_read - Generic read data in Remote Mode function

  • i2cextend2_enable - Enable extend 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 I2CExtend2 Click example
 *
 * # Description
 * This is an example which demonstrates the use of I2C Extend 2 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 2 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 2 Click ( Remote Mode )
 * which is connected by a LAN cable to I2C Extend 2 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 "i2cextend2.h"

static i2cextend2_t i2cextend2;
static log_t logger;
int16_t axis;

void i2cextend2_6dofimu11_get_axis ( i2cextend2_t *ctx, uint8_t axis_out_reg ) 
{
    uint16_t rx_val = 0;

    rx_val = i2cextend2_rmt_read( ctx, axis_out_reg + 1 );
    rx_val <<= 8;
    rx_val |= i2cextend2_rmt_read( ctx, axis_out_reg );

    axis = ( int16_t ) rx_val;
}

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    i2cextend2_cfg_t i2cextend2_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.
    i2cextend2_cfg_setup( &i2cextend2_cfg );
    I2CEXTEND2_MAP_MIKROBUS( i2cextend2_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == i2cextend2_init( &i2cextend2, &i2cextend2_cfg ) ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    i2cextend2_enable( &i2cextend2, I2CEXTEND2_EXTEND_ENABLE );

    if ( C6DOFIMU11_WHO_AM_I_WIA_ID == i2cextend2_rmt_read( &i2cextend2, C6DOFIMU11_REG_WHO_AM_I ) ) 
    {
        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 ( ; ; );
    }
    i2cextend2_rmt_write ( &i2cextend2, C6DOFIMU11_REG_CNTL2, C6DOFIMU11_CNTL2_TEMP_EN_STANDBY_MODE |
                                                              C6DOFIMU11_CNTL2_MAG_EN_STANDBY_MODE |
                                                              C6DOFIMU11_CNTL2_ACCEL_EN_STANDBY_MODE );

    i2cextend2_rmt_write ( &i2cextend2, C6DOFIMU11_REG_INC3, C6DOFIMU11_INC3_IEL2_FIFO_TRIG |
                                                             C6DOFIMU11_INC3_IEL1_FIFO_TRIG );

    i2cextend2_rmt_write ( &i2cextend2, C6DOFIMU11_REG_CNTL2, C6DOFIMU11_CNTL2_GSEL_8G |
                                                              C6DOFIMU11_CNTL2_RES_MAX2 |
                                                              C6DOFIMU11_CNTL2_MAG_EN_OPERATING_MODE |
                                                              C6DOFIMU11_CNTL2_ACCEL_EN_OPERATING_MODE );
    Delay_ms ( 100 );
    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" );

    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_ACCEL_XOUT_L );
    log_printf( &logger, "\t Accel X: %d\t|", axis );
    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_MAG_XOUT_L );
    log_printf( &logger, "\t Mag X: %d\r\n", axis );

    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_ACCEL_YOUT_L );
    log_printf( &logger, "\t Accel Y: %d\t|", axis );
    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_MAG_YOUT_L );
    log_printf( &logger, "\t Mag Y: %d\r\n", axis );

    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_ACCEL_ZOUT_L );
    log_printf( &logger, "\t Accel Z: %d\t|", axis );
    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_MAG_ZOUT_L );
    log_printf( &logger, "\t Mag Z: %d\r\n", axis );

    log_printf( &logger, "------------------------------------------------\r\n" );
    Delay_ms ( 1000 );
}

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
/*!
 * @file main.c
 * @brief I2CExtend2 Click example
 *
 * # Description
 * This is an example which demonstrates the use of I2C Extend 2 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 2 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 2 Click ( Remote Mode )
 * which is connected by a LAN cable to I2C Extend 2 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 "i2cextend2.h"

static i2cextend2_t i2cextend2;
static log_t logger;
int16_t axis;

void i2cextend2_6dofimu11_get_axis ( i2cextend2_t *ctx, uint8_t axis_out_reg ) 
{
    uint16_t rx_val = 0;

    rx_val = i2cextend2_rmt_read( ctx, axis_out_reg + 1 );
    rx_val <<= 8;
    rx_val |= i2cextend2_rmt_read( ctx, axis_out_reg );

    axis = ( int16_t ) rx_val;
}

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    i2cextend2_cfg_t i2cextend2_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.
    i2cextend2_cfg_setup( &i2cextend2_cfg );
    I2CEXTEND2_MAP_MIKROBUS( i2cextend2_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == i2cextend2_init( &i2cextend2, &i2cextend2_cfg ) ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    i2cextend2_enable( &i2cextend2, I2CEXTEND2_EXTEND_ENABLE );

    if ( C6DOFIMU11_WHO_AM_I_WIA_ID == i2cextend2_rmt_read( &i2cextend2, C6DOFIMU11_REG_WHO_AM_I ) ) 
    {
        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 ( ; ; );
    }
    i2cextend2_rmt_write ( &i2cextend2, C6DOFIMU11_REG_CNTL2, C6DOFIMU11_CNTL2_TEMP_EN_STANDBY_MODE |
                                                              C6DOFIMU11_CNTL2_MAG_EN_STANDBY_MODE |
                                                              C6DOFIMU11_CNTL2_ACCEL_EN_STANDBY_MODE );

    i2cextend2_rmt_write ( &i2cextend2, C6DOFIMU11_REG_INC3, C6DOFIMU11_INC3_IEL2_FIFO_TRIG |
                                                             C6DOFIMU11_INC3_IEL1_FIFO_TRIG );

    i2cextend2_rmt_write ( &i2cextend2, C6DOFIMU11_REG_CNTL2, C6DOFIMU11_CNTL2_GSEL_8G |
                                                              C6DOFIMU11_CNTL2_RES_MAX2 |
                                                              C6DOFIMU11_CNTL2_MAG_EN_OPERATING_MODE |
                                                              C6DOFIMU11_CNTL2_ACCEL_EN_OPERATING_MODE );
    Delay_ms ( 100 );
    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" );

    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_ACCEL_XOUT_L );
    log_printf( &logger, "\t Accel X: %d\t|", axis );
    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_MAG_XOUT_L );
    log_printf( &logger, "\t Mag X: %d\r\n", axis );

    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_ACCEL_YOUT_L );
    log_printf( &logger, "\t Accel Y: %d\t|", axis );
    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_MAG_YOUT_L );
    log_printf( &logger, "\t Mag Y: %d\r\n", axis );

    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_ACCEL_ZOUT_L );
    log_printf( &logger, "\t Accel Z: %d\t|", axis );
    i2cextend2_6dofimu11_get_axis( &i2cextend2, C6DOFIMU11_REG_MAG_ZOUT_L );
    log_printf( &logger, "\t Mag Z: %d\r\n", axis );

    log_printf( &logger, "------------------------------------------------\r\n" );
    Delay_ms ( 1000 );
}

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

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