30 min

Achieve the highest level of precision in power monitoring with INA228 and PIC18F26K22

Power insight redefined: Elevate performance with ultra-precise monitoring

Power Monitor Click with Curiosity HPC

Published Jan 23, 2024

Click board™

Power Monitor Click

Development board

Curiosity HPC


NECTO Studio



Our ultra-precise power monitoring solution redefines how you gain insight into your power usage, offering unmatched accuracy for optimizing performance, reducing costs, and ensuring the reliability of your systems



Hardware Overview

How does it work?

Power Monitor Click is based on the INA228, an ultra-precise digital power monitor with a 20-bit delta-sigma ADC and I2C digital interface from Texas Instruments. It measures shunt voltage, bus voltage, and internal temperature while calculating the current, power, energy, and charge necessary for accurate decisions in precisely controlled systems. It can measure a full-scale differential input of ±163.84mV or ±40.96mV across a resistive shunt sense element connected on the onboard IN terminal alongside common-mode voltage support up to +85V, which makes it well suited for both high-side and low-side current measurements. The INA228 also measures the bus supply voltage through the VBUS terminal and temperature through the integrated ±1°C accurate temperature sensor, which helps monitor the ambient system temperature. Power, charge, and energy calculations are performed in the

background and do not add to the overall ADC conversion time. Also, the very low offset voltage and noise allow for use in mA to kA sensing applications and provide a wide dynamic range without significant power dissipation losses on the sensing shunt element. Power Monitor Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting a Fast Mode operation up to 400kHz. The INA228 also allows the selection of its I2C slave address using the two SMD cross-shape jumpers labeled A0 and A1. One cross-shape jumper has four positions for select address pins, which can be connected to GND, VS, SCL, or SDA pins. This way, the INA228 provides the opportunity of the 16 possible different I2C addresses by positioning the SMD jumper to an appropriate position. Besides, the INA228 also includes the multipurpose alert(interrupt) pin,

labeled as ALR and routed to the INT pin of the mikroBUS™ socket, used to report multiple diagnostics or as an indicator that the ADC conversion is complete when the device is operating in both triggered and continuous conversion mode. The diagnostics such as shunt over/under voltage limit, bus over/under voltage limit, or temperature or power over-limit are constantly monitored and reported through the ALR pin whenever the monitored output value crosses its associated out-of-range threshold. 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.

Power Monitor Click hardware overview image

Features overview

Development board

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Curiosity HPC double image

Microcontroller Overview

MCU Card / MCU




MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Power Supply
Alert Interrupt
I2C Clock
I2C Data
Power Supply

Take a closer look


Power Monitor Click Schematic schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

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

Curiosity HPC front no-mcu image hardware assembly
LTE Cat.1 2 Click front image hardware assembly
MCU DIP 28 hardware assembly
Prog-cut hardware assembly
LTE Cat.1 2 Click complete accessories setup image hardware assembly
Curiosity HPC Access 28pin-DIP - 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
Necto DIP image step 7 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

After loading the code example, pressing the "DEBUG" button builds and programs it on the selected setup.

Application Output Step 1

After programming is completed, a header with buttons for various actions available in the IDE appears. By clicking the green "PLAY "button, we start reading the results achieved with Click board™.

Application Output Step 3

Upon completion of programming, the Application Output tab is automatically opened, where the achieved result can be read. In case of an inability to perform the Debug function, check if a proper connection between the MCU used by the setup and the CODEGRIP programmer has been established. A detailed explanation of the CODEGRIP-board connection can be found in the CODEGRIP User Manual. Please find it in the RESOURCES section.

Application Output Step 4

Software Support

Library Description

This library contains API for Power Monitor Click driver.

Key functions:

  • powermonitor_get_vshunt - Power Monitor get shunt voltage function

  • powermonitor_get_vbus - Power Monitor get bus voltage function

  • powermonitor_get_current - Power Monitor get current function

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 PowerMonitor Click example
 * # Description
 * This library contains API for Power Monitor Click driver.
 * The library initializes and defines the I2C bus drivers 
 * to write and read data from registers. 
 * The library also includes a function for reading 
 * Shunt and Bus voltage ( mV ), Current ( mA ), Power ( W ), Energy ( J ),   
 * as well as the Temperature in degrees Celsius.
 * The demo application is composed of two sections :
 * ## Application Init
 * The initialization of I2C  module, log UART, and additional pins. 
 * After the driver init and then executes a default configuration, 
 * the app checks communication, display Manufacturer, Stores Device and Revision ID. 
 * ## Application Task
 * This is an example that shows the use of a Power Monitor Click board™.
 * Measures and displays Shunt voltage ( mV ), Bus voltage ( mV ), 
 * Current ( mA ), Power ( W ), Energy ( J ) and Temperature ( degrees Celsius ). 
 * Results are being sent to the USART terminal where the user can track their changes. 
 * This task repeats every 2.5 sec.
 * @author Nenad Filipovic

#include "board.h"
#include "log.h"
#include "powermonitor.h"

static powermonitor_t powermonitor;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;                    /**< Logger config object. */
    powermonitor_cfg_t powermonitor_cfg;  /**< Click config object. */
    static uint8_t manufacturer_id[ 2 ];
    static uint16_t dieid;
    static uint8_t rev_id;
    powermonitor.shunt = 0.28;

     * 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.
    powermonitor_cfg_setup( &powermonitor_cfg );
    POWERMONITOR_MAP_MIKROBUS( powermonitor_cfg, MIKROBUS_1 );
    err_t init_flag = powermonitor_init( &powermonitor, &powermonitor_cfg );
    if ( I2C_MASTER_ERROR == init_flag ) 
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );

    powermonitor_default_cfg ( &powermonitor );
    log_printf( &logger, "----------------------------\r\n" );
    Delay_ms( 100 );
    powermonitor_get_id( &powermonitor, &manufacturer_id, &dieid, &rev_id );
    log_printf( &logger, "  Manufacturer ID  : %.2s\r\n", manufacturer_id );
    log_printf( &logger, "  Stores Device ID : 0x%.3X\r\n", dieid );
    log_printf( &logger, "  Revision ID      : 0x%.1X\r\n", rev_id );
    log_printf( &logger, "----------------------------\r\n" );
    log_info( &logger, " Application Task " );
    log_printf( &logger, "----------------------------\r\n" );
    Delay_ms( 100 );

void application_task ( void ) 
    static float vshunt, vbus, current, power, energy, temperature;
    powermonitor_get_vshunt( &powermonitor, &vshunt );
    log_printf( &logger, " Shunt voltage : %.2f mV\r\n", vshunt );
    Delay_ms( 100 ); 
    powermonitor_get_vbus( &powermonitor, &vbus );
    log_printf( &logger, " BUS voltage   : %.2f mV\r\n", vbus );
    Delay_ms( 100 );
    powermonitor_get_current( &powermonitor, &current );
    log_printf( &logger, " Current       : %.2f mA\r\n", current );
    Delay_ms( 100 ); 
    powermonitor_get_power( &powermonitor, &power );
    log_printf( &logger, " Power         : %.6f W\r\n", power );
    Delay_ms( 100 ); 
    powermonitor_get_energy( &powermonitor, &energy );
    log_printf( &logger, " Energy        : %.6f J\r\n", energy );
    log_printf( &logger, "- - - - - - - - - - - - - - \r\n" );
    Delay_ms( 100 ); 
    powermonitor_get_temperature( &powermonitor, &temperature );
    log_printf( &logger, " Temperature   : %.2f C\r\n", temperature );
    log_printf( &logger, "----------------------------\r\n" );
    Delay_ms( 2000 );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support