30 min

Identify and address power quality issues promptly with ACS37800 and PIC18LF26K42

Track and analyze power usage trends

PWR Meter 3 Click with EasyPIC v8

Published Nov 01, 2023

Click board™

PWR Meter 3 Click

Development board

EasyPIC v8


NECTO Studio



Our solution is designed to accurately measure voltage and current through your connected load, providing critical insights into electrical performance



Hardware Overview

How does it work?

PWR Meter 3 Click is based on the ACS37800, a simple solution for voltage, current, and power monitoring from Allegro MicroSystems, which simplifies the addition of power monitoring in 60Hz to many AC/DC applications. The ACS37800 includes a copper conduction path that generates a magnetic field proportional to the applied current, sensed differentially to reject errors introduced by common mode fields. It is particularly well suited for high isolation, achieving reinforced isolation ratings of 4800 VRMS and a reliable ±90A bidirectional current sensing range. With high configurability and integrated features, this Click board™ can fit most power monitoring applications. The ACS37800 measures the voltage applied to the REF terminal, in the range from 9.5 to 27V, by resistor dividing it down to fit the input range of the onboard voltage sense amplifier and

add isolation. On the other hand, the current applied to the current sensing terminals is measured using the integrated current loop and galvanically isolated Hall sensor. Both analog signals are then sampled using integrated high-accuracy ADCs before entering the digital system. The metrology engine later determines the frequency, calculates RMS values of current, voltage, and power, and provides a range of averaging and configuration options. PWR Meter 3 Click communicates with an MCU using the standard I2C 2-Wire interface to read data and configure settings, supporting Standard Mode operation with a clock frequency of 100kHz and Fast Mode up to 400kHz. The ACS37800 can be turned on, or off through the EN pin routed to the RST pin of the mikroBUS™ socket, hence offering a switch operation to turn ON/OFF power delivery

to the ACS37800 via TPS2041B. Along with the ability to measure current and voltage, it also has two LED indicators, DIO0 and DIO1, for the realization of visual detection of some anomalies in operation, such as undervoltage and overvoltage reporting, and fast overcurrent fault detection. The DIO0 LED default state application is for zero crossing, while DIO1 stands for overcurrent detection. In addition to the LEDs, this information can be detected through the INT and AN pins of the mikroBUS™ socket, marked as D0 and D1. This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

PWR Meter 3 Click hardware overview image

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC v8 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 v8 horizontal image

Microcontroller Overview

MCU Card / MCU




MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

Overcurrent Detection
Power Supply
Zero Crossing
I2C Clock
I2C Data

Take a closer look


PWR Meter 3 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

EasyPIC v8 front image hardware assembly
LTE IoT 5 Click front image hardware assembly
MCU DIP 28 hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
EasyPIC v8 28pin-DIP Access - 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
Necto image step 8 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 PWR Meter 3 Click driver.

Key functions:

  • pwrmeter3_get_dio0_pin - This function returns the DIO0 pin logic state

  • pwrmeter3_get_dio1_pin - This function returns the DIO1 pin logic state

  • pwrmeter3_read_average_rms - This function reads the voltage and current RMS measurements averaged from a specified number of samples

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 PWR Meter 3 Click example
 * # Description
 * This example demonstrates the use of PWR Meter 3 click board by reading and displaying
 * the voltage, current, and power RMS measurements.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initializes the driver and performs the click default configuration which sets the DC measurement
 * and VRMS thresholds to about 28V for overvoltage and about 9.3V for undervoltage flag.
 * ## Application Task
 * Reads the voltage and current RMS values averaged from 500 samples, then calculates the power from it
 * and displays the results on the USB UART. Also if an UV or OV flag is detected it will be logged accordingly.
 * @author Stefan Filipovic

#include "board.h"
#include "log.h"
#include "pwrmeter3.h"

static pwrmeter3_t pwrmeter3;
static log_t logger;

void application_init ( void ) 
    log_cfg_t log_cfg;  /**< Logger config object. */
    pwrmeter3_cfg_t pwrmeter3_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.
    pwrmeter3_cfg_setup( &pwrmeter3_cfg );
    PWRMETER3_MAP_MIKROBUS( pwrmeter3_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == pwrmeter3_init( &pwrmeter3, &pwrmeter3_cfg ) ) 
        log_error( &logger, " Communication init." );
        for ( ; ; );
    if ( PWRMETER3_ERROR == pwrmeter3_default_cfg ( &pwrmeter3 ) )
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    log_info( &logger, " Application Task " );

void application_task ( void ) 
    float v_rms, i_rms;
    if ( PWRMETER3_OK == pwrmeter3_read_average_rms ( &pwrmeter3, &v_rms, &i_rms, PWRMETER3_DEF_AVG_SAMPLES ) )
        if ( !pwrmeter3_get_dio0_pin ( &pwrmeter3 ) )
            log_printf ( &logger, " Over-voltage detected!\r\n" );
        if ( !pwrmeter3_get_dio1_pin ( &pwrmeter3 ) )
            log_printf ( &logger, " Under-voltage detected!\r\n" );
        log_printf ( &logger, " Voltage: %.2f V\r\n", v_rms );
        log_printf ( &logger, " Current: %.2f A\r\n", i_rms );
        log_printf ( &logger, " Power: %.2f W\r\n\n", i_rms * v_rms );

void main ( void ) 
    application_init( );

    for ( ; ; ) 
        application_task( );

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

Additional Support