Intermediate
30 min

Measure currents with the greatest precision using EMC1702 and ATmega328P

Your journey to next-level measurement and insights

Current 3 Click with Arduino UNO Rev3

Published Feb 14, 2024

Click board™

Current 3 Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Elevate safety and compliance in your operations with our current measurement solution, which facilitates accurate current monitoring, ensuring adherence to industry standards and regulations

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Hardware Overview

How does it work?

Current 3 Click is based on the EMC1702, a combination of the high-side current sensing device with precision voltage and temperature measurement capabilities from Microchip. It measures the voltage developed across an external sense resistor to represent the high-side current of a battery or voltage regulator. It also measures the source voltage and uses these measured values to present a proportional power calculation. The EMC1702 contains additional bi-directional peak detection circuitry to flag instantaneous current spikes with programmable time duration and magnitude threshold. Also, it possesses an external diode channel for temperature measurement and an internal diode for ambient temperature measurements. The EMC1702 current-sense measurement converts differential input voltage measured across an

external sense resistor to a proportional output voltage. This voltage is digitized using a variable resolution (13-bit to 15-bit) Sigma-Delta ADC and I2C protocol. The current range allows for large variations in measured current with high accuracy and a low voltage drop across the resistor. Current 3 Click communicates with MCU using the standard I2C 2-Wire interface with a maximum frequency of 400kHz. The EMC1702 slave address is determined by a resistor connected R6 (0Ω) between the ground and the ADDR_SEL pin. Various values of this resistor also provide different slave addresses (0Ω is equal to 1001_100(r/w)). The EMC1702 has two levels of monitoring and contains user-programmable bipolar Full-Scale Sense Ranges (FSSR). Each VSENSE measurement is averaged over a user-programmable time. If VSENSE exceeds (or drops below) the respective

limits, the ALERT pin, routed on the INT pin of the mikroBUS™ socket labeled as ALT, may be asserted. It also contains user-programmable current peak detection circuitry on DUR_SEL and TH_SEL pins that will assert the THERM pin, routed on the RST pin of the mikroBUS™ socket labeled as TRM, if a current spike is detected larger than the programmed threshold and of longer duration than the programmed time (threshold and duration selected by resistors R7 and R8). 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.

Current 3 Click hardware overview image

Features overview

Development board

Arduino UNO is a versatile microcontroller board built around the ATmega328P chip. It offers extensive connectivity options for various projects, featuring 14 digital input/output pins, six of which are PWM-capable, along with six analog inputs. Its core components include a 16MHz ceramic resonator, a USB connection, a power jack, an

ICSP header, and a reset button, providing everything necessary to power and program the board. The Uno is ready to go, whether connected to a computer via USB or powered by an AC-to-DC adapter or battery. As the first USB Arduino board, it serves as the benchmark for the Arduino platform, with "Uno" symbolizing its status as the

first in a series. This name choice, meaning "one" in Italian, commemorates the launch of Arduino Software (IDE) 1.0. Initially introduced alongside version 1.0 of the Arduino Software (IDE), the Uno has since become the foundational model for subsequent Arduino releases, embodying the platform's evolution.

Arduino UNO Rev3 double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

AVR

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

2048

You complete me!

Accessories

Click Shield for Arduino UNO has two proprietary mikroBUS™ sockets, allowing all the Click board™ devices to be interfaced with the Arduino UNO board without effort. The Arduino Uno, a microcontroller board based on the ATmega328P, provides an affordable and flexible way for users to try out new concepts and build prototypes with the ATmega328P microcontroller from various combinations of performance, power consumption, and features. The Arduino Uno has 14 digital input/output pins (of which six can be used as PWM outputs), six analog inputs, a 16 MHz ceramic resonator (CSTCE16M0V53-R0), a USB connection, a power jack, an ICSP header, and reset button. Most of the ATmega328P microcontroller pins are brought to the IO pins on the left and right edge of the board, which are then connected to two existing mikroBUS™ sockets. This Click Shield also has several switches that perform functions such as selecting the logic levels of analog signals on mikroBUS™ sockets and selecting logic voltage levels of the mikroBUS™ sockets themselves. Besides, the user is offered the possibility of using any Click board™ with the help of existing bidirectional level-shifting voltage translators, regardless of whether the Click board™ operates at a 3.3V or 5V logic voltage level. Once you connect the Arduino UNO board with our Click Shield for Arduino UNO, you can access hundreds of Click boards™, working with 3.3V or 5V logic voltage levels.

Click Shield for Arduino UNO accessories 1 image

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Current Peak Detection
PD2
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
PC3
INT
NC
NC
TX
NC
NC
RX
I2C Clock
PC5
SCL
I2C Data
PC4
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Current 3 Click Schematic schematic

Step by step

Project assembly

Click Shield for Arduino UNO front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Arduino UNO Rev3 as your development board.

Click Shield for Arduino UNO front image hardware assembly
Arduino UNO Rev3 front image hardware assembly
Charger 27 Click front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Board mapper by product8 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
Arduino UNO 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 Current 3 Click driver.

Key functions:

  • current3_get_temperature - The function get the temperature by read multiple data bytes from a group of contiguous registers

  • current3_get_source_voltage - The function source voltage registers store the voltage measured at the SENSE+ pin

  • current3_get_current - The function current measurement measure the direction of current flow ( from SENSE+ to SENSE- or from SENSE- to SENSE+ )

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 
 * \brief Current3 Click example
 * 
 * # Description
 * Current 3 Click can be used to measure current ranging up to 8000mA, and display temperature, 
 * voltage and current data - using I2C comunication.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initialization driver enables - I2C,
 * check communication and set sense sampling configuration, also write log.
 * 
 * ## Application Task  
 * This is an example which demonstrates the use of Current 3  Click board.
 * Current 3 Click board can be used to measure current ranging
 * up to 8000mA, and display temperature, voltage and current data.
 * All data logs write on USB uart changes for every 2 sec.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "current3.h"

// ------------------------------------------------------------------ VARIABLES

static current3_t current3;
static log_t logger;
static current3_sense_cfg_data_t sense_cfg_data;

static float temperature;
static float voltage;
static float current;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    current3_cfg_t cfg;
    uint8_t read_data;

    /** 
     * 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.

    current3_cfg_setup( &cfg );
    CURRENT3_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    current3_init( &current3, &cfg );

    Delay_ms ( 100 );
    log_printf( &logger, "     Driver init. done     \r\n" );
    log_printf( &logger, "---------------------------\r\n" );
    
    current3_generic_read( &current3, CURRENT3_REG_PRODUCT_ID, &read_data, 1 );
    if ( read_data == CURRENT3_DEV_ID )
    {
        log_printf( &logger, "     Communication OK      \r\n" );
        log_printf( &logger, "---------------------------\r\n" );
    }
    else
    {
        log_printf( &logger, "    Communication ERROR    \r\n" );
        log_printf( &logger, "     Reset the device      \r\n" );
        log_printf( &logger, "---------------------------\r\n" );
        for ( ; ; );
    }
    
    current3_default_cfg( &current3, sense_cfg_data );
}

void application_task ( void )
{
    temperature = current3_get_temperature( &current3, CURRENT3_TEMP_INTERNAL_DIODE );
    log_printf( &logger, " Temperature = %.2f C\r\n", temperature );

    voltage = current3_get_source_voltage( &current3 );
    log_printf( &logger, " Voltage     = %.2f V\r\n", voltage );

    current = current3_get_current( &current3 );
    log_printf( &logger, " Current     = %.2f mA\r\n", current );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms ( 1000 );
    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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