Manage currents seamlessly across diverse applications with ACS723 and ATmega644

Excellence with every Ampere

Published Aug 11, 2023

Click board™

Hall Current 6 Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega644

Engineered for efficiency enhancement, our current measurement solution provides dependable monitoring, seamless management, and insightful analysis of currents across applications

Hardware Overview

How does it work?

Hall Current 6 Click is based on the ACS723, a high-accuracy, galvanically isolated current sensor IC from Allegro Microsystems. This sensor utilizes the Hall effect phenomenon to measure the current passing through the internally fused input pins of the IC. This allows the series resistance to stay very low. Current through the input rails of the IC generates a magnetic field, causing the Hall effect on the current through the integrated sensor. These two current circuits are completely isolated, with the basic isolation working voltage of about 297VRMS, allowing the Click board™ to be used in high-side current sensing applications. The output voltage changes linearly with the current in the primary circuit, with the ratio of 400mV/A, and it is fed to the MCP3221, a 12-bit analog to digital converter (ADC) with I2C interface, from Microchip. This is a well-established converter used in many Click board™ designs, thanks to its proven reliability, reasonably good sampling rate well suited for instrumentation applications (22.3 kbps),

and simplicity of use. It converts the output voltage from the ACS723 into a digital value, which is available over the I2C interface. The output voltage of the ACS723 has a very linear dependency on the current through the primary pins due to Allegro's patented digital temperature compensation. Although it can be used in a rather limited current range of ±5A, it has a great accuracy of ±3% (referred to as a Total Output Error in the datasheet). The ACS723 IC features a bandwidth selection pin, which allows the bandwidth selection according to the application it is used in. For example, when measuring current in some applications that operate at lower frequencies, limiting the bandwidth improves the noise performance, enabling to obtain results with higher accuracy. The bandwidth selection pin acts as a filter on the measurement line, allowing two cutoff frequencies: 20kHz and 80kHz. The BW_SEL pin of the ACS723 is routed to the small SMD jumper, labeled as BW SEL. When the jumper is at position

0, the device's bandwidth is 80kHz. The secondary side of the ACS733 is powered by the 5V mikroBUS™ rail. As explained earlier, current flowing through the primary conductors is galvanically isolated from the rest of the IC, protecting low-voltage parts of the Click board™, as well as the host MCU. The Click board™ should be connected in series with the load through which the current is measured using the load connector labeled with IP+ and IP-. A low internal resistance of only 0.65 mΩ across the primary conductors will not disturb the current through the circuit, so the Click board™ will not introduce its error into the measurement, thus acting as a nearly-perfect ammeter. The voltage at which the I2C lines are pulled up can be selected using the VCC SEL jumper. Selecting the logic voltage level allows this Click board™ to be interfaced with a wide range of MCUs operating at 3.3V and 5V.

Hall Current 6 Click hardware overview image

Hall Current 6 Click Current Warning image

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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.

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

4096

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

PC0

SCL

I2C Data

PC1

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Hall Current 6 Click Schematic schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

EasyAVR v7 Access DIP MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection 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 Hall Current 6 Click driver.

Key functions:

hallcurrent6_read_data - Reads ADC current data
hallcurrent6_get_current - Reads current data
hallcurrent6_generic_read - Generic read 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 
 * \brief HallCurrent6 Click example
 * 
 * # Description
 * This application reads current data.
 * 
 * The application is composed of two sections :
 * 
 * ## Application Init 
 * Initializations driver init
 * 
 * ## Application Task  
 * Reads Current data in mA and logs this data to USBUART every 1 sec.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "hallcurrent6.h"

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

static hallcurrent6_t hallcurrent6;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    hallcurrent6_cfg_t cfg;

    /** 
     * 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.

    hallcurrent6_cfg_setup( &cfg );
    HALLCURRENT6_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    hallcurrent6_init( &hallcurrent6, &cfg );

    log_printf( &logger, "---- App Init Done ----\r\n" );
}

void application_task ( void )
{
    float current;

    current = hallcurrent6_get_current( &hallcurrent6 );
    log_printf( &logger, " Current value: %.2f mA \r\n" , current);
    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