Measure a wide range of current values using CT415 and ATmega328P

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Published Feb 14, 2024

Click board™

Current 9 Click

Dev. board

Arduino UNO Rev3

Compiler

NECTO Studio

MCU

ATmega328P

Precise and accurate current sensing solution

Hardware Overview

How does it work?

Current 9 Click is based on the CT415-HSN830DR, an XtremeSense® TMR current sensor providing high-accuracy current measurements from Crocus Technology. The CT415-HSN830DR has an integrated current-carrying conductor (CCC) that handles the current from 0A up to 30A. It has high sensitivity and a wide dynamic range with excellent accuracy (low total output error), making it suitable for many consumer, enterprise, and industrial applications. When current flows through the CCC, the XtremeSense® TMR sensors inside the chip sense the field, generating a differential voltage signal that goes through the analog front-end to output a current measurement with less than ±1% full-scale total output error. The CT415-HSN830DR

is designed to enable a fast response time for the current measurement. In addition, the user can select the output voltage level of the sensor performed by the onboard SMD jumper by populating it to an appropriate position marked as 3V3 or 5V. Even with high bandwidth of 1MHz, the CT415-HSN830DR consumes minimal power. The output signal of the CT415-HSN830DR can be converted to a digital value using MCP3221, a successive approximation A/D converter with a 12-bit resolution from Microchip using a 2-wire I2C compatible interface, or can be sent directly to an analog pin of the mikroBUS™ socket labeled as AN. The selection can be made by an onboard SMD jumper labeled ADC SEL, placing it in an

appropriate position marked as EXT and INT. Also, this Click board™ should be connected in series with the load. Two onboard terminal connectors measure the current, one terminal block for the positive and the other for the negative current input. 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. However, the 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.

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.

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

2048

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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.

Used MCU Pins

mikroBUS™ mapper

Analog Signal

PC0

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

PC5

SCL

I2C Data

PC4

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ 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.

Arduino UNO Rev3 front image hardware assembly

Charger 27 Click front image hardware assembly

Charger 27 Click complete accessories setup image hardware assembly

Board mapper by product8 hardware assembly

Necto No Display image step 8 hardware assembly

Debug Image Necto Step hardware assembly

Software Support

Library Description

This library contains API for Current 9 Click driver.

Key functions:

current9_read_voltage This function reads the raw ADC value and converts it to a proportional voltage level.
current9_read_current This function reads the input current level [A] based on @b CURRENT9_NUM_CONVERSIONS of voltage measurements.
current9_set_vref This function sets the voltage reference for the Current 9 Click driver.

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 Current 9 Click Example.
 *
 * # Description
 * This example demonstrates the use of Current 9 Click board by reading and
 * displaying the input current measurements.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger.
 *
 * ## Application Task
 * Reads the input current measurements and displays the results on the USB UART
 * approximately once per second.
 *
 * @note
 * For better accuracy, set the voltage reference by using the @b current9_set_vref function,
 * increase the number of conversions by modifying the @b CURRENT9_NUM_CONVERSIONS macro, 
 * and adjust the @b CURRENT9_ZERO_CURRENT_OFFSET voltage value.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "current9.h"

static current9_t current9;   /**< Current 9 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    current9_cfg_t current9_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.
    current9_cfg_setup( &current9_cfg );
    CURRENT9_MAP_MIKROBUS( current9_cfg, MIKROBUS_1 );
    err_t init_flag = current9_init( &current9, &current9_cfg );
    if ( ( ADC_ERROR == init_flag ) || ( I2C_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    float current = 0;
    if ( CURRENT9_OK == current9_read_current ( &current9, &current ) ) 
    {
        log_printf( &logger, " Current : %.3f[A]\r\n\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;
}

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