Beginner
10 min

Achieve accurate current measurements with high sensitivity and low error using the CT455-H06B5-TS08 and PIC32MZ2048EFM100

XtremeSense™ TMR coreless current sensing solution

Current 10 Click with Curiosity PIC32 MZ EF

Published Oct 04, 2024

Click board™

Current 10 Click

Dev. board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Measure current usage for accurate billing and energy management with minimal error

A

A

Hardware Overview

How does it work?

Current 10 Click is based on the CT455 (CT455-H06B5-TS08), an XtremeSense™ TMR (Tunnel Magnetoresistance) coreless current sensor from Allegro Microsystems, featuring a wide bandwidth of 1MHz. This sensor uses Allegro’s patented XtremeSense™ technology, ensuring highly accurate current measurements with extremely low noise. With its high accuracy and robust features, Current 10 Click is an excellent solution for applications requiring reliable current sensing in consumer, industrial, and enterprise applications, such as solar power inverters, battery management systems, DC/DC converters, industrial equipment, and power utility meters. The CT455 sensor

operates in a bipolar mode, detecting both positive and negative current flows, and it offers a sensitivity of 333.3mV/mT, providing precise measurement capability. Powered by a 5V supply, the CT455 can sense magnetic fields in two standard ranges of ±6mT, translated into a linear analog output voltage. This allows the board to accurately capture current changes with less than ±1.0% error over varying temperatures and supply voltages, ensuring reliable performance across various operational conditions. The CT455's output signal 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 sent directly to an analog pin of the mikroBUS™ socket labeled as AN. Selection can be performed via an onboard SMD jumper labeled OUT SEL, placing it in an appropriate position marked as AN and ADC. 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 10 Click hardware overview image

Features overview

Development board

Curiosity PIC32 MZ EF development board is a fully integrated 32-bit development platform featuring the high-performance PIC32MZ EF Series (PIC32MZ2048EFM) that has a 2MB Flash, 512KB RAM, integrated FPU, Crypto accelerator, and excellent connectivity options. It includes an integrated programmer and debugger, requiring no additional hardware. Users can expand

functionality through MIKROE mikroBUS™ Click™ adapter boards, add Ethernet connectivity with the Microchip PHY daughter board, add WiFi connectivity capability using the Microchip expansions boards, and add audio input and output capability with Microchip audio daughter boards. These boards are fully integrated into PIC32’s powerful software framework, MPLAB Harmony,

which provides a flexible and modular interface to application development a rich set of inter-operable software stacks (TCP-IP, USB), and easy-to-use features. The Curiosity PIC32 MZ EF development board offers expansion capabilities making it an excellent choice for a rapid prototyping board in Connectivity, IOT, and general-purpose applications.

Curiosity PIC32MZ EF double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC32

MCU Memory (KB)

2048

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

524288

Used MCU Pins

mikroBUS™ mapper

Analog Output
RPB4
AN
NC
NC
RST
ID COMM
RPD4
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RPA14
SCL
I2C Data
RPA15
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Current 10 Click Schematic schematic

Step by step

Project assembly

Curiosity PIC32MZ EF front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity PIC32 MZ EF as your development board.

Curiosity PIC32MZ EF front image hardware assembly
GNSS2 Click front image hardware assembly
Prog-cut hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
Curiosity PIC32 MZ EF MB 1 Access - 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
Curiosity PIC32 MZ EF 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 10 Click driver.

Key functions:

  • current10_calib_offset - This function calibrates the zero current offset value.

  • current10_calib_resolution - This function calibrates the data resolution at the known load current.

  • current10_read_current - This function reads the input current level [A].

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 10 Click Example.
 *
 * # Description
 * This example demonstrates the use of Current 10 click board by reading and
 * displaying the input current measurements.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and calibrates the zero current offset and data resolution
 * at 3A load current.
 *
 * ## Application Task
 * Reads the input current measurements and displays the results on the USB UART
 * approximately once per second.
 *
 * @note
 * The measurement range is approximately: +/- 75A.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "current10.h"

// Load current [A] used for the data resolution calibration process.
#define CURRENT10_CALIBRATING_CURRENT   3.0f

static current10_t current10;   /**< Current 10 Click driver object. */
static log_t logger;    /**< Logger object. */

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    current10_cfg_t current10_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.
    current10_cfg_setup( &current10_cfg );
    CURRENT10_MAP_MIKROBUS( current10_cfg, MIKROBUS_1 );
    err_t init_flag = current10_init( &current10, &current10_cfg );
    if ( ( ADC_ERROR == init_flag ) || ( I2C_MASTER_ERROR == init_flag ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    log_printf( &logger, " Calibrating zero current offset in 5 seconds...\r\n" );
    log_printf( &logger, " Make sure no current flows through the sensor during the calibration process.\r\n" );
    for ( uint8_t cnt = 5; cnt > 0; cnt-- )
    {
        log_printf( &logger, " %u\r\n", ( uint16_t ) cnt );
        Delay_ms ( 1000 );
    }
    if ( CURRENT10_ERROR == current10_calib_offset ( &current10 ) )
    {
        log_error( &logger, " Calibrate offset." );
        for ( ; ; );
    }
    log_printf( &logger, " Offset calibration DONE.\r\n\n" );

    log_printf( &logger, " Calibrating data resolution in 5 seconds...\r\n" );
    log_printf( &logger, " Keep the load current set at %.1fA during the calibration process.\r\n", 
                CURRENT10_CALIBRATING_CURRENT );
    for ( uint8_t cnt = 5; cnt > 0; cnt-- )
    {
        log_printf( &logger, " %u\r\n", ( uint16_t ) cnt );
        Delay_ms ( 1000 );
    }
    if ( CURRENT10_ERROR == current10_calib_resolution ( &current10, CURRENT10_CALIBRATING_CURRENT ) )
    {
        log_error( &logger, " Calibrate resolution." );
        for ( ; ; );
    }
    log_printf( &logger, " Data resolution calibration DONE.\r\n" );
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    float current = 0;
    if ( CURRENT10_OK == current10_read_current ( &current10, &current ) ) 
    {
        log_printf( &logger, " Current : %.1f 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;
}

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

Additional Support

Resources

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