Beginner
10 min

Measure how much electrical current is flowing through a circuit with INA196 and PIC32MZ2048EFM100

Current sensing has never been this electrifying!

Current Click with Curiosity PIC32 MZ EF

Published Jan 31, 2024

Click board™

Current Click

Dev. board

Curiosity PIC32 MZ EF

Compiler

NECTO Studio

MCU

PIC32MZ2048EFM100

Achieve precise current measurements (from 2mA up to 2Amps) by sensing voltage drops across the added shunt resistor

A

A

Hardware Overview

How does it work?

Current Click is based on the INA196, a current shunt monitor from Texas Instruments. The INA196 has a voltage output that can sense drops across shunts at common-mode voltages from −16V to +80V, independent of its supply voltage. It is also characterized by a gain of 20V/V and 500kHz bandwidth, simplifying current control loops' use across a vast temperature range, making it suitable for many consumer, enterprise, telecom, and automotive applications. This Click board™ measures current values in various bands. The board receives current from the output circuit connected to IN(+) and OUT(-) pins of the first

screw terminal, where the INA196 converts this current into a voltage, while the second screw terminal is used for the external shunt connection. Users need to provide the shunt of the appropriate value allowing the measurement up to 2048mA, based on the reference voltage set by MAX6106. Therefore, four shunts with different values are provided in the package (0.05, 0.2, 1, and 10Ω). The output signal of the INA196 can be converted to a digital value using MCP3201, a successive approximation A/D converter with a 12-bit resolution from Microchip using a 3-wire SPI compatible interface, or can be sent directly

to an analog pin of the mikroBUS™ socket labeled as AN. Selection can be performed by onboard SMD jumper labeled as OUTPUT, placing it in an appropriate position marked as AN or ADC. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWRSEL 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.

Current 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
SPI Chip Select
RPD4
CS
SPI Clock
RPD1
SCK
SPI Data OUT
RPD14
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
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

Current 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 Click driver.

Key functions:

  • current_get_current_data - This function calculates the current in mA

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 Current Click example
 * 
 * # Description
 * This is an example that shows the capabilities of the Current Click board 
 * by measuring current in miliampers. Current Click board can be used to safely
 * measure DC current in the range of 2-2048mA depending on shunt resistor.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initalizes SPI, LOG and Click drivers.
 * 
 * ## Application Task  
 * Measures DC current and displays the results on USB UART each second.
 * 
 * @note
 * Shunt resistor used in the example covers 4 default values (0.05 Ohm, 0.2 Ohm, 1 Ohm, 10 Ohm).
 * To operate in linear range of INA196 check table bellow for shunt selection.
 * |------------------------------------|
 * | Rshunt  | Imin [mA]  | Imax  [mA]  |
 * |------------------------------------|
 * |   0.05  |    400     |   2048      |
 * |   0.2   |    100     |    512      |
 * |   1     |     20     |    102      |
 * |  10     |      2     |     10      |
 * --------------------------------------
 * 
 * \author Jovan Stajkovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "current.h"

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

static current_t current;
static log_t logger;
static float curr;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    current_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.

    current_cfg_setup( &cfg );
    CURRENT_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    current_init( &current, &cfg );
    log_printf( &logger, "-----------------------\r\n" );
    log_printf( &logger, "    Current  Click     \r\n" );
    log_printf( &logger, "-----------------------\r\n" );
}

void application_task ( void )
{
    curr = current_get_current_data( &current, CURRENT_RSHUNT_0_05 );
    
    if ( curr == CURRENT_OUT_OF_RANGE )
    {
        log_printf( &logger, "Out of range!\r\n" );
    }
    else
    {
       log_printf( &logger, " Current: %.2f mA\r\n", curr );
    }
    
    log_printf( &logger, "-----------------------\r\n" );
    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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