Beginner
10 min

Measure how much electrical current is flowing through a circuit with INA196 and PIC18F57Q43

Current sensing has never been this electrifying!

Current Click with Curiosity Nano with PIC18F57Q43

Published Feb 13, 2024

Click board™

Current Click

Dev Board

Curiosity Nano with PIC18F57Q43

Compiler

NECTO Studio

MCU

PIC18F57Q43

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

PIC18F57Q43 Curiosity Nano evaluation kit is a cutting-edge hardware platform designed to evaluate microcontrollers within the PIC18-Q43 family. Central to its design is the inclusion of the powerful PIC18F57Q43 microcontroller (MCU), offering advanced functionalities and robust performance. Key features of this evaluation kit include a yellow user LED and a responsive

mechanical user switch, providing seamless interaction and testing. The provision for a 32.768kHz crystal footprint ensures precision timing capabilities. With an onboard debugger boasting a green power and status LED, programming and debugging become intuitive and efficient. Further enhancing its utility is the Virtual serial port (CDC) and a debug GPIO channel (DGI

GPIO), offering extensive connectivity options. Powered via USB, this kit boasts an adjustable target voltage feature facilitated by the MIC5353 LDO regulator, ensuring stable operation with an output voltage ranging from 1.8V to 5.1V, with a maximum output current of 500mA, subject to ambient temperature and voltage constraints.

PIC18F57Q43 Curiosity Nano double side image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

48

RAM (Bytes)

8196

You complete me!

Accessories

Curiosity Nano Base for Click boards is a versatile hardware extension platform created to streamline the integration between Curiosity Nano kits and extension boards, tailored explicitly for the mikroBUS™-standardized Click boards and Xplained Pro extension boards. This innovative base board (shield) offers seamless connectivity and expansion possibilities, simplifying experimentation and development. Key features include USB power compatibility from the Curiosity Nano kit, alongside an alternative external power input option for enhanced flexibility. The onboard Li-Ion/LiPo charger and management circuit ensure smooth operation for battery-powered applications, simplifying usage and management. Moreover, the base incorporates a fixed 3.3V PSU dedicated to target and mikroBUS™ power rails, alongside a fixed 5.0V boost converter catering to 5V power rails of mikroBUS™ sockets, providing stable power delivery for various connected devices.

Curiosity Nano Base for Click boards accessories 1 image

Used MCU Pins

mikroBUS™ mapper

Analog Output
PA0
AN
NC
NC
RST
SPI Chip Select
PD4
CS
SPI Clock
PC6
SCK
SPI Data OUT
PC5
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

Schematic

Current Click Schematic schematic

Step by step

Project assembly

Curiosity Nano Base for Click boards front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity Nano with PIC18F57Q43 as your development board.

Curiosity Nano Base for Click boards front image hardware assembly
Charger 27 Click front image hardware assembly
PIC18F47Q10 Curiosity Nano front image hardware assembly
Prog-cut hardware assembly
Charger 27 Click complete accessories setup image hardware assembly
Curiosity Nano with PICXXX Access MB 1 - 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
PIC18F57Q43 Curiosity 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 via Debug Mode

1. Once the code example is loaded, pressing the "DEBUG" button initiates the build process, programs it on the created setup, and enters Debug mode.

2. After the programming is completed, a header with buttons for various actions within the IDE becomes visible. Clicking the green "PLAY" button starts reading the results achieved with the Click board™. The achieved results are displayed in the Application Output tab.

DEBUG_Application_Output

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

This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.

/*!
 * \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 ) 
{
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}

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

Additional Support

Resources

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