Intermediate
30 min

Achieve better safety and performance for your projects with MAX14575A and PIC18LF26K22

Elevate performance with our current limiter

Current Limit 7 Click with EasyPIC v8

Published Nov 01, 2023

Click board™

Current Limit 7 Click

Dev Board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18LF26K22

Empower your projects with the versatility and precision of our current limiting solution, providing dynamic current management for improved safety, energy efficiency, and reliability

A

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Hardware Overview

How does it work?

Current Limit 7 Click is based on the MAX14575A, a programmable current-limit switch featuring internal current limiting to prevent damage to host devices due to faulty load conditions from Analog Devices. The MAX14575A offers flexible protection boundaries for systems against input voltage ranging from 2.3V to 5.5V. It limits the output load current to a programmed level, up to 2.5A, making this device ideal for charging a large load capacitor and high-current load switching applications. Additional safety features include thermal shutdown protection to prevent overheating and reverse current blocking to prevent current from being driven back into the source. The current-limit switch provides a safe means for regulating the current delivered to a load circuit. It increases the load current to a programmed limit but no higher. Typically, the

current limit is a function of the voltage across an external resistor, and this voltage serves as the reference for an internal current-limiting amplifier. By replacing the resistor with a digital rheostat, you can easily program the current limit as performed on this Click board™. For this purpose, the AD5272 from Analog Devices, communicating with the MCU via a 2-wire I2C interface, is used to set the resistance on the MAX14575A SETI pin, adjusting the current limit for the switch. In this case, two rheostats were combined with an onboard switch labeled as RANGE, allowing the user to use two possible current limit ranges: from 0.5A to 2.5A and 0.25A to 0.5A. Current Limit 7 Click can be turned on, or off through the EN pin routed to the CS pin of the mikroBUS™ socket, hence offering a switch operation to turn ON/OFF power delivery to the connected load. It also provides an

overcurrent flag (FLG) indication signal routed to the INT pin of the mikroBUS™ socket and an additional reset signal for AD5272 digital rheostat routed to the RST pin of the mikroBUS™ socket. This Click board™ can operate with both 3.3V and 5V logic voltage levels selected via the VCC SEL jumper. It allows both 3.3V and 5V capable MCUs to use the communication lines properly. Additionally, there is a possibility for the MAX14575A power supply selection via jumper labeled as PWR SEL to supply the MAX14575A from an external power supply terminal in the range from 2.3V to 5.5V or with VCC voltage levels from mikroBUS™ power rails. 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 Limit 7 Click hardware overview image

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC v8 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.

EasyPIC v8 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3896

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RA0
RST
Enable
RA5
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Overcurrent Interrupt
RB1
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
Power Supply
5V
5V
Ground
GND
GND
2

Take a closer look

Click board™ Schematic

Current Limit 7 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

EasyPIC v8 front image hardware assembly
LTE IoT 5 Click front image hardware assembly
MCU DIP 28 hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
EasyPIC v8 28pin-DIP Access - upright/background hardware assembly
Necto image step 2 hardware assembly
Necto image step 3 hardware assembly
Necto image step 4 hardware assembly
NECTO Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
Necto image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Necto PreFlash Image 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 Limit 7 Click driver.

Key functions:

  • currentlimit7_set_current_limit - Current Limit 7 set current limit function

  • currentlimit7_set_resistance - Current Limit 7 set resistance function

  • currentlimit7_get_fault - Current Limit 7 get fault 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 main.c
 * @brief CurrentLimit7 Click example
 *
 * # Description
 * This library contains API for the Current Limit 7 Click driver.
 * This driver provides the functions to set the current limiting conditions 
 * in order to provide the threshold of the fault conditions.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of I2C module and log UART.
 * After driver initialization, default settings turn on the device.
 *
 * ## Application Task
 * This example demonstrates the use of the Current Limit 7 Click board™.
 * Reading user's input from Usart Terminal and using it as an index 
 * for an array of pre-calculated values that define the current limit level.
 * Results are being sent to the Usart Terminal, where you can track their changes.
 *
 * ## Additional Function
 * - static void display_selection ( void )
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "currentlimit7.h"

static currentlimit7_t currentlimit7;
static log_t logger;

// #define CURRENTLIMIT_MODE_250_mA_500_mA
#define CURRENTLIMIT_MODE_500_mA_2500_mA

const uint16_t limit_value_op[ 14 ] = 
{ 
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_510_mA, 
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_625_mA, 
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_860_mA, 
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_1320_mA, 
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_1450_mA,
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_1550_mA,
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_1750_mA,
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_2020_mA,
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_2260_mA,
    CURRENTLIMIT7_OP_1_CURRENT_LIMIT_2500_mA,
    CURRENTLIMIT7_OP_0_CURRENT_LIMIT_260_mA, 
    CURRENTLIMIT7_OP_0_CURRENT_LIMIT_280_mA, 
    CURRENTLIMIT7_OP_0_CURRENT_LIMIT_330_mA, 
    CURRENTLIMIT7_OP_0_CURRENT_LIMIT_450_mA
};

static void display_selection ( void ) 
{
    log_printf( &logger, "  To select current limit  \r\n" );
    log_printf( &logger, "  Send one of the numbers: \r\n" );
    log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
#ifdef CURRENTLIMIT_MODE_250_mA_500_mA
    log_printf( &logger, "  '0' - Limited to 260 mA  \r\n" );
    log_printf( &logger, "  '1' - Limited to 280 mA  \r\n" );
    log_printf( &logger, "  '2' - Limited to 330 mA  \r\n" );
    log_printf( &logger, "  '3' - Limited to 450 mA  \r\n" );
#else
    log_printf( &logger, " '0' - Limited to  510 mA  \r\n" );
    log_printf( &logger, " '1' - Limited to  625 mA  \r\n" );
    log_printf( &logger, " '2' - Limited to  860 mA  \r\n" );
    log_printf( &logger, " '3' - Limited to 1320 mA  \r\n" );
    log_printf( &logger, " '4' - Limited to 1450 mA  \r\n" );
    log_printf( &logger, " '5' - Limited to 1550 mA  \r\n" );
    log_printf( &logger, " '6' - Limited to 1750 mA  \r\n" );
    log_printf( &logger, " '7' - Limited to 2020 mA  \r\n" );
    log_printf( &logger, " '8' - Limited to 2260 mA  \r\n" );
    log_printf( &logger, " '9' - Limited to 2500 mA  \r\n" );
#endif        
    log_printf( &logger, "---------------------------\r\n" );
}

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    currentlimit7_cfg_t currentlimit7_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.
    currentlimit7_cfg_setup( &currentlimit7_cfg );
    CURRENTLIMIT7_MAP_MIKROBUS( currentlimit7_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == currentlimit7_init( &currentlimit7, &currentlimit7_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( CURRENTLIMIT7_ERROR == currentlimit7_default_cfg ( &currentlimit7 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
    Delay_ms( 100 );
    
    log_info( &logger, " Application Task " );
    log_printf( &logger, "---------------------------\r\n" );
    log_printf( &logger, "   Current Limit 7 Click   \r\n" );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms( 100 );
    
#ifdef CURRENTLIMIT_MODE_250_mA_500_mA
    currentlimit7_set_current_limit ( &currentlimit7, CURRENTLIMIT7_OP_MODE_250_mA_500_mA, limit_value_op[ 10 ] );
    log_printf( &logger, "  >>> Selected mode %d     \r\n", 0 );
    log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
    log_printf( &logger, " Current limit is %d mA    \r\n", limit_value_op[ 10 ] );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms( 100 );
#else
    currentlimit7_set_current_limit ( &currentlimit7, CURRENTLIMIT7_OP_MODE_500_mA_2500_mA, limit_value_op[ 0 ] );
    log_printf( &logger, "  >>> Selected mode %d     \r\n", 0 );
    log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
    log_printf( &logger, " Current limit is %d mA    \r\n", limit_value_op[ 0 ] );
    log_printf( &logger, "---------------------------\r\n" );
    Delay_ms( 100 );
#endif
    
    display_selection( );
    Delay_ms( 100 );
}

void application_task ( void ) 
{
    static char index;
    
    if ( CURRENTLIMIT7_ERROR != log_read( &logger, &index, 1 ) ) 
    {
    #ifdef CURRENTLIMIT_MODE_250_mA_500_mA
        if ( ( index >= '0' ) && ( index <= '3' ) )
        {
            currentlimit7_set_current_limit ( &currentlimit7, CURRENTLIMIT7_OP_MODE_250_mA_500_mA, limit_value_op[ index - 38 ] );
            log_printf( &logger, "  >>> Selected mode %d     \r\n", index - 48 );
            log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
            log_printf( &logger, "  Current limit is %d mA   \r\n", limit_value_op[ index - 38 ] );
            log_printf( &logger, "---------------------------\r\n" );
            Delay_ms( 100 );
        }
    #else
        if ( ( index >= '0' ) && ( index <= '9' ) ) 
        {
            currentlimit7_set_current_limit ( &currentlimit7, CURRENTLIMIT7_OP_MODE_500_mA_2500_mA, limit_value_op[ index - 48 ] );
            log_printf( &logger, "  >>> Selected mode %d     \r\n", index - 48 );
            log_printf( &logger, "- - - - - - - - - - - - - -\r\n" );
            log_printf( &logger, "  Current limit is %d mA   \r\n", limit_value_op[ index - 48 ] );
            log_printf( &logger, "---------------------------\r\n" );
            Delay_ms( 100 );
        }
    #endif
        else 
        { 
            log_printf( &logger, "    Data not in range!    \r\n" );
            log_printf( &logger, "---------------------------\r\n" );
            display_selection( );
            Delay_ms( 100 );
        }
    }
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

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

Additional Support

Resources

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