Create a reliable and innovative current limiting solution with MAX890L and TM4C129ENCPDT

Redefining safety and efficiency: The future of current limiting

Current Limit Click with Fusion for Tiva v8

Published Oct 10, 2023

Click board™

Current Limit Click

Dev. board

Fusion for Tiva v8

Compiler

NECTO Studio

MCU

TM4C129ENCPDT

Our current limiting solution is engineered to transform control mechanisms, ensuring that current is managed effectively to optimize performance, protect equipment, and enhance safety

Hardware Overview

How does it work?

Current Limit Click is based on the MAX890L, a high-side low-resistance P-channel switch with an adjustable, accurate, current limit system and thermal shutdown from Analog Devices. The MAX890L limits the output current to a programmed level. When the output current is increased beyond the programmed current limit (1.2A), the current increases through the internal replica amplifier and the resistance applied to the SET pin. The current-limit error amplifier compares the voltage across the SET pin resistance to the internal +1.24V reference and regulates the current back to the lesser of the programmed limit (1.2A). This switch is not bidirectional, which means the input voltage must be higher than the output voltage. The current-limit switch is virtually

ubiquitous in system control and 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. Replacing the resistor with a digital potentiometer allows you to program the current limit as performed on this Click board™. For this purpose, the digital potentiometer MAX5401 from Analog Devices that communicates with the MCU via a 3-wire SPI serial interface is used to set the resistance on the SET pin of the MAX890L and thus adjust the current limit for the switch. The MAX890L provides an open-drain fault output

with a red LED, labeled FAULT, to indicate when the current reaches its limit or when the temperature exceeds +135°C. Besides the fault-indicator pin, the MAX890L also has an active-low Switch-On pin labeled ON pin of the mikroBUS™ socket used to enable and turn the switch on. This Click board™ is designed to operate with 3.3V and 5V logic voltage levels that can be selected via the VCC SEL jumper. Additionally, there is a possibility in this selection that as a source of logical voltage level, a voltage from an external input terminal in the range from 2.7 to 5.5V can be used. In this way, using a logic voltage level from mikroBUS™ or an external voltage supply allows both 3.3V and 5V capable MCUs to use the SPI communication lines properly.

Current Limit Click hardware overview image

Features overview

Development board

Fusion for TIVA v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from Texas Instruments, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over a WiFi network. 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, Fusion for TIVA v8 provides a fluid and immersive working experience, allowing access

anywhere and under any circumstances at any time. Each part of the Fusion for TIVA v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it 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 HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for TIVA 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.

Microcontroller Overview

MCU Card / MCU

Type

8th Generation

Architecture

ARM Cortex-M4

MCU Memory (KB)

1024

Silicon Vendor

Texas Instruments

Pin count

128

RAM (Bytes)

262144

Used MCU Pins

mikroBUS™ mapper

Switch Enable

PD0

RST

SPI Chip Select

PH0

SPI Clock

PQ0

SCK

MISO

SPI Data IN

PQ2

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

Fusion for PIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the Fusion for Tiva v8 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

GNSS2 Click front image hardware assembly

SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly

GNSS2 Click complete accessories setup image hardware assembly

Board mapper by product7 hardware assembly

NECTO Compiler Selection Step 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 Click driver.

Key functions:

currentlimit_dev_enable - Device enable function
currentlimit_set_limit - Set Current With Predefined Values Limit function
currentlimit_set_limit_calc - Set Calculated Current Limit 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 CurrentLimit Click example
 *
 * # Description
 * This example shows capabilities of Current Limit Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initalizes SPI driver and enables the device.
 *
 * ## Application Task
 * Reading users input from USART terminal and using it as an index for
 * an array of pre-calculated values that define current limit level.
 *
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "currentlimit.h"

static currentlimit_t currentlimit;
static log_t logger;

const uint8_t lim_val[ 8 ] = { 223, 241, 247, 250, 252, 253, 254, 255 };
uint16_t lim_data[8] = { 100, 200, 300, 400, 500, 600, 700, 867 };

void display_settings ( void ) {
    log_printf( &logger, "- - - - - - - - - - - - - - - \r\n" );
    log_printf( &logger, " To select current limit \r\n" );
    log_printf( &logger, " Send one of the numbers \r\n" );
    log_printf( &logger, "- - - - - - - - - - - - - - - \r\n" );
    log_printf( &logger, " 1 - Limited to 100 mA \r\n" );
    log_printf( &logger, " 2 - Limited to 200 mA \r\n" );
    log_printf( &logger, " 3 - Limited to 300 mA \r\n" );
    log_printf( &logger, " 4 - Limited to 400 mA \r\n" );
    log_printf( &logger, " 5 - Limited to 500 mA \r\n" );
    log_printf( &logger, " 6 - Limited to 600 mA \r\n" );
    log_printf( &logger, " 7 - Limited to 700 mA \r\n" );
    log_printf( &logger, " 8 - Limited to 867 mA \r\n" );
    log_printf( &logger, "- - - - - - - - - - - - - - - \r\n" );
}

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    currentlimit_cfg_t currentlimit_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.

    currentlimit_cfg_setup( &currentlimit_cfg );
    CURRENTLIMIT_MAP_MIKROBUS( currentlimit_cfg, MIKROBUS_1 );
    err_t init_flag  = currentlimit_init( &currentlimit, &currentlimit_cfg );
    if ( SPI_MASTER_ERROR == init_flag ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    currentlimit_dev_enable( &currentlimit, CURRENTLIMIT_ENABLE );
    log_printf( &logger, "    Click  Enabled!    \r\n" );
    log_printf( &logger, "-----------------------\r\n" );
    Delay_ms ( 100 );
    log_info( &logger, " Application Task " );
    display_settings( );
}

void application_task ( void ) {
    char inx;
    if ( log_read( &logger, &inx, 1 ) != CURRENTLIMIT_ERROR ) {
        if ( inx >= '1' && inx <= '8' ) {
            currentlimit_set_limit( &currentlimit, lim_val[ inx - 49 ] );
            log_printf( &logger, " Selected mode %d, \r\n Current limit is %d mA \r\n", ( uint16_t ) inx - 48, lim_data[ inx - 49 ] );
            log_printf( &logger, "- - - - - - - - - - - - - - - \r\n" );
        } else { 
            log_printf( &logger, "- - - - - - - - - - - - - - - \r\n" );
            log_printf( &logger, " Data not in range! \r\n" );
            log_printf( &logger, "- - - - - - - - - - - - - - - \r\n" );
            display_settings( );
        }
    }
}

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