Master VCT monitoring with LTC2990 and ATmega1284P

TempVoltCurrent insight

Published Nov 01, 2023

Click board™

VCT Monitor Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega1284P

Track real-time temperature, voltage, and current easily for issue detection and operational optimization

Hardware Overview

How does it work?

VCT Monitor Click is based on the LTC2990, a high-performance temperature, voltage, and current monitor with the I2C serial interface from Analog Devices. The LTC2990 can be configured to measure many combinations of internal temperature, remote temperature, remote voltage or current, and internal VCC with single or repeated measurements. It fits in systems needing sub-millivolt voltage resolution, 1% current measurement, and 1°C temperature accuracy or any combination. The input signals are selected with an input MUX, controlled by the control logic

block. The control logic uses the mode bits in the control register to manage the sequence and types of data acquisition. The control logic also controls the variable current sources during remote temperature acquisition. The ADC performs the necessary conversion(s) and supplies the data to the control logic for further processing for temperature measurements or routing to the appropriate data register for voltage and current measurements. Remote measurements are performed on terminals labeled as TEMP and LOAD using multiple ADC conversions and source

currents to compensate for sensor series resistance. The LTC2990 is calibrated to yield the correct temperature for a remote diode with an ideality factor of 1.004. 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.

VCT Monitor Click hardware overview image

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 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

Architecture

AVR

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

PC0

SCL

I2C Data

PC1

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 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

GNSS2 Click complete accessories setup image hardware assembly

EasyAVR v7 Access DIP MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection 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 VCT Monitor Click driver.

Key functions:

vctmonitor_get_status - Gets status value
vctmonitor_read_temperature - Get temperature function
vctmonitor_read_current - Current 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 VCTMonitor Click example
 *
 * # Description
 * This is an example which demonstrates the use of VCT Monitor Click board.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization driver enables the USB uart terminal and I2C.  
 *
 * ## Application Task
 * Reads temperature, current value, and differential voltage every 4 seconds.
 *
 * @note
 * The click has been tested using the following:
 *       - Power supply - 4V
 *       - Current (Load) - 0A to 3A
 *       - External MMBT3904 temperature sensor
 *
 * @author Stefan Ilic
 *
 */

#include "board.h"
#include "log.h"
#include "vctmonitor.h"

static vctmonitor_t vctmonitor;
static log_t logger;

void application_init ( void ) {
    log_cfg_t log_cfg;  /**< Logger config object. */
    vctmonitor_cfg_t vctmonitor_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.
    vctmonitor_cfg_setup( &vctmonitor_cfg );
    VCTMONITOR_MAP_MIKROBUS( vctmonitor_cfg, MIKROBUS_1 );
    err_t init_flag = vctmonitor_init( &vctmonitor, &vctmonitor_cfg );
    if ( I2C_MASTER_ERROR == init_flag ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    log_info( &logger, " Application Task " );
}

void application_task ( void ) {
    float temperature;
    float voltage;
    float current;

    voltage = vctmonitor_read_voltage_differential( &vctmonitor );
    log_printf( &logger, " Voltage    : %.2f mV \r\n", voltage );

    current = vctmonitor_read_current( &vctmonitor );
    log_printf( &logger, " Current    : %.2f mA \r\n", current );

    temperature = vctmonitor_read_temperature( &vctmonitor );
    log_printf( &logger, " Temperature: %.2f C \r\n", temperature );

    log_printf( &logger, "- - - - - - - - - - - -\r\n" );
    Delay_ms( 4000 );     
}

void main ( void ) {
    application_init( );

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

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