Experience the future of temperature measurement with MAX31875 and PIC32MX664F064L

Precision in every degree

Published Nov 07, 2023

Click board™

Thermo 6 Click

Dev Board

UNI-DS v8

Compiler

NECTO Studio

MCU

PIC32MX664F064L

We empower you with real-time temperature data to make informed decisions and keep your environment at the perfect temperature

Hardware Overview

How does it work?

Thermo 6 Click is based on the MAX31875, a temperature sensor from Analog Devices, which has only four connections, two of which are used for the power supply and the other two are the standard I2C interface lines: SDA and SCL. The normal transaction consists of two bytes long reads and writes as the registers are 16 bits wide. There are 8 different factory predefined I2C addresses, so the exact sensor I2C address can be determined by checking the part I2C address table in the datasheet. The sensor is exposed on a specially designed PCB, so the measurement of the ambient temperature can remain accurate and without interference. Sensor measures its die temperature and converts the thermal measurement into a digital information, which can be accessed via the I2C/SMBus interface. Information is stored in the temperature register, in MSB - LSB format. In addition to the normal

temperature data format, there is an optional extended data format, which allows temperatures greater than +128 C to be read. The temperature format and other sensor settings can be configured via the configuration registers. Check the MAX31875 datasheet for more detailed information. All of the power down, standby, read and write commands are intelligently managed, so the device is waiting for the pending communication to be completed, before executing those commands. Also, while reading the thermal data, the conversion process is halted, so the value won't change before the reading is completed. The MAX31875 temperature sensor can be set to sample the thermal data with 8bit, 9bit, 10bit and 12bit resolution. Using the higher precision conversion directly affects the power consumption, so if there is a demand for the low power application, resolution can be set down to

8bit. Power consumption can be reduced even further, by using the lower sample rate, which results in longer idle periods. While idling, the power consumption of the sensor itself goes down to 500 nA. One shot reading allows for the lowest power consumption - down to 5uA, if there is no demand for continuous temperature conversion. The device remains in standby state, as long as there is no read command. Read command (writing 1 to the bit 0 of the config register) will wake up the device and read the temperature data immediately, after which it will revert to standby mode again. This allows for a very low average power consumption. Other advanced features such as the PEC, I2C bus timeout reset, temperature comparator, can also be configured by setting the corresponding bits of the config registers.

Features overview

Development board

UNI-DS 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 STM32, Kinetis, TIVA, CEC, MSP, PIC, dsPIC, PIC32, and AVR MCUs regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over WiFi. 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, UNI-DS v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the UNI-DS 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. UNI-DS 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

PIC32

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

32768

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

PA2

SCL

I2C Data

PA3

SDA

Ground

GND

Take a closer look

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 UNI-DS 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.

Buck 22 Click front image hardware assembly

SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly

v8 SiBRAIN MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Track your results in real time

Application Output

After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.

Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.

In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".

The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

Software Support

Library Description

This library contains API for Thermo 6 Click driver.

Key functions:

thermo6_get_temperature_data - Temperature function
thermo6_get_over_temp_status - Read over-temperature status function
thermo6_get_other_register - Set other register

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 Thermo6 Click example
 * 
 * # Description
 * Demo application shows ambient temperature reading using Thermo 6 click.
 * 
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Configuring clicks and log objects.
 * Setting the click in the default configuration to start the measurement.
 * 
 * ## Application Task  
 *  It measures the temperature and logs a message about the current temperature.
 * 
 * \author Katarina Perendic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "thermo6.h"

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

static thermo6_t thermo6;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    thermo6_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.

    thermo6_cfg_setup( &cfg );
    THERMO6_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    thermo6_init( &thermo6, &cfg );

    thermo6_default_cfg( &thermo6 );
    log_info( &logger, "---- Start measurement ----");
    Delay_ms( 1000 );
}

void application_task ( void )
{
    float temperature;

    //  Task implementation.

    temperature = thermo6_get_temperature_data( &thermo6, THERMO6_TEMP_FORMAT_CELSIUS );
    log_printf( &logger, ">> Temperature is %.3f C \r\n", temperature );

    Delay_ms( 1000 );
}

void main ( void )
{
    application_init( );

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


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