10 min

Achieve unmatched accuracy and reliability in temperature measurement with MAX31865 and STM32F101ZG

Your partner for ultra-precise temperature monitoring!

RTD Click with Fusion for ARM v8

Published Nov 07, 2023

Click board™

RTD Click


Fusion for ARM v8


NECTO Studio



Mastery of temperature control begins with our RTD solution, meticulously crafted for PT100 platinum probes, setting a new benchmark in precision.



Hardware Overview

How does it work?

RTD Click is based on the MAX31865, a resistance to digital converter from Analog Devices, optimized for platinum resistance temperature detectors, or RTD. The click uses the PT100 type platinum probe for temperature measurement. There are four screw terminals on the board, so different PT100 probe types can be used with this design. This click board™ can work with 2, 3 or 4-wire PT100 probe types. RTD probes are

commonly used to measure a range of temperatures between −200°C and 500°C, but the exact value depends on the specific probes used. Features like the 15bit ADC resolution, input terminals overvoltage protection up to ±45V, fault detection, a fast response time of 21mS and the SPI interface, make the RTD click an ideal solution when it comes to the precise measuring of extremely high and low temperatures. This Click

board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

RTD Click top side image
RTD Click bottom side image

Features overview

Development board

Fusion for ARM 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 ARM® Cortex®-M based 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, Fusion for ARM v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the Fusion for ARM 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 ARM 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.

Fusion for ARM v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M3

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


You complete me!


The PT100 3-wire temperature probe is an advanced RTD platinum sensor designed for precise temperature measurement up to 250°C. Perfectly compatible with the RTD Click board™, this probe utilizes RTD sensors - thermosensitive resistors that adapt their resistance to temperature changes. The probe's core features a meticulously crafted strip of platinum with a resistance of 100Ω at 0°C, earning the designation PT100. Key features include a temperature range of up to 250⁰ Celsius, a 3-wire configuration for enhanced accuracy, a length of 1m (100cm, 3.37 inches), Grade 2B construction for durability, and a tight tolerance of 0.5". Whether in industrial or scientific settings, the PT100 3-wire temperature probe delivers reliable and precise temperature readings, ensuring optimal performance in diverse applications.

RTD Click accessories image

Used MCU Pins

mikroBUS™ mapper

SPI Chip Select
SPI Slock
Power Supply

Take a closer look


RTD Click Schematic 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 ARM v8 as your development board.

Fusion for PIC v8 front image hardware assembly
GNSS2 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
GNSS2 Click complete accessories setup image hardware assembly
v8 SiBRAIN 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 Compiler Selection Step Image hardware assembly
NECTO Output Selection Step Image hardware assembly
Necto image step 6 hardware assembly
Necto 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

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.

UART Application Output Step 1

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.

UART Application Output Step 2

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".

UART Application Output Step 3

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.

UART Application Output Step 4

Software Support

Library Description

This library contains API for RTD Click driver.

Key functions:

  • rtd_read_register - This function reads data from the chosen register.

  • rtd_read_temperature - This function reads data from temperature registers.

  • rtd_convert_temperature - This function convert data from temperature registers.

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 Rtd Click example
 * # Description
 * This app measures temperature and converts the data to celsius degrees.
 * The demo application is composed of two sections :
 * ## Application Init 
 * Initializes RTD click driver, and sets the
 * proper configuration mode for three wire RTD.
 * ## Application Task  
 * Measures temperature, converts the data to celsius degrees,
 * and outputs them via UART.
 * \author MikroE Team
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "rtd.h"

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

static rtd_t rtd;
static log_t logger;

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

void application_init ( void )
    log_cfg_t log_cfg;
    rtd_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.

    rtd_cfg_setup( &cfg );
    rtd_init( &rtd, &cfg );

    rtd_write_register( &rtd, RTD_CONFIGURATION, 0xD0 );

void application_task ( void )
    uint16_t read_value;
    float converted_value;

    read_value = rtd_read_temperature( &rtd );
    converted_value = rtd_convert_temperature( &rtd, read_value, RTD_REF_RESISTANCE_470);

    log_printf( &logger, "Current temperature: %.2f \r\n", converted_value );

    Delay_ms( 300 );

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support