Achieve unmatched accuracy and reliability in temperature measurement with MAX31865 and ATmega324A
Your partner for ultra-precise temperature monitoring!
Published Jul 11, 2024
Click board™
RTD Click
Dev. board
EasyAVR v8
Compiler
NECTO Studio
MCU
ATmega324A
Mastery of temperature control begins with our RTD solution, meticulously crafted for PT100 platinum probes, setting a new benchmark in precision.
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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.
Features overview
Development board
EasyAVR v8 is a development board designed to rapidly develop embedded applications based on 8-bit AVR microcontrollers (MCUs). Redesigned from the ground up, EasyAVR v8 offers a familiar set of standard features, as well as some new and unique features standard for the 8th generation of development boards: programming and debugging over the WiFi network, connectivity provided by USB-C connectors, support for a wide range of different MCUs, and more. The development board is designed so that the developer has everything that might be needed for the application development, following the Swiss Army knife concept: a highly advanced programmer/debugger module, a reliable power supply module, and a USB-UART connectivity option. EasyAVR v8 board offers several different DIP sockets, covering a wide range of 8-bit AVR MCUs, from the smallest
AVR MCU devices with only eight pins, all the way up to 40-pin "giants". The development board supports the well-established mikroBUS™ connectivity standard, offering five mikroBUS™ sockets, allowing access to a huge base of Click boards™. EasyAVR v8 offers two display options, allowing even the basic 8-bit AVR MCU devices to utilize them and display graphical or textual content. One of them is the 1x20 graphical display connector, compatible with the familiar Graphical Liquid Crystal Display (GLCD) based on the KS108 (or compatible) display driver, and EasyTFT board that contains TFT Color Display MI0283QT-9A, which is driven by ILI9341 display controller, capable of showing advanced graphical content. The other option is the 2x16 character LCD module, a four-bit display module with an embedded character-based display controller. It
requires minimal processing power from the host MCU for its operation. There is a wide range of useful interactive options at the disposal: high-quality buttons with selectable press levels, LEDs, pull-up/pulldown DIP switches, and more. All these features are packed on a single development board, which uses innovative manufacturing technologies, delivering a fluid and immersive working experience. The EasyAVR v8 development board is also integral to the MIKROE rapid development ecosystem. Natively supported by the MIKROE Software toolchain, backed up by hundreds of different Click board™ designs with their number growing daily, it covers many different prototyping and development aspects, thus saving precious development time.
Microcontroller Overview
MCU Card / MCU
Architecture
AVR
MCU Memory (KB)
32
Silicon Vendor
Microchip
Pin count
40
RAM (Bytes)
2048
You complete me!
Accessories
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.
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Click board™ Schematic
Step by step
Project assembly
Start by selecting your development board and Click board™. Begin with the EasyAVR v8 as your development board.
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 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
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
* \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 displays it on the USB 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_MAP_MIKROBUS( cfg, MIKROBUS_1 );
rtd_init( &rtd, &cfg );
RTD_SET_DATA_SAMPLE_EDGE;
rtd_write_register( &rtd, RTD_CONFIGURATION, 0xD0 );
Delay_ms ( 100 );
log_info( &logger, " Application Task " );
}
void application_task ( void )
{
uint16_t read_value = 0;
float converted_value = 0;
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 );
}
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
Additional Support
Resources
Category:Temperature & humidity
