Experience the ideal temperature in your surroundings with TMP126 and PIC18F2455

Transform your temperature monitoring approach!

Published Dec 29, 2023

Click board™

Thermo 29 Click

Dev Board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18F2455

We prioritize your well-being by delivering reliable temperature data to help you create a healthier and more cost-effective environment.

Hardware Overview

How does it work?

Thermo 29 Click is based on the TMP126, a digital output temperature sensor from Texas Instruments with increased reliability and improved accuracy specifications optimal for thermal management and protection applications. The TMP126 consists of an internal thermal BJT (factory calibrated on a NIST traceable setup), a high-resolution analog-to-digital converter (ADC), a data processing circuit, and serial interface logic functions in one package. The voltage is digitized and converted to a 14-bit temperature result in degrees Celsius, giving a fully calibrated digital output with outstanding accuracy of up to ±0.25°C and temperature resolution of 0.03125°C per LSB, typical over a temperature range of 20°C to 30°C. This Click

board™ communicates with MCU using a 3-wire SPI-compatible interface with a maximum frequency of 10MHz for data transfer and configuration of the TMP126. Using the Mode bit in the configuration register, the TMP126 can operate in various conversion modes, including continuous, one-shot, and shutdown modes. These modes provide flexibility to use the board in the most power-efficient way necessary for the intended application. The TMP126 also includes advanced features for increased reliability in harsh environments. These include an optional CRC checksum for data integrity, programmable alert limits, a temperature slew rate warning, and an enhanced operating temperature range. An alarm (interrupt) signal, marked as ALR and routed to

the interrupt pin of the mikroBUS™ socket, is alarming when a specific temperature event occurs that depends on the value of the temperature reading relative to programmable limits. In addition to the ALR pin, this function can be visually identified by a red LED marked as ALERT. 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.

Features overview

Development board

EasyPIC v7 is the seventh generation of PIC development boards specially designed to develop embedded applications rapidly. It supports a wide range of 8-bit PIC microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB-B. 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, EasyPIC v7 allows you to connect accessory boards, sensors, and custom electronics more efficiently than ever. Each part of

the EasyPIC 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 various external power sources, including an external 12V power supply, 7-23V AC or 9-32V 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. These sockets cover a wide range of 8-bit PIC MCUs, from PIC10F, PIC12F, PIC16F, PIC16Enh, PIC18F, PIC18FJ, and PIC18FK families. EasyPIC 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

PIC

MCU Memory (KB)

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

RST

SPI Chip Select

RA5

SPI Clock

RC3

SCK

SPI Data OUT

RC4

MISO

SPI Data IN

RC5

MOSI

Power Supply

3.3V

Ground

GND

PWM

Alert Interrupt

RB1

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyPIC v7 front image hardware assembly

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

Rotary B 2 Click front image hardware assembly

EasyPIC v7 MB 2 - 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

This Click board can be interfaced and monitored in two ways:

Application Output - Use the "Application Output" window in Debug mode for real-time data monitoring. Set it up properly by following this tutorial.

UART Terminal - Monitor data via the UART Terminal using a USB to UART converter. For detailed instructions, check out this tutorial.

Software Support

Library Description

This library contains API for Thermo 29 Click driver.

Key functions:

thermo29_read_unique_id - This function reads the device unique ID words (6 bytes in total).
thermo29_get_alert_pin - This function returns the alert pin logic state.
thermo29_read_temperature - This function reads the temperature measurement in degrees Celsius.

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 Thermo 29 Click example
 *
 * # Description
 * This example demonstrates the use of Thermo 29 click board by reading and displaying
 * the temperature measurements.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and logger, and performs the click default configuration which enables
 * continuous conversion and sets the conversion rate to 1 Hz with a data ready flag enabled on
 * the alert pin. After that, reads and displays the device 48-bit unique ID.
 *
 * ## Application Task
 * Waits for the data ready alert flag, then reads the temperature measurement in Celsius
 * and displays the results on the USB UART approximately once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "thermo29.h"

static thermo29_t thermo29;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    thermo29_cfg_t thermo29_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.
    thermo29_cfg_setup( &thermo29_cfg );
    THERMO29_MAP_MIKROBUS( thermo29_cfg, MIKROBUS_1 );
    if ( SPI_MASTER_ERROR == thermo29_init( &thermo29, &thermo29_cfg ) )
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( THERMO29_ERROR == thermo29_default_cfg ( &thermo29 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    uint16_t unique_id[ 3 ];
    if ( THERMO29_OK == thermo29_read_unique_id ( &thermo29, unique_id ) )
    {
        log_printf ( &logger, " Device Unique ID: 0x%.2X%.2X%.2X\r\n", 
                     unique_id[ 0 ], unique_id[ 1 ], unique_id[ 2 ] );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void )
{
    float temperature;
    // Wait for the data ready alert flag
    while ( thermo29_get_alert_pin ( &thermo29 ) );
    
    if ( ( THERMO29_OK == thermo29_clear_alert_status ( &thermo29 ) ) && 
         ( THERMO29_OK == thermo29_read_temperature ( &thermo29, &temperature ) ) )
    {
        log_printf ( &logger, " Temperature: %.2f degC\r\n\n", temperature );
    }
}

void main ( void )
{
    application_init( );

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

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