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Elevate your temperature monitoring game with MCP9800 and PIC18LF45K42

Heat up your efficiency

Thermo 7 Click with EasyPIC v8

Published Nov 07, 2023

Click board™

Thermo 7 Click

Development board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18LF45K42

Unlock the power of temperature data with our solution, enabling data-driven decisions that drive your success

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Hardware Overview

How does it work?

Thermo 7 Click is based on the MCP9800, a high-accuracy temperature sensor IC with the 2-Wire interface, from Microchip. The Click board™ itself has a reasonably small number of components because most of the measurement circuitry is already integrated on the MCP9800 sensor. The I2C / SMBus compatible serial interface lines, along with the ALERT pin, which also works in the open drain configuration, are pulled up by the onboard resistors. The 2-Wire lines are routed to the respective I2C lines of the mikroBUS™ (SCK and SDA), while the ALERT pin is routed to the INT pin of the mikroBUS™. The sensor IC uses the I2C/SMBus compatible communication interface. There are four registers, used to set the temperature limit, temperature hysteresis for the interrupt events, configuration register used to store all the working parameters, and the read-only register which holds the sampled temperature data. More information about all the registers can be found in the MCP9800 datasheet. However, provided library contains functions that simplify the use of the Thermo 7 click. The included application example demonstrates their functionality and it can be used as a reference for custom design. An analog signal from the thermal sensor is sampled by the sigma-delta ADC converter, with the selectable resolution of 9, 10, 11 and 12 bits. The sampling resolution affects the temperature step sizes, as well as the time

required to complete the conversion. The step sizes vary between the 0.5°C with 30ms of conversion time for 9bit sampling, and 0.0625°C with 240ms of conversion time for 12bit resolution. The selectable resolution allows a compromise to be made between the resolution and the conversion time, depending on the application requirements. The ALERT pin is used to trigger an interrupt event on the host MCU. This pin has a programmable polarity: it can be set to be asserted either to a HIGH logic level or to a LOW logic level. Since the Click board™ features a pull-up resistor, it is advised to set the polarity so that the asserted state drives the pin to a LOW logic level. A special mechanism is employed to reduce false ALERT triggering. This mechanism includes queueing of the cycles in which the temperature limit is exceeded. As already described, the ALERT pin is routed to the INT pin of the mikroBUS™. The ALERT pin can be set to work in two different modes: Comparator mode and Interrupt mode. When working in the Comparator mode, this pin will be triggered whenever a temperature limit is exceeded. The ALERT pin stays asserted until the temperature drops below the hysteresis level. Both values are set in the respective temperature registers (limit and hysteresis). This mode is useful for thermostat-like applications: it can be used to power down a system in case of overheating or turn off the cooling fan if the temperature is low

enough. If set to work in the Interrupt mode, the ALERT pin will stay asserted after exceeding the temperature limit, until any internal register is read. When the temperature drops below the hysteresis level, the ALERT pin will be asserted again, waiting for the internal registers to be read once again. This mode is used to trigger an interrupt on the host MCU, which is supposed to read the sensor when the interrupt event is generated. The device can be set to work in several different power modes. It can be set to continuously sample the temperature measurements, it can be set to work in the one-shot mode, and it can be set to stay in the shutdown mode. The shutdown mode consumes the least power, keeping all the internal sections but the communication section, unpowered. The one-shot mode allows the device to stay in the shutdown mode, run a single conversion cycle on demand, and the revert back to the shutdown mode. This allows for a lower power consumption. The design of the Click board™ itself is such that the thermal radiation from other components, which might affect the environmental temperature readings of the sensor, is reduced. The onboard SMD jumper labeled as VCC SEL allows voltage selection for interfacing with both 3.3V and 5V MCUs.

Thermo 7 Click hardware overview image

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. 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, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board 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 DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC 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.

EasyPIC v8 horizontal image

Microcontroller Overview

MCU Card / MCU

PIC18LF45K42

Architecture

PIC

MCU Memory (KB)

32

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

2048

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
NC
NC
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt
RB0
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
Power Supply
5V
5V
Ground
GND
GND
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Take a closer look

Schematic

Thermo 7 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

EasyPIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
MCU DIP 40 hardware assembly
EasyPIC v8 DIP 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 DIP 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 Thermo 7 Click driver.

Key functions:

  • thermo7_get_hysteresis_temperature - This fuction gets Hysteresis Temperature.

  • thermo7_set_limit_temperature - This fuction sets limit temperature.

  • thermo7_get_interrupt - This fuction reads state of interrupt pins.

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 Thermo7 Click example
 * 
 * # Description
 * This application reads ambient temperature.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes device.
 * 
 * ## Application Task  
 * Reads ambient temperature and logs to USBUART every 1 seconds.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "thermo7.h"

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

static thermo7_t thermo7;
static log_t logger;

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

void application_init ( void )
{
    log_cfg_t log_cfg;
    thermo7_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.

    thermo7_cfg_setup( &cfg );
    THERMO7_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    thermo7_init( &thermo7, &cfg );

    thermo7_set_configuration( &thermo7, THERMO7_CONFIG_COMPARATOR_MODE | THERMO7_CONFIG_ALERT_POLARITY_ACTIVE_HIGH );
    thermo7_set_resolution( &thermo7, THERMO7_CONFIG_ADC_RESOLUTION_12bit );
}

void application_task ( void )
{
    float ambient_temperature;

    ambient_temperature = thermo7_read_ambient_temperature( &thermo7 );
    log_printf( &logger, " Ambient temperature : %f C\r\n", ambient_temperature 
);

    Delay_ms( 1000 );
}

void main ( void )
{
    application_init( );

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

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

Additional Support

Resources