Measure temperature and humidity easily with SHT41A and dsPIC33FJ256GP710A

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Published Mar 11, 2023

Click board™

Temp&Hum 22 Click

Dev. board

UNI-DS v8

Compiler

NECTO Studio

MCU

dsPIC33FJ256GP710A

Reliable temperature and humidity data, even in the most challenging conditions

Hardware Overview

How does it work?

Temp&Hum 22 Click is based on the SHT41A, high-accuracy automotive-grade 16-bit relative humidity and temperature sensor from Sensirion. The SHT41A builds on a wholly new and optimized CMOS chip, offering reduced power consumption, accuracy, and a digital I2C interface for the fastest data transfer. It covers extended operating humidity, and temperature ranges from 0 to 100%RH and from -40°C to 125°C with accuracies of ±1%RH and ±0.3°C. The SHT41A's integrated heater allows advanced on-board-diagnostics alongside reliable operation in harsh conditions such as condensing environments.

The sensor performs best when operated within the recommended average temperature and humidity range of 5-60°C and 20-80%RH. Long-term exposure to conditions outside recommended normal range, especially at high relative humidity, may temporarily offset the RH signal. After returning to the recommended average temperature and humidity range, the sensor will recover to within specifications. Also, to maximize the over-temperature when using the heater, reduced heat conduction and heat capacity of the mounted sensor is desired. For this reason, the sensor is placed on this Click board™ in a particular

position, a piece of a standard PCB with a cutout around the sensor area, increasing the decontamination yield and avoiding excess energy consumption. A PCB layout like this is optimized for minimal thermal heat sink influence. This Click board™ can only be operated with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ 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

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

dsPIC

MCU Memory (KB)

256

Silicon Vendor

Microchip

Pin count

100

RAM (Bytes)

30720

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

INT

I2C Clock

RA2

SCL

I2C Data

RA3

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ 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

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 Temp&Hum 22 Click driver.

Key functions:

temphum22_soft_reset This function performs the software reset by sending the soft reset command.
temphum22_read_serial_num This function reads the 4-bytes unique serial number by using I2C serial interface.
temphum22_read_measurement_high_precision This function reads the temperature and humidity measurements with high precision.

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 TempHum 22 Click example
 *
 * # Description
 * This example demonstrates the use of Temp & Hum 22 click board by reading
 * the temperature and humidity data.
 * 
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver, performs the sensor software reset and then reads
 * and displays the sensor unique serial number.
 *
 * ## Application Task
 * Reads the temperature (degC) and the relative humidity (%RH) data and 
 * displays the results on the USB UART approximately once per second.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "temphum22.h"

static temphum22_t temphum22;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    temphum22_cfg_t temphum22_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.
    temphum22_cfg_setup( &temphum22_cfg );
    TEMPHUM22_MAP_MIKROBUS( temphum22_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == temphum22_init( &temphum22, &temphum22_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( TEMPHUM22_OK == temphum22_soft_reset ( &temphum22 ) )
    {
        log_printf ( &logger, " Software reset\r\n" );
    }
    Delay_1sec ( );
    
    uint32_t serial_num;
    if ( TEMPHUM22_OK == temphum22_read_serial_num ( &temphum22, &serial_num ) )
    {
        log_printf ( &logger, " Serial number: 0x%.8LX\r\n", serial_num );
    }
    
    log_info( &logger, " Application Task " );
}

void application_task ( void ) 
{
    float temperature, humidity;
    if ( TEMPHUM22_OK == temphum22_read_measurement_high_precision ( &temphum22, &temperature, &humidity ) )
    {
        log_printf ( &logger, " Temperature: %.2f degC\r\n", temperature );
        log_printf ( &logger, " Humidity: %.2f %%RH\r\n\n", humidity );
        Delay_ms ( 1000 );
    }
}

void main ( void ) 
{
    application_init( );

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

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