30 min

Measure air pressure quickly using ICP-20100 and STM32F439ZG

Keeping the air in check

Pressure 20 Click with UNI-DS v8

Published Mar 07, 2023

Click board™

Pressure 20 Click

Development board



NECTO Studio



Monitor atmospheric pressure changes anywhere



Hardware Overview

How does it work?

Pressure 20 Click is based on the ICP-20100, a high accuracy, low power, barometric pressure, and temperature sensor solution from TDK InvenSense. It integrates a capacitive pressure sensor for monitoring pressure changes from 30kPa to 110kPa with an accuracy of ±20Pa over a wide operating temperature range. The ICP-20100 achieves the industry's lowest pressure noise of 0.4Pa RMS while attaining the industry's lowest power consumption and retains excellent temperature stability with a temperature coefficient of ±0.4Pa/°C. This MEMS sensor consists of a capacitive pressure sensor whose capacitance changes according to the pressure applied. An integrated temperature sensor on the same MEMS

sensor allows accurate temperature measurements. Other industry-leading features include 20-bit output data, programmable digital filters, calibration, FIFO, and programmable interrupts. Pressure 20 Click allows using I2C and SPI interfaces with a maximum frequency of 1MHz for I2C and 12MHz for SPI communication. The selection can be made by positioning SMD jumpers labeled as COMM SEL in an appropriate position. Note that all the jumpers' positions must be on the same side, or the Click board™ may become unresponsive. While the I2C interface is selected, the ICP-20100 allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled ADDR SEL.

This Click board™ also possesses an additional interrupt pin, routed to the INT pin on the mikroBUS™ socket, indicating when a specific interrupt event occurs, such as FIFO overflow/underflow, the threshold over/underrun, and more. This Click board™ can only be operated from a 3.3V logic voltage level. Therefore, the board must perform appropriate logic voltage 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.

Pressure 20 Click top side image
Pressure 20 Click lateral side image
Pressure 20 Click bottom side image

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.

UNI-DS v8 horizontal image

Microcontroller Overview

MCU Card / MCU



8th Generation


ARM Cortex-M4

MCU Memory (KB)


Silicon Vendor


Pin count


RAM (Bytes)


Used MCU Pins

mikroBUS™ mapper

SPI Chip Select
SPI Clock
Power Supply
I2C Clock
I2C Data

Take a closer look


Pressure 20 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 UNI-DS v8 as your development board.

Fusion for PIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
SiBRAIN for PIC32MZ1024EFK144 front image hardware assembly
v8 SiBRAIN 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 Pressure 20 Click driver.

Key functions:

  • pressure20_get_int_pin This function returns the INT pin logic state.

  • pressure20_clear_interrupts This function reads and clears the interrupt status register.

  • pressure20_read_data This function reads the pressure [mBar] and temperature [Celsius] data.

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 main.c
 * @brief Pressure20 Click example
 * # Description
 * This example demonstrates the use of Pressure 20 click board by reading and displaying
 * the pressure and temperature data on the USB UART.
 * The demo application is composed of two sections :
 * ## Application Init
 * Initializes the driver and performs the click default configuration.
 * ## Application Task
 * Waits for the data ready interrupt, clears the interrupts and than reads 
 * the pressure [mBar] and temperature [Celsius] data and displays them on the USB UART 
 * at the set output data rate (25Hz by default).
 * @author Stefan Filipovic

#include "board.h"
#include "log.h"
#include "pressure20.h"

static pressure20_t pressure20;
static log_t logger;

void application_init ( void )
    log_cfg_t log_cfg;  /**< Logger config object. */
    pressure20_cfg_t pressure20_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.
    pressure20_cfg_setup( &pressure20_cfg );
    PRESSURE20_MAP_MIKROBUS( pressure20_cfg, MIKROBUS_1 );
    err_t init_flag  = pressure20_init( &pressure20, &pressure20_cfg );
    if ( ( I2C_MASTER_ERROR == init_flag ) || ( SPI_MASTER_ERROR == init_flag ) )
        log_error( &logger, " Communication init." );
        for ( ; ; );
    if ( PRESSURE20_ERROR == pressure20_default_cfg ( &pressure20 ) )
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    log_info( &logger, " Application Task " );

void application_task ( void )
    // Wait for the data ready interrupt
    while ( pressure20_get_int_pin ( &pressure20 ) );
    float pressure, temperature;
    if ( ( PRESSURE20_OK == pressure20_clear_interrupts ( &pressure20 ) ) &&
         ( PRESSURE20_OK == pressure20_read_data ( &pressure20, &pressure, &temperature ) ) )
        log_printf ( &logger, " Pressure: %.1f mBar\r\n", pressure );
        log_printf ( &logger, " Temperature: %.2f C\r\n\n", temperature );

void main ( void )
    application_init( );

    for ( ; ; )
        application_task( );

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

Additional Support