Receive accurate readings of air pressure with LPS25HB and MK64FN1M0VDC12
Your favorite weather forecaster
Published Jun 21, 2023
Click board™
Barometer Click
Dev. board
Clicker 2 for Kinetis
Compiler
NECTO Studio
MCU
MK64FN1M0VDC12
With its ability to detect subtle pressure variations, this solution helps you make informed decisions regarding outdoor activities and travel plans
A
A
Hardware Overview
How does it work?
Barometer Click is based on the LPS25HB, a high-resolution, digital output pressure sensor from STMicroelectronics. The LPS25HB includes a sensing element based on a piezoresistive Wheatstone bridge approach. When pressure is applied, the membrane deflection induces an imbalance in the Wheatstone bridge piezoresistance, whose output signal is converted into a 24-bit digital value by the selectable digital interface. The LPS25HB's interface is factory-calibrated at three temperatures and two pressures for sensitivity and accuracy. The LPS25HB delivers low-pressure noise with low power consumption and operates over an extended temperature range. It has a selectable
absolute pressure range, from 260 up to 1260hPa, with typical absolute pressure and temperature accuracy of ±0.2hPa and ±2°C, ideally suited for various pressure-based applications. Barometer Click allows the use of both I2C and SPI interfaces with a maximum frequency of 400kHz for I2C and 10MHz for SPI communication. The selection can be made by positioning SMD jumpers in an appropriate position marked as I2C or SPI. 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 LPS25HB allows choosing the least significant bit (LSB) of its I2C slave address using the SMD jumper labeled I2C ADR. This Click board™
also possesses an additional interrupt pin, routed to the INT pin on the mikroBUS™ socket labeled as RDY, indicating when a new measured pressure data is available, simplifying data synchronization in digital systems or optimizing system power consumption. 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. 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
Clicker 2 for Kinetis is a compact starter development board that brings the flexibility of add-on Click boards™ to your favorite microcontroller, making it a perfect starter kit for implementing your ideas. It comes with an onboard 32-bit ARM Cortex-M4F microcontroller, the MK64FN1M0VDC12 from NXP Semiconductors, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, LED indicators, buttons, a JTAG programmer connector, and two 26-pin headers for interfacing with external electronics. Its compact design with clear and easily recognizable silkscreen markings allows you to build gadgets with unique functionalities and
features quickly. Each part of the Clicker 2 for Kinetis development kit contains the components necessary for the most efficient operation of the same board. In addition to the possibility of choosing the Clicker 2 for Kinetis programming method, using a USB HID mikroBootloader or an external mikroProg connector for Kinetis programmer, the Clicker 2 board also includes a clean and regulated power supply module for the development kit. It provides two ways of board-powering; through the USB Micro-B cable, where onboard voltage regulators provide the appropriate voltage levels to each component on the board, or
using a Li-Polymer battery via an onboard battery connector. All communication methods that mikroBUS™ itself supports are on this board, including the well-established mikroBUS™ socket, reset button, and several user-configurable buttons and LED indicators. Clicker 2 for Kinetis is an integral part of the Mikroe ecosystem, allowing you to create a new application in minutes. Natively supported by Mikroe software tools, it covers many aspects of prototyping 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
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
NXP
Pin count
121
RAM (Bytes)
262144
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 Clicker 2 for Kinetis 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 Barometer Click driver.
Key functions:
barometer_get_temperature_c- Read temperature in degrees Celsius functionbarometer_get_pressure- Read pressure in milibars functionbarometer_check_status- Check sensor status function
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 Barometer Click example
*
* # Description
* This application measures temperature and pressure data.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Initialization driver enable's - I2C, set default configuration and start write log.
*
* ## Application Task
* This is a example which demonstrates the use of Barometer Click board.
* ## NOTE
* External pull-up resistors are required on I2C lines, if the Click board is configured for I2C mode.
*
*
* \author MikroE Team
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "barometer.h"
// ------------------------------------------------------------------ VARIABLES
static barometer_t barometer;
static log_t logger;
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
barometer_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.
barometer_cfg_setup( &cfg );
BAROMETER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
barometer_init( &barometer, &cfg );
barometer_default_cfg( &barometer );
// Check sensor id
if ( barometer_check_id( &barometer ) != BAROMETER_DEVICE_ID )
{
log_printf( &logger, " ERROR \r\n " );
}
else
{
log_printf( &logger, " Initialization \r\n" );
}
log_printf( &logger, "-------------------------------- \r\n" );
Delay_100ms( );
}
void application_task ( void )
{
float temperature_c;
float pressure;
temperature_c = barometer_get_temperature_c( &barometer );
Delay_100ms( );
pressure = barometer_get_pressure( &barometer );
Delay_100ms( );
log_printf( &logger, " Temperature : %.2f\r\n", temperature_c );
log_printf( &logger, " Pressure : %.2f\r\n", pressure );
log_printf( &logger, "-------------------------------- \r\n" );
Delay_1sec( );
}
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
