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Reach new heights with MPL3115A2 and PIC18LF26K22

Measure height relative to sea level or ground level

Altitude Click with EasyPIC v7

Published Nov 01, 2023

Click board™

Altitude Click

Development board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18LF26K22

Provide accurate measurements of the current altitude or elevation of an object or location with high resolution and reliability

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Hardware Overview

How does it work?

Altitude Click is based on the MPL3115A2, a low-power, high-accuracy digital output altimeter, barometer, and thermometer from NXP Semiconductors. A high-resolution 24-bit ADC digitizes the MPL3115A2 outputs; it provides 20-bit pressure/altitude and 12-bit temperature data with an altitude resolution of 30cm. Pressure output can be resolved with output in fractions of a Pascal and altitude in fractions of a meter. The high stability of both pressure and temperature signals makes it suitable for accurate altimetry in various applications. The MPL3115A2 contains automatic internal data processing with data acquisition and compensation, which removes compensation tasks from the host MCU, and a 32-sample FIFO buffer to minimize the overhead of collecting multiple data

samples. Numerous user-programmable, power-saving, and interrupt modes are available, including programmed acquisition cycle timing and poll-only modes. It can also autonomously collect data at programmed intervals and store it for up to 12 days, depending on the data acquisition rate (1 second - 9 hours). This Click board™ communicates with MCU using the standard I2C 2-Wire interface with a maximum clock frequency of 400kHz. The MPL3115A2 also features two independently programmable interrupt signals, IT1 and IT2, routed to the INT and CS pins on the mikroBUS™ socket, entirely programmed by the user through the I2C interface (functions, threshold, and the timing of the interrupt pins). These can be set to generate an interrupt signal when a new set

of pressure/altitude and temperature data is available, simplifying data acquisition for the host MCU. It can also be configured to generate interrupts when a user-programmed set of conditions are met, such as when a single new data acquisition is ready, when a desired number of samples are stored within the internal FIFO, or when a change of pressure/altitude or temperature is detected. 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.

Altitude Click hardware overview image

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.

EasyPIC v7 horizontal image

Microcontroller Overview

MCU Card / MCU

default

Architecture

PIC

MCU Memory (KB)

64

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3896

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
Interrupt 2
RA5
CS
NC
NC
SCK
NC
NC
MISO
NC
NC
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
Interrupt 1
RB1
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
2

Take a closer look

Schematic

Altitude Click Schematic 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.

EasyPIC v7 front image hardware assembly
Rotary B 2 Click front image hardware assembly
MCU DIP 28 hardware assembly
EasyPIC v7 MB 2 - 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
EasyPIC PRO v7a Display Selection Necto Step 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 Altitude Click driver.

Key functions:

  • altitude_generic_single_write - Generic Single Write function

  • altitude_generic_multiple_read - Generic Multiple Read function

  • altitude_get_altitude - Altitude Get function

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 Altitude Click example
 *
 * # Description
 * This is a example which demonstrates the use of Altitude Click board.
 * This demo example offers the altitude [m], pressure [mbar] and temperature
 * [deg C] measurements from sensor.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes I2C driver and all used pins, performs a default configuration
 * for Altitude Click board and initializes the uart console for results
 * logging.
 *
 * ## Application Task
 * Shows two different uses of sensor, altimeter and barometer mode.
 * Reads the altitude, pressure and temperature results in standard units and
 * sends this results to the console.
 *
 * \author Nemanja Medakovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "altitude.h"


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

static altitude_t altitude;
static log_t console;

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

void application_init( void )
{
    altitude_cfg_t altitude_cfg;
    log_cfg_t log_cfg;

    //  Click initialization.
    altitude_cfg_setup( &altitude_cfg );
    ALTITUDE_MAP_MIKROBUS( altitude_cfg, MIKROBUS_1 );
    altitude_init( &altitude, &altitude_cfg );
    altitude_default_cfg( &altitude );

    /** 
     * 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( &console, &log_cfg );
    log_printf( &console, "***  Altitude initialization done  ***\r\n" );
    log_printf( &console, "**************************************\r\n" );
}

void application_task( void )
{
    float altitude_result;
    float pressure_result;
    float temperature_result;

    //  Altimeter sensor mode for altitude data reading.
    altitude_set_sensor_mode( &altitude, ALTITUDE_SENSMOD_ALTIMETER );
    Delay_ms( 100 );

    while ( 0 == altitude_get_drdy_status( &altitude, ALTITUDE_STATUS_FLAG_PDR ) );

    altitude_result = altitude_get_altitude( &altitude );

    //  Barometer sensor mode for pressure data reading.
    altitude_set_sensor_mode( &altitude, ALTITUDE_SENSMOD_BAROMETER );
    Delay_ms( 100 );

    while ( 0 == altitude_get_drdy_status( &altitude, ALTITUDE_STATUS_FLAG_PDR ) );

    pressure_result = altitude_get_pressure( &altitude );
    temperature_result = altitude_get_temperature( &altitude );

    log_printf( &console, "** Altitude is %.2f m\r\n", altitude_result );
    log_printf( &console, "** Pressure is %.2f mbar\r\n", pressure_result );
    log_printf( &console, "** Temperature is %.2f Celsius\r\n", temperature_result );
    log_printf( &console, "**************************************\r\n" );
}

void main( void )
{
    application_init( );
    
    for ( ; ; )
    {
        application_task( );
    }
}

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

Additional Support

Resources