Intermediate
30 min

Monitor and control pressure differentials with ease using LMIS025B and PIC18LF2682

Digital excellence in pressure sensing

VAV Press Click with EasyPIC v7

Published Dec 29, 2023

Click board™

VAV Press Click

Dev Board

EasyPIC v7

Compiler

NECTO Studio

MCU

PIC18LF2682

Our digital differential pressure sensor is engineered to provide precise and reliable readings for a wide range of applications, from industrial automation to environmental monitoring

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Hardware Overview

How does it work?

VAV Press Click is based on the LMIS025B, a low differential pressure sensor from TE Connectivity that offers a digital output for reading pressure over the specified pressure span. The innovative LMI technology features superior sensitivity, especially for ultra-low pressures ranging from 0 to 25Pa / 0 to 0.25mbar (0.1 in H2O). It is based on thermal flow measurement of gas through a micro-flow channel integrated within the sensor chip. The extremely low gas flow through the sensor ensures high immunity to dust contamination, humidity, and long tubing compared to other flow-based pressure sensors,

including the outstanding long-term stability, precision with patented real-time offset compensation, and linearization techniques. The LMIS025B offers two modes of operation: Continuous mode with a 5ms sampling time, which provides a near-continuous stream of pressure data, and low-power mode with a 400μA Standby current which wakes the device from Sleep to serve pressure data “on-demand”. The first measurement in either mode is available after a warm-up and conversion sequence, which takes approximately 25 ms. VAV Press Click communicates with MCU using the standard I2C

2-Wire interface, offering linearized digital output through a 16-bit sigma-delta A/D conversion. Besides, it also allows the choice of the least significant bit of its I2C slave address by positioning the SMD jumper labeled as ADDR SEL to an appropriate position marked as 0 and 1. 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. Also, it comes equipped with a library containing functions and an example code that can be used as a reference for further development.

VAV Press Click top side image
VAV Press Click bottom side 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)

80

Silicon Vendor

Microchip

Pin count

28

RAM (Bytes)

3328

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
NC
NC
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

VAV Press 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
LTE IoT 5 Click front image hardware assembly
MCU DIP 28 hardware assembly
LTE IoT 5 Click complete accessories setup image hardware assembly
EasyPIC v7 Access 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 via UART Mode

1. Once the code example is loaded, pressing the "FLASH" button initiates the build process, and programs it on the created setup.

2. After the programming is completed, click on the Tools icon in the upper-right panel, and select the UART Terminal.

3. After opening the UART Terminal tab, first check the baud rate setting in the Options menu (default is 115200). If this parameter is correct, activate the terminal by clicking the "CONNECT" button.

4. Now terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.

UART_Application_Output

Software Support

Library Description

This library contains API for VAV Press Click driver.

Key functions:

  • vavpress_set_default_sensor_param - VAV Press set default sensor parameter function

  • vavpress_get_dif_press_and_temp - VAV Press get differential pressure and temperature function

  • vavpress_retrieve_electronic_signature - VAV Press retrieve electronic signature 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 VavPress Click example
 *
 * # Description
 * This library contains API for the Vav Press click driver.
 * This demo application shows an example of 
 * differential pressure and temperature measurement.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of I2C module and log UART.
 * After driver initialization and default settings, 
 * the app display retrieve the electronic signature 
 * and set the sensor parameters data.
 *
 * ## Application Task
 * This is an example that shows the use of a Vav Press click board™.
 * Logs pressure difference value [ Pa ] and temperature [ degree Celsius ] value.
 * Results are being sent to the Usart Terminal where you can track their changes.
 * 
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "vavpress.h"

static vavpress_t vavpress;
static log_t logger;
static float diff_press;
static float temperature;
vavpress_el_signature_data_t el_signature_data;
vavpress_sensor_param_data_t param_data;

void application_init ( void ) {
    log_cfg_t log_cfg;            /**< Logger config object. */
    vavpress_cfg_t vavpress_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_printf( &logger, "\r\n" );
    log_info( &logger, " Application Init " );

    // Click initialization.

    vavpress_cfg_setup( &vavpress_cfg );
    VAVPRESS_MAP_MIKROBUS( vavpress_cfg, MIKROBUS_1 );
    err_t init_flag = vavpress_init( &vavpress, &vavpress_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    vavpress_default_cfg ( &vavpress );
    log_info( &logger, " Application Task " );
    Delay_ms ( 100 );
    
    vavpress_retrieve_electronic_signature( &vavpress, &el_signature_data );
    Delay_ms ( 100 );

    log_printf( &logger, "--------------------------------\r\n" );
    log_printf( &logger, " Firmware Version : %.3f        \r\n", el_signature_data.firmware_version );
    log_printf( &logger, " Pressure Range   : %d Pa       \r\n", el_signature_data.pressure_range );
    log_printf( &logger, " Part #           : %.11s       \r\n", el_signature_data.part_number );
    log_printf( &logger, " Lot #            : %.7s        \r\n", el_signature_data.lot_number );
    log_printf( &logger, " Output Type      : %c          \r\n", el_signature_data.output_type );
    log_printf( &logger, " Scale Factor     : %d          \r\n", el_signature_data.scale_factor );
    log_printf( &logger, " Calibration ID   : %.2s        \r\n", el_signature_data.calibration_id );
    log_printf( &logger, " Week number      : %d          \r\n", el_signature_data.week_number );
    log_printf( &logger, " Year number      : %d          \r\n", el_signature_data.year_number );
    log_printf( &logger, " Sequence number  : %d          \r\n", el_signature_data.sequence_number );
    log_printf( &logger, "--------------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    param_data.scale_factor_temp = 72;
    param_data.scale_factor_press = el_signature_data.scale_factor;
    param_data.readout_at_known_temperature = 50;
    param_data.known_temperature_c = 24.0;
    Delay_ms ( 100 );
}

void application_task ( void ) {   
    err_t error_flag = vavpress_get_dif_press_and_temp( &vavpress, &param_data, &diff_press, &temperature );
    if ( error_flag == VAVPRESS_OK ) {
        log_printf( &logger, " Diff. Pressure    : %.4f Pa\r\n", diff_press );
        log_printf( &logger, " Temperature       : %.4f C\r\n", temperature );
        log_printf( &logger, "--------------------------------\r\n" );
        Delay_ms ( 1000 ); 
        Delay_ms ( 1000 );
    } else {
        log_error( &logger, " Communcation Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
}

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
/*!
 * @file main.c
 * @brief VavPress Click example
 *
 * # Description
 * This library contains API for the Vav Press click driver.
 * This demo application shows an example of 
 * differential pressure and temperature measurement.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initialization of I2C module and log UART.
 * After driver initialization and default settings, 
 * the app display retrieve the electronic signature 
 * and set the sensor parameters data.
 *
 * ## Application Task
 * This is an example that shows the use of a Vav Press click board™.
 * Logs pressure difference value [ Pa ] and temperature [ degree Celsius ] value.
 * Results are being sent to the Usart Terminal where you can track their changes.
 * 
 *
 * @author Nenad Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "vavpress.h"

static vavpress_t vavpress;
static log_t logger;
static float diff_press;
static float temperature;
vavpress_el_signature_data_t el_signature_data;
vavpress_sensor_param_data_t param_data;

void application_init ( void ) {
    log_cfg_t log_cfg;            /**< Logger config object. */
    vavpress_cfg_t vavpress_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_printf( &logger, "\r\n" );
    log_info( &logger, " Application Init " );

    // Click initialization.

    vavpress_cfg_setup( &vavpress_cfg );
    VAVPRESS_MAP_MIKROBUS( vavpress_cfg, MIKROBUS_1 );
    err_t init_flag = vavpress_init( &vavpress, &vavpress_cfg );
    if ( init_flag == I2C_MASTER_ERROR ) {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }

    vavpress_default_cfg ( &vavpress );
    log_info( &logger, " Application Task " );
    Delay_ms ( 100 );
    
    vavpress_retrieve_electronic_signature( &vavpress, &el_signature_data );
    Delay_ms ( 100 );

    log_printf( &logger, "--------------------------------\r\n" );
    log_printf( &logger, " Firmware Version : %.3f        \r\n", el_signature_data.firmware_version );
    log_printf( &logger, " Pressure Range   : %d Pa       \r\n", el_signature_data.pressure_range );
    log_printf( &logger, " Part #           : %.11s       \r\n", el_signature_data.part_number );
    log_printf( &logger, " Lot #            : %.7s        \r\n", el_signature_data.lot_number );
    log_printf( &logger, " Output Type      : %c          \r\n", el_signature_data.output_type );
    log_printf( &logger, " Scale Factor     : %d          \r\n", el_signature_data.scale_factor );
    log_printf( &logger, " Calibration ID   : %.2s        \r\n", el_signature_data.calibration_id );
    log_printf( &logger, " Week number      : %d          \r\n", el_signature_data.week_number );
    log_printf( &logger, " Year number      : %d          \r\n", el_signature_data.year_number );
    log_printf( &logger, " Sequence number  : %d          \r\n", el_signature_data.sequence_number );
    log_printf( &logger, "--------------------------------\r\n" );
    Delay_ms ( 1000 );
    Delay_ms ( 1000 );
    
    param_data.scale_factor_temp = 72;
    param_data.scale_factor_press = el_signature_data.scale_factor;
    param_data.readout_at_known_temperature = 50;
    param_data.known_temperature_c = 24.0;
    Delay_ms ( 100 );
}

void application_task ( void ) {   
    err_t error_flag = vavpress_get_dif_press_and_temp( &vavpress, &param_data, &diff_press, &temperature );
    if ( error_flag == VAVPRESS_OK ) {
        log_printf( &logger, " Diff. Pressure    : %.4f Pa\r\n", diff_press );
        log_printf( &logger, " Temperature       : %.4f C\r\n", temperature );
        log_printf( &logger, "--------------------------------\r\n" );
        Delay_ms ( 1000 ); 
        Delay_ms ( 1000 );
    } else {
        log_error( &logger, " Communcation Error. " );
        log_info( &logger, " Please, run program again... " );

        for ( ; ; );
    }
}

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

Additional Support

Resources

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