Diff Press 2 Click

Diff Press 2 Click is a compact add-on board that contains Sensirion’s differential pressure sensor. This board features the SDP31-500PA, a small differential pressure sensor designed for high-volume applications. The SDP31-500PA comes with a configurable host interface that supports I2C serial communication and measures pressure in a range from -500Pa up to +500Pa with an accuracy of 3%. It comes as calibrated and temperature compensated with high reliability/long-term stability, has the best signal-to-noise ratio. It operates in a temperature range of -40°C to 85°C, ensuring stable operation under extreme conditions.

Click Product page

Click library

• Author : Luka Filipovic
• Date : Sep 2021.
• Type : I2C type

Software Support

We provide a library for the DiffPress2 Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for DiffPress2 Click driver.

Standard key functions :

• diffpress2_cfg_setup Config Object Initialization function.

  void diffpress2_cfg_setup ( diffpress2_cfg_t *cfg );

• diffpress2_init Initialization function.

  err_t diffpress2_init ( diffpress2_t *ctx, diffpress2_cfg_t *cfg );

• diffpress2_default_cfg Click Default Configuration function.

  err_t diffpress2_default_cfg ( diffpress2_t *ctx );

Example key functions :

• diffpress2_get_id Reads device ID's

  err_t diffpress2_get_id ( diffpress2_t *ctx );

• diffpress2_reset Reset device

  err_t diffpress2_reset ( diffpress2_t *ctx );

• diffpress2_trigger_measurement Pressure and temperature reading

  err_t diffpress2_trigger_measurement ( diffpress2_t *ctx, uint16_t trigger_type, 
                                       float *diff_press, float *temperature );

Example Description

This example application showcases ability for device to read and calculate mass flow or diff press pressure in Pascals and temperature in degrees Celsius.

The demo application is composed of two sections :

Application Init

Initialization of module communication(I2C, UART) and additional interrupt pin. Resets device and reads serial and product ID's and logs them.

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    diffpress2_cfg_t diffpress2_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.
    diffpress2_cfg_setup( &diffpress2_cfg );
    DIFFPRESS2_MAP_MIKROBUS( diffpress2_cfg, MIKROBUS_1 );
    err_t init_flag = diffpress2_init( &diffpress2, &diffpress2_cfg );
    if ( I2C_MASTER_ERROR == init_flag ) 
    {
        log_error( &logger, " Application Init Error. " );
        log_info( &logger, " Please, run program again... " );
        for ( ; ; );
    }

    if ( diffpress2_default_cfg ( &diffpress2 ) ) 
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }

    log_printf( &logger, " > Product ID: 0x%.8LX\r\n", diffpress2.product_id );
    log_printf( &logger, " > Serial ID: 0x%.8LX%.8LX\r\n", 
                diffpress2.serial_id[ 0 ], diffpress2.serial_id[ 1 ] );

    log_info( &logger, " Application Task " );
}

Application Task

Read and calculate differential in Pascal and temperature in degrees Celsius every 300ms.

void application_task ( void )
{
    float pressure;
    float temperature;

    if ( diffpress2_trigger_measurement( &diffpress2, DIFFPRESS2_CMD_TRIGGER_MEAS_DIFF_PRESS, 
                                         &pressure, &temperature ) )
    {
        log_error( &logger, " Read data." );
    }
    else
    {
        log_printf( &logger, " > Pressure[Pa]: %.2f\r\n", pressure );
        log_printf( &logger, " > Temperature[degC]: %.2f\r\n", temperature );
        log_printf( &logger, "*************************************\r\n" );
    }

    Delay_ms ( 300 );
}

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager(recommended way), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.DiffPress2

Additional notes and informations

Depending on the development board you are using, you may need USB UART Click, USB UART 2 Click or RS232 Click to connect to your PC, for development systems with no UART to USB interface available on the board. UART terminal is available in all MikroElektronika compilers.