Pressure 13 Click

How does it work?

Pressure 13 Click is based on the KP229E2701, a miniaturized analog absolute pressure sensor based on a capacitive principle from Infineon. The pressure is detected by an array of capacitive surface micromachined sensor cells (a monolithic integrated signal conditioning circuit implemented in BiCMOS technology). The sensor cell output is amplified, temperature compensated, and linearized to obtain an output voltage that is proportional to the applied pressure. The manifold air pressure (MAP) is a principal parameter to compute the air-fuel ratio provided to the engine for lower emission due to better combustion and increased efficiency. For cost-sensitive engine systems, a MAP sensor shows the potential to complement or even substitute mass airflow (MAF) sensors.

The accuracy of the KP229E2701 sensor is influenced by the supply voltage (ratiometric error) as well as by pressure, temperature, and aging effects. All parameters needed for the complete calibration algorithm – such as offset, gain, temperature coefficients of offset and gain, and linearization parameters – are determined after the assembly. These parameters are stored in an integrated E²PROM protected with forwarding error correction (a one-bit error is detected and corrected, errors of more than one bit are detected, and the output signal is switched to ground potential).

In automotive applications where high production volumes are custom, there is substantial interest in precision, low-cost, and fully integrated sensors. That’s why the manifold pressure data can be used to compute diagnostics of leakages and malfunctions of the exhaust gas recirculation valve.

Pressure 13 Click communicates with MCU using only one GPIO pin routed on the AN pin of the mikroBUS™ socket. The KP229E2701 sensor possesses several digital pins used only during calibration and test. That’s why it’s recommended and done to leave these pins floating. The output circuit acts as a low-pass decoupling filter between the sensor output and the A/D input of the MCU because it’s recommended to protect the pressure sensor against overload and electromagnetic interferences.

This Click board™ is designed to be operated only with a 5V logic voltage level. A proper logic voltage level conversion should be performed before the Click board™ is used with MCUs with different logic levels. However, the Click board™ comes equipped with a library that contains easy to use functions and an example code that can be used as a reference for further development.

Specifications

Pinout diagram

This table shows how the pinout on Pressure 13 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Analog Pressure Signal Output	AN	1	AN	PWM	16	NC
	NC	2	RST	INT	15	NC
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
	NC	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Pressure 13 Click electrical specifications

Software Support

We provide a library for the Pressure 13 Click on our LibStock page, as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Library Description

The library covers all the necessary functions to control Pressure 13 click board.

Key functions:

• void pressure13_gpio_driver_init( pressure13_obj_t gpio_obj ) – Function initializes GPIO driver for the desired MIKROBUS1.

Examples description

The application is composed of three sections :

• System Initialization – Initializes GPIO and start to write log.
• Application Initialization – Initialization driver enables – GPIO, initializes ADC, also write log.
• Application Task – (code snippet) This is an example which demonstrates the use of Pressure 13 Click board. Measured and display ADC, Vout ( V ) and pressure data ( mBar ). Results are being sent to the Usart Terminal where you can track their changes. All data logs on usb uart for aproximetly every 5 sec.

  void application_task ( )
  {
      adc_value = pressure13_adc_read( );
      
      WordToStr( adc_value, log_text );
      Ltrim( log_text );
      mikrobus_logWrite( " ADC     : ", _LOG_TEXT );
      mikrobus_logWrite( log_text, _LOG_LINE );
  
      calculate_pressure( );
      
      FloatToStr( v_out, log_text );
      mikrobus_logWrite( " Vout    : ", _LOG_TEXT );
      mikrobus_logWrite( log_text, _LOG_TEXT );
      mikrobus_logWrite( " V", _LOG_LINE );
      
      FloatToStr( pressure, log_text );
      mikrobus_logWrite( " Pressure: ", _LOG_TEXT );
      mikrobus_logWrite( log_text, _LOG_TEXT );
      mikrobus_logWrite( " mBar", _LOG_LINE );
      mikrobus_logWrite( "-------------------------", _LOG_LINE );
      Delay_ms( 5000 );
  }
  

• void calculate_pressure ( void ) – Calculate Voltage Reference and Pressure.

The full application code, and ready to use projects can be found on our LibStock page.

Other mikroE Libraries used in the example:

• ADC
• UART
• Conversions

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. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

mikroSDK

This Click board™ is supported with mikroSDK – MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant Click board™ demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.

For more information about mikroSDK, visit the official page.