CapSense 2 Click

How does it work?

CapSense 2 Click as its foundation uses the CAP1114, a multi-channel capacitive touch sensor from Microchip. The CAP1114 takes human body capacitance as an input and directly provides real-time sensor information via a serial interface. It also comes with programmable sensitivity for touch buttons and slider switch applications.

The CAP1114 contains multiple power states, including several low-power operating states. It has four operational states: Fully Active, Sleep, Deep Sleep, and Inactive depending on the status of the SLEEP, DEACT, and DSLEEP register bits. When the device transitions between power states, previously detected touches (for deactivated channels) are cleared, and the status bits reset.

As mentioned earlier, this board contains a 7-segment capacitive sensing slider that can detect a slide in either the UP or DOWN direction, as well as two touch buttons. These pads are the only elements on the top side of the board, allowing the protective acrylic plexiglass layer placement. Each of these features has an LED indicator representing the activity in that field. If a touch event is detected on one of these onboard pads, the state of the corresponding LED will be changed, indicating an activated channel; more precisely, touch has been detected on that specific field.

CapSense 2 Click communicates with MCU using the standard I2C 2-Wire interface to read data and configure settings. It also possesses an additional alert interrupt signal, routed on the INT pin of the mikroBUS™ socket labeled as ALT, indicating when a specific interrupt event occurs (touch detection), and Reset pin routed to the RST pin of the mikroBUS™ socket used to hold all internal blocks of the CAP1114 in a reset state.

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.

Specifications

Pinout diagram

This table shows how the pinout on CapSense 2 Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
	NC	1	AN	PWM	16	NC
Reset	RST	2	RST	INT	15	ALT	Interrupt
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	SCL	I2C Clock
	NC	6	MOSI	SDA	11	SDA	I2C Data
Power Supply	3.3V	7	3.3V	5V	10	NC
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

CapSense 2 Click electrical specifications

Software Support

We provide a library for the CapSense 2 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 CapSense 2 Click driver.

Key functions

• capsense2_read_register This function reads a data byte from the selected register by using I2C serial interface.

• capsense2_get_alert_pin This function returns the alert pin logic state.

• capsense2_clear_interrupt This function clears the INT bit of the main status register if the interrupt pin is asserted.

Example Description

This example demonstrates the use of CapSense 2 Click board™ by reading and displaying the sensor's events.

void application_task ( void ) 
 { 
     if ( capsense2_get_alert_pin ( &capsense2 ) ) 
     { 
         uint8_t button_status = 0; 
         if ( CAPSENSE2_OK == capsense2_read_register ( &capsense2, CAPSENSE2_REG_BUTTON_STATUS_1, &button_status ) ) 
         { 
             static uint8_t button_press_state = 0; 
             static uint8_t swipe_state = 0; 
             if ( button_status & CAPSENSE2_BUTTON_STATUS_1_UP_SLIDER ) 
             { 
                 if ( CAPSENSE2_BUTTON_STATUS_1_UP_SLIDER != swipe_state ) 
                 { 
                     log_printf ( &logger, " Swipe UP rnn" ); 
                     swipe_state = CAPSENSE2_BUTTON_STATUS_1_UP_SLIDER; 
                 } 
             } 
             if ( button_status & CAPSENSE2_BUTTON_STATUS_1_DOWN_SLIDER ) 
             { 
                 if ( CAPSENSE2_BUTTON_STATUS_1_DOWN_SLIDER != swipe_state ) 
                 { 
                     log_printf ( &logger, " Swipe DOWN rnn" ); 
                     swipe_state = CAPSENSE2_BUTTON_STATUS_1_DOWN_SLIDER; 
                 } 
             } 
             if ( button_status & CAPSENSE2_BUTTON_STATUS_1_BUTTON_1 ) 
             { 
                 if ( !( button_press_state & CAPSENSE2_BUTTON_STATUS_1_BUTTON_1 ) ) 
                 { 
                     log_printf ( &logger, " Button 1 pressed rnn" ); 
                     button_press_state |= CAPSENSE2_BUTTON_STATUS_1_BUTTON_1; 
                 } 
             } 
             if ( button_status & CAPSENSE2_BUTTON_STATUS_1_BUTTON_2 ) 
             { 
                 if ( !( button_press_state & CAPSENSE2_BUTTON_STATUS_1_BUTTON_2 ) ) 
                 { 
                     log_printf ( &logger, " Button 2 pressed rnn" ); 
                     button_press_state |= CAPSENSE2_BUTTON_STATUS_1_BUTTON_2; 
                 } 
             } 
             capsense2_clear_interrupt ( &capsense2 ); 

             // check if buttons are released 
             if ( CAPSENSE2_OK == capsense2_read_register ( &capsense2, CAPSENSE2_REG_BUTTON_STATUS_1, &button_status ) ) 
             { 
                 if ( ( button_press_state & CAPSENSE2_BUTTON_STATUS_1_BUTTON_1 ) &&  
                     !( button_status & CAPSENSE2_BUTTON_STATUS_1_BUTTON_1 ) ) 
                 { 
                     log_printf ( &logger, " Button 1 released rnn" ); 
                     button_press_state &= ~CAPSENSE2_BUTTON_STATUS_1_BUTTON_1; 
                 } 
                 if ( ( button_press_state & CAPSENSE2_BUTTON_STATUS_1_BUTTON_2 ) &&  
                     !( button_status & CAPSENSE2_BUTTON_STATUS_1_BUTTON_2 ) ) 
                 { 
                     log_printf ( &logger, " Button 2 released rnn" ); 
                     button_press_state &= ~CAPSENSE2_BUTTON_STATUS_1_BUTTON_2; 
                 } 
             } 

             // check if swipe event is finished and display the slider position 
             uint8_t slider = 0; 
             if ( CAPSENSE2_OK == capsense2_read_register ( &capsense2, CAPSENSE2_REG_SLIDER_POSITION_DATA, &slider ) ) 
             { 
                 if ( slider ) 
                 { 
                     log_printf ( &logger, " Slider position: %u rnn", ( uint16_t ) slider ); 
                 } 
                 else 
                 { 
                     swipe_state = 0; 
                 } 
             } 
         } 
         capsense2_clear_interrupt ( &capsense2 ); 
     } 
 }

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.CapSense2

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.

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.