Cap Touch 4 Click

Cap Touch 4 Click is a compact add-on board for wake-on-touch and activation applications. This board features the IQS211B, a single-channel capacitive controller from Azoteq, featuring ProxSense® technology for highly sensitive self-capacitance measurements. The board includes a defined circular touch-sensing area, signal conditioning for parasitic capacitance, and a low-power Sleep mode with wake-up functionality, ensuring efficient energy consumption. It communicates via the I2C interface with a fixed address of 0x47, operates at 3.3V logic, and features the new Click Snap for added flexibility.

Click Product page

Click library

• Author : Stefan Filipovic
• Date : Apr 2024.
• Type : I2C type

Software Support

We provide a library for the Cap Touch 4 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 Cap Touch 4 Click driver.

Standard key functions :

• captouch4_cfg_setup Config Object Initialization function.

  void captouch4_cfg_setup ( captouch4_cfg_t *cfg );

• captouch4_init Initialization function.

  err_t captouch4_init ( captouch4_t *ctx, captouch4_cfg_t *cfg );

• captouch4_default_cfg Click Default Configuration function.

  err_t captouch4_default_cfg ( captouch4_t *ctx );

Example key functions :

• captouch4_read_system_flags This function reads the system flags register.

  err_t captouch4_read_system_flags ( captouch4_t *ctx, uint8_t *sysflags );

• captouch4_read_cap_counts This function reads the counts number directly proportional to capacitance. The system is calibrated to make the counts as sensitive as possible to changes in capacitance for relative measurements.

  err_t captouch4_read_cap_counts ( captouch4_t *ctx, uint16_t *cap_counts );

• captouch4_read_lta This function reads the long-term averate (LTA) value. The LTA is used as reference to compare with capacitance counts.

  err_t captouch4_read_lta ( captouch4_t *ctx, uint16_t *lta );

Example Description

This example demonstrates the use of Cap Touch 4 Click board by reading the proximity, touch, and movement events.

The demo application is composed of two sections :

Application Init

Initializes the driver and performs the Click default configuration.

void application_init ( void )
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    captouch4_cfg_t captouch4_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.
    captouch4_cfg_setup( &captouch4_cfg );
    CAPTOUCH4_MAP_MIKROBUS( captouch4_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == captouch4_init( &captouch4, &captouch4_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }

    if ( CAPTOUCH4_ERROR == captouch4_default_cfg ( &captouch4 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }

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

Application Task

Reads the proximity, touch, and movement events and approximately displays the results on the USB UART every 200ms. The capacitance counts and the long-term average values are also displayed.

void application_task ( void )
{
    uint8_t sys_flags = 0;
    uint8_t movement = 0;
    uint16_t cap_counts = 0;
    uint16_t lta = 0;
    if ( CAPTOUCH4_OK == captouch4_read_system_flags ( &captouch4, &sys_flags ) )
    {
        if ( sys_flags & CAPTOUCH4_SYSFLAGS0_PROX )
        {
            log_printf( &logger, " Proximity detected\r\n" );
        }
        if ( sys_flags & CAPTOUCH4_SYSFLAGS0_TOUCH )
        {
            log_printf( &logger, " Touch detected\r\n" );
        }
        if ( sys_flags & CAPTOUCH4_SYSFLAGS0_MOVEMENT )
        {
            if ( CAPTOUCH4_OK == captouch4_read_movement ( &captouch4, &movement ) )
            {
                log_printf( &logger, " Movement detected: %u\r\n", ( uint16_t ) movement );
            }
        }
        if ( ( sys_flags & CAPTOUCH4_SYSFLAGS0_MOVEMENT ) || 
             ( sys_flags & CAPTOUCH4_SYSFLAGS0_PROX ) || 
             ( sys_flags & CAPTOUCH4_SYSFLAGS0_TOUCH ) )
        {
            if ( CAPTOUCH4_OK == captouch4_read_cap_counts ( &captouch4, &cap_counts ) )
            {
                log_printf( &logger, " Capacitance counts: %u\r\n", cap_counts );
            }
            if ( CAPTOUCH4_OK == captouch4_read_lta ( &captouch4, &lta ) )
            {
                log_printf( &logger, " Long-term average: %u\r\n\n", lta );
            }
        }
        else
        {
            log_printf( &logger, " No detected events\r\n\n" );
        }
    }
    Delay_ms ( 200 );
}

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.CapTouch4

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.