Intermediate
30 min

Experience the power of touch with CAP1114 and PIC18LF47K42

Say goodbye to clunky buttons and switches

CapSense 2 Click with EasyPIC v8

Published Apr 24, 2023

Click board™

CapSense 2 Click

Dev Board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18LF47K42

Take control of your touch-sensing applications with a slide switch and touch buttons that offers high sensitivity and responsiveness

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Hardware Overview

How does it work?

CapSense 2 Click is based on 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 feature 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 the 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 only be operated 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.

capsense-2-click-hardware-overview

Features overview

Development board

EasyPIC v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports many high pin count 8-bit PIC microcontrollers from Microchip, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer. The development board is well organized and designed so that the end-user has all the necessary elements, such as switches, buttons, indicators, connectors, and others, in one place. Thanks to innovative manufacturing technology, EasyPIC v8 provides a fluid and immersive working experience, allowing access anywhere and under any

circumstances at any time. Each part of the EasyPIC v8 development board contains the components necessary for the most efficient operation of the same board. In addition to the advanced integrated CODEGRIP programmer/debugger module, which offers many valuable programming/debugging options and seamless integration with the Mikroe software environment, the board also includes a clean and regulated power supply module for the development board. It can use a wide range of external power sources, including a battery, an external 12V power supply, and a power source via the USB Type-C (USB-C) connector.

Communication options such as USB-UART, USB DEVICE, and CAN are also included, including the well-established mikroBUS™ standard, two display options (graphical and character-based LCD), and several different DIP sockets. These sockets cover a wide range of 8-bit PIC MCUs, from the smallest PIC MCU devices with only eight up to forty pins. EasyPIC v8 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 v8 horizontal image

Microcontroller Overview

MCU Card / MCU

PIC18LF47K42

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

8192

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
Reset
RE1
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
Interrupt
RB0
INT
NC
NC
TX
NC
NC
RX
I2C Clock
RC3
SCL
I2C Data
RC4
SDA
NC
NC
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

CapSense 2 Click Schematic schematic

Step by step

Project assembly

EasyPIC v8 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyPIC v8 as your development board.

EasyPIC v8 front image hardware assembly
Buck 22 Click front image hardware assembly
MCU DIP 40 hardware assembly
EasyPIC v8 DIP MB 1 - 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
Necto image step 8 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

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

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.

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * @file main.c
 * @brief CapSense2 Click example
 *
 * # Description
 * This example demonstrates the use of CapSense 2 click board by reading 
 * and displaying the sensor's events.
 *
 * The demo application is composed of two sections :
 *
 * ## Application Init
 * Initializes the driver and performs the click default configuration
 * which resets the click board and links the desired LEDs to buttons and swipe sensors.
 *
 * ## Application Task
 * Waits for an event interrupt and displays the event on the USB UART.
 *
 * @author Stefan Filipovic
 *
 */

#include "board.h"
#include "log.h"
#include "capsense2.h"

static capsense2_t capsense2;
static log_t logger;

void application_init ( void ) 
{
    log_cfg_t log_cfg;  /**< Logger config object. */
    capsense2_cfg_t capsense2_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.
    capsense2_cfg_setup( &capsense2_cfg );
    CAPSENSE2_MAP_MIKROBUS( capsense2_cfg, MIKROBUS_1 );
    if ( I2C_MASTER_ERROR == capsense2_init( &capsense2, &capsense2_cfg ) ) 
    {
        log_error( &logger, " Communication init." );
        for ( ; ; );
    }
    
    if ( CAPSENSE2_ERROR == capsense2_default_cfg ( &capsense2 ) )
    {
        log_error( &logger, " Default configuration." );
        for ( ; ; );
    }
    
    log_info( &logger, " Application Task " );
}

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 \r\n\n" );
                    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 \r\n\n" );
                    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 \r\n\n" );
                    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 \r\n\n" );
                    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 \r\n\n" );
                    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 \r\n\n" );
                    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 \r\n\n", ( uint16_t ) slider );
                }
                else
                {
                    swipe_state = 0;
                }
            }
        }
        capsense2_clear_interrupt ( &capsense2 );
    }
}

void main ( void ) 
{
    application_init( );

    for ( ; ; ) 
    {
        application_task( );
    }
}

// ------------------------------------------------------------------------ END

Additional Support

Resources

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