Create a futuristic and user-friendly interface using IQS333 and PIC18F27K40

Elegance in control

Published Nov 01, 2023

Click board™

Cap Wheel Click

Dev. board

EasyPIC v8

Compiler

NECTO Studio

MCU

PIC18F27K40

Elevate your experience with our capacitive touch button that delivers precision and responsiveness, making every interaction a delightful journey

Hardware Overview

How does it work?

CAP Wheel Click is based on the IQS333, ProxSense® IC, a 9-channel projected (or 7-channel self) capacitive proximity, and a touch controller from Azoteq. This IC has advanced features such as auto drift compensation, Long proximity range, Automatic adjustment for optimal performance (ATI), two Configurable 11-bit sliders/scroll wheels, and more. These features enable CAP Wheel Click to exhibit reliable and accurate touch detection. Capacitive touch sensing is based on detecting a change in capacitance due to the influence of a foreign object. The capacitance of the sensor, also known as the antenna, is measured and monitored, and if a significant change occurs after processing by the detection integrator, a touch event is

acknowledged. Many routing requirements need to be met in the sensing electrode design to maximize performance. The relation between the sensing elements in position and size is crucial. CAP Wheel click is designed with these requirements, and electrodes are „Self-Capacitive Wheel“ shaped. CAP Wheel click also contains 8 LEDs whose function can be user-defined. LEDs are connected to PWM LED driver pins on IQS333, so the user can turn LEDs on or off and control illumination using the dimming modes that IQS333 supports. The IQS333 IC interfaces to a master controller via a 3-wire (SDA, SCL, and RDY) serial interface bus that is I2C™ compatible, with a maximum communication speed of 400kbit/s. The host MCU can force communication anytime by

pulling the RDY line low. The communication will start directly following the current conversion cycle. If the watchdog timer terminates the event, the device will reset. After every power-on cycle, the device will recalibrate itself. It will take some time, so it should be considered when building custom applications. MikroElektronika provides libraries and the demo application to be used as a reference for future designs. As mentioned, this Click board™ is I2C compatible and uses SCL, SDA, and RDY pins for communication routed to SCL, SDA, and INT pins on mikroBUS™, respectively. Besides that, a CLR pin is available on board which is routed to the RST pin on mikroBUS™ and used to master reset the IC.

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.

Microcontroller Overview

MCU Card / MCU

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

3728

Used MCU Pins

mikroBUS™ mapper

Master Clear

RA0

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

Data Ready

RB1

INT

I2c Clock

RC3

SCL

I2C Data

RC4

SDA

Ground

GND

Take a closer look

Click board™ 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.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

Rotary B 2 Click front image hardware assembly

EasyPIC v8 28pin-DIP - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 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 CAP Wheel Click driver.

Key functions:

capwheel_write_reg - Generic Write function
capwheel_read_reg - Generic Read function
capwheel_check_data_ready - Data Ready Check function.

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 
 * \brief CapWheel Click example
 * 
 * # Description
 * This application is use for controling various devices.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initializes I2C interface, performs the device reset and
 * activates the desired channels (from CH0 to CH9), in this example all channels are activated.
 * 
 * ## Application Task  
 * Checks is sense data ready for reading and if was ready, 
  then reads wheel coordinates and sends these results to the LEDs.
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "capwheel.h"

// ------------------------------------------------------------------ VARIABLES

static capwheel_t capwheel;
static log_t logger;

void application_init ( void )
{
    log_cfg_t log_cfg;
    capwheel_cfg_t cfg;

    /** 
     * 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.

    capwheel_cfg_setup( &cfg );
    CAPWHEEL_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    capwheel_init( &capwheel, &cfg );

    capwheel_reset ( &capwheel );
    capwheel_enable_chann( &capwheel, CAPWHEEL_CH0_PROX_EN | CAPWHEEL_CH1_EN | CAPWHEEL_CH2_EN | 
                            CAPWHEEL_CH3_EN | CAPWHEEL_CH4_EN | CAPWHEEL_CH5_EN | CAPWHEEL_CH6_EN | 
                            CAPWHEEL_CH7_EN | CAPWHEEL_CH8_EN | CAPWHEEL_CH9_EN );
    capwheel_set_threshold( &capwheel, 0x03 );
    Delay_ms( 500 );
    
    log_printf( &logger, "CAP Wheel is initialized and ready\r\n" );
}

void application_task ( void )
{
    uint16_t sense_data;
    uint8_t ready_check;

    ready_check = capwheel_check_data_ready( &capwheel );

    if (ready_check == CAPWHEEL_DATA_READY)
    {
        capwheel_get_data( &capwheel, &sense_data );
        
        capwheel_set_output( &capwheel, sense_data, CAPWHEEL_LED_BRIGHTNESS_NUMBER );
    }
}

void main ( void )
{
    application_init( );

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


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