Beginner
10 min

Streamline the operation of complex systems with MC74HC165A and PIC18F47Q10

Streamline your control: 16 buttons, 1 masterpiece

4x4 Key Click with Curiosity HPC

Published Oct 17, 2023

Click board™

4x4 Key Click

Dev. board

Curiosity HPC

Compiler

NECTO Studio

MCU

PIC18F47Q10

Maximize space and functionality by choosing our 16-in-1 button integration solution for your control needs

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Hardware Overview

How does it work?

4x4 Key Click is based on 16 buttons with debounce circuits and two MC74HC165A, 8-bit parallel-in/serial-out shift registers from ON Semiconductor. The rightmost column of the keyboard is marked with letters from A to D, while the other 12 buttons are marked like a telephone keypad, so it is easy to implement this 4x4 Click board to any design. The 16-button output lines go straight to the parallel data inputs of the two shift registers connected in a serial (daisy) chain, thus

occupying fewer pins on the host MCU. The shift registers allow you to press all 16 buttons simultaneously, and each will be registered. The 4X4 Click board uses an SPI serial interface to communicate with the host MCU over the mikroBUS™ socket. In this case, the SPI interface saves as many IO pins of the MCU as possible from 16 buttons using shift registers. The Clock Enable pins of the shift registers are not user-configurable and are tied LOW; thus, shift registers are always

enabled. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the PWR SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

4x4 Key Click hardware overview image

Features overview

Development board

Curiosity HPC, standing for Curiosity High Pin Count (HPC) development board, supports 28- and 40-pin 8-bit PIC MCUs specially designed by Microchip for the needs of rapid development of embedded applications. This board has two unique PDIP sockets, surrounded by dual-row expansion headers, allowing connectivity to all pins on the populated PIC MCUs. It also contains a powerful onboard PICkit™ (PKOB), eliminating the need for an external programming/debugging tool, two mikroBUS™ sockets for Click board™ connectivity, a USB connector, a set of indicator LEDs, push button switches and a variable potentiometer. All

these features allow you to combine the strength of Microchip and Mikroe and create custom electronic solutions more efficiently than ever. Each part of the Curiosity HPC development board contains the components necessary for the most efficient operation of the same board. An integrated onboard PICkit™ (PKOB) allows low-voltage programming and in-circuit debugging for all supported devices. When used with the MPLAB® X Integrated Development Environment (IDE, version 3.0 or higher) or MPLAB® Xpress IDE, in-circuit debugging allows users to run, modify, and troubleshoot their custom software and hardware

quickly without the need for additional debugging tools. Besides, it includes a clean and regulated power supply block for the development board via the USB Micro-B connector, alongside all communication methods that mikroBUS™ itself supports. Curiosity HPC development board allows you to create a new application in just a few steps. Natively supported by Microchip software tools, it covers many aspects of prototyping thanks to many number of different Click boards™ (over a thousand boards), the number of which is growing daily.

Curiosity HPC double image

Microcontroller Overview

MCU Card / MCU

PIC18F47Q10

Architecture

PIC

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

40

RAM (Bytes)

3615

Used MCU Pins

mikroBUS™ mapper

NC
NC
AN
NC
NC
RST
SPI Chip Select
RA3
CS
SPI Clock
RB1
SCK
SPI Data OUT
RB2
MISO
SPI Data IN
RB3
MOSI
Power Supply
3.3V
3.3V
Ground
GND
GND
NC
NC
PWM
NC
NC
INT
NC
NC
TX
NC
NC
RX
NC
NC
SCL
NC
NC
SDA
Power Supply
5V
5V
Ground
GND
GND
1

Take a closer look

Click board™ Schematic

4x4 Key Click Schematic schematic

Step by step

Project assembly

Curiosity HPC front no-mcu image hardware assembly

Start by selecting your development board and Click board™. Begin with the Curiosity HPC as your development board.

Curiosity HPC front no-mcu image hardware assembly
GNSS2 Click front image hardware assembly
MCU DIP 40 hardware assembly
Prog-cut hardware assembly
Curiosity HPC Access 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 image step 5 hardware assembly
Necto image step 6 hardware assembly
Necto DIP image step 7 hardware assembly
Necto No Display image step 8 hardware assembly
Necto image step 9 hardware assembly
Necto image step 10 hardware assembly
Debug Image Necto Step hardware assembly

Software Support

Library Description

This library contains API for 4x4 Key Click driver.

Key functions:

  • c4x4key_get_data - Get 16-bit data function.

  • c4x4key_get_btn_position - Get position pressed button 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 4x4Key Click example
 * 
 * # Description
 * The library covers all the necessary functions to control the 4x4 Key Click.
 * 4x4 Key Click communicates with the target board via SPI interface. 
 * This library contains drivers for reading data from a sensor and get 
 * the position of the pressed button.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Configuring Clicks and log objects.
 * 
 * ## Application Task  
 * This is a example which demonstrates the use of 4x4 Key Click board.
 * Detects and logs whether any of the buttons is pressed.
 * Results are being sent to the Usart Terminal
 * where you can track their changes.
 * All data logs on usb uart when the button is triggered.
 * 
 * \author Nenad Filipovic
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "c4x4key.h"

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

static c4x4key_t c4x4key;
static log_t logger;

static uint16_t btn_data_old;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    c4x4key_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.

    c4x4key_cfg_setup( &cfg );
    C4X4KEY_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    c4x4key_init( &c4x4key, &cfg );
    
    btn_data_old = 0;
    
    log_printf( &logger, "   4x4 Key Click\r\n" );
    log_printf( &logger, "--------------------\r\n" );
    log_printf( &logger, "  Press any button\r\n" );
    log_printf( &logger, "--------------------\r\n" );
}

void application_task ( void )
{
    uint16_t btn_data;
    
    btn_data = c4x4key_get_data( &c4x4key );

    if ( btn_data_old != btn_data )
    {
        if ( btn_data == C4X4KEY_BUTTON_0 )
        {
            log_printf( &logger, "         0\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_1 )
        {
            log_printf( &logger, "         1\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_2 )
        {
            log_printf( &logger, "         2\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_3 )
        {
            log_printf( &logger, "         3\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_4 )
        {
            log_printf( &logger, "         4\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_5 )
        {
            log_printf( &logger, "         5\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_6 )
        {
            log_printf( &logger, "         6\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_7 )
        {
            log_printf( &logger, "         7\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_8 )
        {
            log_printf( &logger, "         8\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_9 )
        {
            log_printf( &logger, "         9\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_A )
        {
            log_printf( &logger, "         A\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_B )
        {
            log_printf( &logger, "         B\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_C )
        {
            log_printf( &logger, "         C\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_D )
        {
            log_printf( &logger, "         D\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_STAR )
        {
            log_printf( &logger, "         *\r\n" );
        }
        
        if ( btn_data == C4X4KEY_BUTTON_HASH )
        {
            log_printf( &logger, "         #\r\n" );
        }

        btn_data_old = btn_data;
    }
    Delay_10ms();
}

int main ( void ) 
{
    /* Do not remove this line or clock might not be set correctly. */
    #ifdef PREINIT_SUPPORTED
    preinit();
    #endif
    
    application_init( );
    
    for ( ; ; ) 
    {
        application_task( );
    }

    return 0;
}


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

Additional Support

Resources

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