Our purpose is to maximize functionality while minimizing complexity with our 4-in-1 button integration
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Hardware Overview
How does it work?
2x2 Key Click is based on the 2x2 button keyboard with debounce circuit, composed of the 74HC32, a quad 2-input OR gate from Nexperia, and the SN74HC14, a Hex Schmitt-Trigger inverter from Texas Instruments. In electronics, two metal components bounce or create multiple signals when they are in contact with each other — like when you push a button — before they reach a stable state. You want a single contact to be recorded, but the microcontroller records this as if you pressed the button many times. So debouncing is, as the name states, the removal of bounces or spikes of low and high voltages.
Graphically speaking, you want a clean line, not spikes. A debounce circuit makes sure that there are no voltage changes on the output. Thanks to it, one button press is recorded as such. All four Schmitt-trigger outputs are connected to the logic OR gate 74HC32 input pins, whose output is directly connected to the INT pin on mikroBUS. This pin is used to signalize an interrupt to the MCU any time a button is pressed. This way, the MCU software can be implemented as a simple polling routine without any delays programmed in the code (like it would be necessary if there weren’t a hardware debouncing circuit present).
Thanks to the INT pin, you can easily program a common interrupt service routine to detect when a button is pressed (the state of the button changes from low to high logic level). 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.
Features overview
Development board
Fusion for TIVA v8 is a development board specially designed for the needs of rapid development of embedded applications. It supports a wide range of microcontrollers, such as different 32-bit ARM® Cortex®-M based MCUs from Texas Instruments, regardless of their number of pins, and a broad set of unique functions, such as the first-ever embedded debugger/programmer over a WiFi network. 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, Fusion for TIVA v8 provides a fluid and immersive working experience, allowing access
anywhere and under any circumstances at any time. Each part of the Fusion for TIVA v8 development board contains the components necessary for the most efficient operation of the same board. An advanced integrated CODEGRIP programmer/debugger module offers many valuable programming/debugging options, including support for JTAG, SWD, and SWO Trace (Single Wire Output)), and seamless integration with the Mikroe software environment. Besides, it 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 HOST/DEVICE, CAN (on the MCU card, if supported), and Ethernet is also included. In addition, it also has the well-established mikroBUS™ standard, a standardized socket for the MCU card (SiBRAIN standard), and two display options for the TFT board line of products and character-based LCD. Fusion for TIVA 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
![default](https://cdn.mikroe.com/rent-a-product/request-setup/mcu-cards/mcu-card-for-tiva-tm4c1294nczad.png)
Type
8th Generation
Architecture
ARM Cortex-M4
MCU Memory (KB)
1024
Silicon Vendor
Texas Instruments
Pin count
212
RAM (Bytes)
262144
Used MCU Pins
mikroBUS™ mapper
Take a closer look
Schematic
![2x2 Key Click Schematic schematic](https://dbp-cdn.mikroe.com/catalog/click-boards/resources/1ee790a3-74b8-6fb6-bade-0242ac120009/schematic.webp)
Step by step
Project assembly
Track your results in real time
Application Output
After pressing the "FLASH" button on the left-side panel, it is necessary to open the UART terminal to display the achieved results. By clicking on the Tools icon in the right-hand panel, multiple different functions are displayed, among which is the UART Terminal. Click on the offered "UART Terminal" icon.
![UART Application Output Step 1](https://dbp-cdn.mikroe.com/cms/shared-resources/1eed703a-40a0-6b58-88de-02420a00029a/UART-AO-Step-1.jpg)
Once the UART terminal is opened, the window takes on a new form. At the top of the tab are two buttons, one for adjusting the parameters of the UART terminal and the other for connecting the UART terminal. The tab's lower part is reserved for displaying the achieved results. Before connecting, the terminal has a Disconnected status, indicating that the terminal is not yet active. Before connecting, it is necessary to check the set parameters of the UART terminal. Click on the "OPTIONS" button.
![UART Application Output Step 2](https://dbp-cdn.mikroe.com/cms/shared-resources/1eed703a-eb29-62fa-ba91-02420a00029a/UART-AO-Step-2.jpg)
In the newly opened UART Terminal Options field, we check if the terminal settings are correct, such as the set port and the Baud rate of UART communication. If the data is not displayed properly, it is possible that the Baud rate value is not set correctly and needs to be adjusted to 115200. If all the parameters are set correctly, click on "CONFIGURE".
![UART Application Output Step 3](https://dbp-cdn.mikroe.com/cms/shared-resources/1eed703b-7543-6fbc-9c69-0242ac120003/UART-AO-Step-3.jpg)
The next step is to click on the "CONNECT" button, after which the terminal status changes from Disconnected to Connected in green, and the data is displayed in the Received data field.
![UART Application Output Step 4](https://dbp-cdn.mikroe.com/cms/shared-resources/1eed703c-068c-66a4-a4fc-0242ac120003/UART-AO-Step-4.jpg)
Software Support
Library Description
This library contains API for 2x2 Key Click driver.
Key functions:
c2x2key_t1_state
- This function gets state of AN pinc2x2key_t2_state
- This function gets state of RST pinc2x2key_t3_state
- This function gets state of CS pinc2x2key_t4_state
- This function gets state of PWM pin
Open Source
Code example
This example can be found in NECTO Studio. Feel free to download the code, or you can copy the code below.
/*!
* \file
* \brief 2x2 key Click example
*
* # Description
* 2x2 Key click has a 4 button keypad and allows multiple key presses.
*
* The demo application is composed of two sections :
*
* ## Application Init
* Application Init performs Logger and Click initialization.
*
* ## Application Task
* This example code demonstrates the usage of 2X2 Key Click board.
* Detects whether any of the keys is pressed where results are being sent
* to the UART terminal where you can track changes.
*
* \author Mihajlo Djordjevic
*
*/
// ------------------------------------------------------------------- INCLUDES
#include "board.h"
#include "log.h"
#include "c2x2key.h"
uint8_t t1_state = 0;
uint8_t t1_state_old = 1;
uint8_t t2_state = 0;
uint8_t t2_state_old = 1;
uint8_t t3_state = 0;
uint8_t t3_state_old = 1;
uint8_t t4_state = 0;
uint8_t t4_state_old = 1;
// ------------------------------------------------------------------ VARIABLES
static c2x2key_t c2x2key;
static log_t logger;
// ------------------------------------------------------- ADDITIONAL FUNCTIONS
// ------------------------------------------------------ APPLICATION FUNCTIONS
void application_init ( void )
{
log_cfg_t log_cfg;
c2x2key_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_printf( &logger, "-- Application Init --\r\n" );
Delay_ms ( 1000 );
// Click initialization.
c2x2key_cfg_setup( &cfg );
C2X2KEY_MAP_MIKROBUS( cfg, MIKROBUS_1 );
c2x2key_init( &c2x2key, &cfg );
log_printf( &logger, "-----------------------\r\n" );
log_printf( &logger, " 2X2 key Click \r\n" );
log_printf( &logger, "-----------------------\r\n" );
Delay_ms ( 1000 );
log_printf( &logger, " System is ready \r\n" );
log_printf( &logger, "-----------------------\r\n" );
Delay_ms ( 1000 );
}
void application_task ( void )
{
t1_state = c2x2key_t1_state( &c2x2key );
if ( ( t1_state == 1 ) && ( t1_state_old == 0 ) )
{
log_printf( &logger, "-----------------------\r\n" );
log_printf( &logger, " Key 1 pressed \r\n" );
log_printf( &logger, "-----------------------\r\n" );
t1_state_old = 1;
}
if ( ( t1_state == 0 ) && ( t1_state_old == 1 ) )
{
t1_state_old = 0;
}
t2_state = c2x2key_t2_state( &c2x2key );
if ( ( t2_state == 1 ) && ( t2_state_old == 0 ) )
{
log_printf( &logger, "-----------------------\r\n" );
log_printf( &logger, " Key 2 pressed \r\n" );
log_printf( &logger, "-----------------------\r\n" );
t2_state_old = 1;
}
if ( ( t2_state == 0 ) && ( t2_state_old == 1 ) )
{
t2_state_old = 0;
}
t3_state = c2x2key_t3_state( &c2x2key );
if ( ( t3_state == 1 ) && ( t3_state_old == 0 ) )
{
log_printf( &logger, "-----------------------\r\n" );
log_printf( &logger, " Key 3 pressed \r\n" );
log_printf( &logger, "-----------------------\r\n" );
t3_state_old = 1;
}
if ( ( t3_state == 0 ) && ( t3_state_old == 1 ) )
{
t3_state_old = 0;
}
t4_state = c2x2key_t4_state( &c2x2key );
if ( ( t4_state == 1 ) && ( t4_state_old == 0 ) )
{
log_printf( &logger, "-----------------------\r\n" );
log_printf( &logger, " Key 4 pressed \r\n" );
log_printf( &logger, "-----------------------\r\n" );
t4_state_old = 1;
}
if ( ( t4_state == 0 ) && ( t4_state_old == 1 ) )
{
t4_state_old = 0;
}
}
void main ( void )
{
application_init( );
for ( ; ; )
{
application_task( );
}
}
// ------------------------------------------------------------------------ END