Klávesnica 2x3: Rozdiel medzi revíziami

// Zahrnutie kniznic
#include <avr/io.h>
#include "uart.h"

#include <stdio.h>
FILE mystdout = FDEV_SETUP_STREAM(uart_putc, NULL, _FDEV_SETUP_WRITE);

// Definovanie tlacidok na piny formou matice
const uint8_t button_pins[2][3] = {
    {2, 3, 4}, // Rad 1
    {5, 6, 7}  // Rad 2
};

#define LED_PIN PB5	// Definovanie pinu PB5 na vnutornu LEDku

// Inicializacia pinov ako vstupy, pull-up resistor zapnuty
void init_buttons() {
    for (int i = 0; i < 2; i++) {	// Citanie pinov formou matice
        for (int j = 0; j < 3; j++) {
            DDRD &= ~(1 << button_pins[i][j]);	
            PORTD |= (1 << button_pins[i][j]);
        }
    }
	DDRB |= (1 << LED_PIN);	// Nastav LED pin ako output
}

// Funkcia na citanie stlaceneho tlacidka
char scan_buttons() {
    static char last_button = '\0';				// Zapamataj si naposledy stlacene tlacidko
	if (!(PIND & (1 << button_pins[0][0]))){	// Pri stlaceni 1 vrat 1
		return '1';
	}
    
    // Skenuj kazde tlacidko dokym nenajdes jedno stlacene
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 3; j++) {
            if (!(PIND & (1 << button_pins[i][j]))) {	
                // Nasiel stlacene tlacidko
				char button = '1' + i*3 + j;	// Vypocet cisla tlacidka podla pinu
                if (last_button != button) {
					last_button = button;
					return last_button;			// Ak sa naposledy stlacene tlacidko nerovna momentalne stlacenemu, prepis to
                }
            }
        }
    }
    
    // Ziadne tlacidko nebolo stlacene, zresetuj last_button a vrat '\0'
    last_button = '\0';
    
    return '\0';
}

                              
int main(void)
{
  // Inicializacia kniznic
  hw_init();
  uart_init();
  
  init_buttons();
  
  stdout = &mystdout;
  
    while (1) {
        char button = scan_buttons();			// Skenuj stlacenie tlacidok v nekonecnej slucke a zapis do button
        if (button == '1') {					// Ked identifikoval 1, zapni LED
			PORTB |= (1 << LED_PIN);
        }
		else {
			PORTB &= ~(1 << LED_PIN);			// Ak nie je stlacena 1, vypni LED
		}
        if (button != '\0'){					// Ak je nejake tlacidko stlacene, vypis jeho cislo do Serial
			printf("%c\n", button);
			delay(170);							// Delay na debouncenutie tlacidka
		}								
    }
  
  return(0);
}