Home   Simple Keypad

Embedded C code for Simple Keypad


Sample code for Simple Keypad.
Following code can be using for AVR series ICs like: ATmega8, ATmega16, ATmega32. 

 

#include <avr/io.h>
#include <util/delay.h>

#ifndef cbi
#define cbi(sfr, bit) (_SFR_BYTE(sfr) &= ~_BV(bit))
#endif

#ifndef sbi
#define sbi(sfr, bit) (_SFR_BYTE(sfr) |= _BV(bit))
#endif

void initports(void);

int main(void)
{
	initports();
	
	while(1)
	{		
		if(bit_is_clear(PINA,0))
		{
			_delay_ms(5);		// debounce delay
			if(bit_is_clear(PINA,0))
			{
				cbi(PORTB,0);
				sbi(PORTB,1);
				sbi(PORTB,2);
			}
			else
			{
			}
		}			
		else
		{
		}
		if(bit_is_clear(PINA,1))
		{
			_delay_ms(5);
			if(bit_is_clear(PINA,1))
			{
				sbi(PORTB,0);
				cbi(PORTB,1);
				sbi(PORTB,2);
			}
			else
			{
			}
		}
		else
		{
		}		
		if(bit_is_clear(PINA,2))
		{
			_delay_ms(5);
			if(bit_is_clear(PINA,2))
			{
				sbi(PORTB,0);
				sbi(PORTB,1);
				cbi(PORTB,2);
			}
			else
			{
			}
		}
		else
		{
		}
	}
	return 0;
}

void initports(void)
{
	cbi(DDRA,0);	//set A.0 as input
	cbi(DDRA,1);	//set A.1 as input
	cbi(DDRA,2);	//set A.2 as input
	
	sbi(DDRB,0);	//set B.0 as output
	sbi(DDRB,1);	//set B.1 as output
	sbi(DDRB,2);	//set B.2 as output
	
	PORTB = 0xFF;	//turn off all LEDs
	
	return;
}