AVR Freaks

/************************************************************************ 
;*				---- MODIFIED ----                                                    * 
;*              Testing Read and debounce up to 8 keys                  * 
;*              Bulletproof: 4 equal samples needed                     * 
;*                                                                      * 
;*              Author: P. Dannegger                                    * 
;*                      danni@specs.de                                  * 
;*                                                                      * 
;***********************************************************************/ 
//https://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=33821&highlight=dannegger+debounce

// Danni's debounce version MODIFIED

#include 
#include 
#include 

#define KEY_INPUT       PIND	/* PINx - register for button input */
#define KEY_BIT_0		PD0     /* bit for button input/output */
#define KEY_BIT_1		PD1     /* bit for button input/output */
#define LED_OUTPUT      PORTB 
#define LED_DIR         DDRB 

char key_state_0, key_state_1;			// debounced and inverted key state: 
                                        // bit = 1: key pressed 
char key_press_0, key_press_1;			// key press detect 

/************************************************************************************************/

ISR(TIMER0_OVF_vect)					//INT0_vect		//SIGNAL (SIG_OVERFLOW0) 
{ 
  static char ct0, ct1; 
  char i; 
// INSTEAD OF KEY_INPUT, check key changed in PD0
 // i = key_state ^ ~KEY_INPUT;			// key changed ? 
	i = key_state_0 ^ ~KEY_BIT_0;
	ct0 = ~( ct0 & i );					// reset or count ct0 
	ct1 = ct0 ^ (ct1 & i);				// reset or count ct1 
	i &= ct0 & ct1;						// count until roll over ? 
	key_state_0 ^= i;					// then toggle debounced state 
										// now debouncing finished 
	key_press_0 |= key_state_0 & i;		// 0->1: key press detect 
} 
/************************************************************************************************/

ISR(TIMER1_OVF_vect)					//INT0_vect		//SIGNAL (SIG_OVERFLOW0) 
{ 
  static char ct0, ct1; 
  char i; 
// INSTEAD OF KEY_INPUT, check key changed in PD1
  i = key_state_1 ^ ~KEY_BIT_1;			// key changed ? 
  ct0 = ~( ct0 & i );					// reset or count ct0 
  ct1 = ct0 ^ (ct1 & i);				// reset or count ct1 
  i &= ct0 & ct1;						// count until roll over ? 
  key_state_1 ^= i;						// then toggle debounced state 
										// now debouncing finished 
  key_press_1 |= key_state_1 & i;		// 0->1: key press detect 
} 
/************************************************************************************************/

char get_key_press_0( char key_mask ) 
{ 
  cli(); 
  key_mask &= key_press_0;				// read key(s) 
  key_press_0 ^= key_mask;				// clear key(s) 
  sei(); 
  return key_mask; 
} 
/************************************************************************************************/

char get_key_press_1( char key_mask ) 
{ 
  cli(); 
  key_mask &= key_press_1;				// read key(s) 
  key_press_1 ^= key_mask;				// clear key(s) 
  sei(); 
  return key_mask; 
} 
/************************************************************************************************/

int main( void ) 
{ 
  	key_state_0 = 0;	key_state_1 = 0;
	key_press_0 = 0;	key_press_1 = 0;

	TCCR0 = 1<<CS02;                      //divide by 256 * 256 
	TIMSK = 1<<TOIE0;                     //enable timer interrupt 

	LED_DIR = 0xFF; 
	LED_OUTPUT = 0xFF; 
	sei(); 
	for(;;)										// main loop 
	LED_OUTPUT ^= get_key_press_0( 0xFF );		// toggle LEDs on key press 
	LED_OUTPUT ^= get_key_press_1( 0xFF );
} 

#define BUTTON_PORT PORTD       /* PORTx - register for button output */
#define BUTTON_PIN PIND         /* PINx - register for button input */
#define BUTTON_BIT PD0          /* bit for button input/output */

ISR(INT0_vect)	
{checkPinState();}

void checkPinState(void)
{
	/* the button is pressed when BUTTON_BIT is clear */
	if (bit_is_clear(BUTTON_PIN, BUTTON_BIT)) 
	{
		_delay_ms(25); // or check several times instead of the delay..?
		if (bit_is_clear(BUTTON_PIN, BUTTON_BIT)) 
		{	DebouncedButtonPushed = true;	}
		else 
		{	DebouncedButtonPushed = false;	}
	}	
}

#define KEY0 PD0 
#define LED0 PB0  

//LED_OUTPUT ^= get_key_press( 0xFF );