/************************************************************************/
/* */
/* Debouncing 8 Keys */
/* Sampling 4 Times */
/* With Repeat Function */
/* */
/* Author: Peter Dannegger */
/* danni@specs.de */
/* */
/************************************************************************/
#include <stdint.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#ifndef F_CPU
#define F_CPU 1000000 // processor clock frequency
#warning kein F_CPU definiert
#endif
#define KEY_DDR DDRB
#define KEY_PORT PORTB
#define KEY_PIN PINB
#define KEY0 0
#define KEY1 1
#define KEY2 2
#define ALL_KEYS (1<<KEY0 | 1<<KEY1 | 1<<KEY2)
#define REPEAT_MASK (1<<KEY1 | 1<<KEY2) // repeat: key1, key2
#define REPEAT_START 50 // after 500ms
#define REPEAT_NEXT 20 // every 200ms
#define LED_DDR DDRA
#define LED_PORT PORTA
#define LED0 0
#define LED1 1
#define LED2 2
volatile uint8_t key_state; // debounced and inverted key state:
// bit = 1: key pressed
volatile uint8_t key_press; // key press detect
volatile uint8_t key_rpt; // key long press and repeat
ISR( TIMER0_OVF_vect ) // every 10ms
{
static uint8_t ct0, ct1, rpt;
uint8_t i;
TCNT0 = (uint8_t)(int16_t)-(F_CPU / 1024 * 10e-3 + 0.5); // preload for 10ms
i = key_state ^ ~KEY_PIN; // 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 ^= i; // then toggle debounced state
key_press |= key_state & i; // 0->1: key press detect
if( (key_state & REPEAT_MASK) == 0 ) // check repeat function
rpt = REPEAT_START; // start delay
if( --rpt == 0 ){
rpt = REPEAT_NEXT; // repeat delay
key_rpt |= key_state & REPEAT_MASK;
}
}
///////////////////////////////////////////////////////////////////
//
// check if a key has been pressed. Each pressed key is reported
// only once
//
uint8_t get_key_press( uint8_t key_mask )
{
cli(); // read and clear atomic !
key_mask &= key_press; // read key(s)
key_press ^= key_mask; // clear key(s)
sei();
return key_mask;
}
///////////////////////////////////////////////////////////////////
//
// check if a key has been pressed long enough such that the
// key repeat functionality kicks in. After a small setup delay
// the key is reported beeing pressed in subsequent calls
// to this function. This simulates the user repeatedly
// pressing and releasing the key.
//
uint8_t get_key_rpt( uint8_t key_mask )
{
cli(); // read and clear atomic !
key_mask &= key_rpt; // read key(s)
key_rpt ^= key_mask; // clear key(s)
sei();
return key_mask;
}
///////////////////////////////////////////////////////////////////
//
uint8_t get_key_short( uint8_t key_mask )
{
cli(); // read key state and key press atomic !
return get_key_press( ~key_state & key_mask );
}
///////////////////////////////////////////////////////////////////
//
uint8_t get_key_long( uint8_t key_mask )
{
return get_key_press( get_key_rpt( key_mask ));
}
int main( void )
{
KEY_DDR &= ~ALL_KEYS; // konfigure key port for input
KEY_PORT |= ALL_KEYS; // and turn on pull up resistors
TCCR0 = (1<<CS02)|(1<<CS00); // divide by 1024
TIMSK |= 1<<TOIE0; // enable timer interrupt
LED_PORT = 0xFF;
LED_DDR = 0xFF;
sei();
while(1){
if( get_key_short( 1<<KEY1 ))
LED_PORT ^= 1<<LED1;
if( get_key_long( 1<<KEY1 ))
LED_PORT ^= 1<<LED2;
// single press and repeat
if( get_key_press( 1<<KEY2 ) || get_key_rpt( 1<<KEY2 )){
uint8_t i = LED_PORT;
i = (i & 0x07) | ((i << 1) & 0xF0);
if( i < 0xF0 )
i |= 0x08;
LED_PORT = i;
}
}
}
нажатие кнопки, в течение определенного интервала
Aug 19 2010, 08:35
