/* ATtiny45                            
                                 PDIP/SOIC/TSSOP
       (PCINT5/RESET(i)/ADC0/dW) PB5 [1] [8] VCC
(PCINT3/XTAL1/CLKI/OC1B(i)/ADC3) PB3 [2] [7] PB2 (SCK/USCK/SCL/ADC1/T0/INT0/PCINT2)
   (PCINT4/XTAL2/CLKO/OC1B/ADC2) PB4 [3] [6] PB1 (MISO/DO/AIN1/OC0B/OC1A/PCINT1)
                                 GND [4] [5] PB0 (MOSI/DI/SDA/AIN0/OC0A/OC1A(i)/AREF/PCINT0)
*/

#include <avr/interrupt.h>
#include <util/atomic.h>
#include <util/delay.h> 

#define F_CPU           1000000           // 1 MHz

#define KEY_PIN         PINB
#define KEY_PORT        PORTB
#define KEY0            2

#define LED_DDR         DDRB
#define LED_PORT        PORTB
#define LED0            0
//#define LED1            1
//#define LED2            4
//#define LED3            3


#define REPEAT_MASK     (1<<KEY0)       // repeat: key0
#define REPEAT_START    50              // after 500ms
#define REPEAT_NEXT     20              // every 200ms

uint8_t key_state;                      // debounced and inverted key state:
                                        // bit = 1: key pressed
uint8_t key_press;                      // key press detect
uint8_t key_release;                    // key release detect
uint8_t key_rpt;                        // key long press and repeat

uint8_t direction = 1;                  // Dimmrichtung
uint8_t pressed = 0;                    // Taste gedrückt
uint8_t pwm = 0;                        // Dimmer Zustand

ISR( TIMER1_COMPA_vect )                          // every 10ms (Timer1)
{
  static uint8_t ct0 = 0xFF, ct1 = 0xFF, rpt;
  uint8_t i;

  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
  key_release |= ~key_state & i;                // 1->0: key release 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;
  }
}

uint8_t get_key_press( uint8_t key_mask )
{
  ATOMIC_BLOCK(ATOMIC_FORCEON){
    key_mask &= key_press;                      // read key(s)
    key_press ^= key_mask;                      // clear key(s)
  }
  return key_mask;
}

uint8_t get_key_rpt( uint8_t key_mask )
{
  ATOMIC_BLOCK(ATOMIC_FORCEON){
    key_mask &= key_rpt;                        // read key(s)
    key_rpt ^= key_mask;                        // clear key(s)
  }
  return key_mask;
}

uint8_t get_key_short( uint8_t key_mask )
{
  uint8_t i;

  ATOMIC_BLOCK(ATOMIC_FORCEON)
    i = get_key_press( ~key_state & key_mask );
  return i;
}

uint8_t get_key_long( uint8_t key_mask )
{
  return get_key_press( get_key_rpt( key_mask ));
}

uint8_t get_key_long_r( uint8_t key_mask )      // if repeat function needed
{
  return get_key_press( get_key_rpt( key_press & key_mask ));
}

uint8_t get_key_rpt_l( uint8_t key_mask )       // if long function needed
{
  return get_key_rpt( ~key_press & key_mask );
}

int main( void )
{
  /* Taster Entprellen über Timer nach Peter Danegger */
  TCCR1  = 1<<CTC1 | 1<<CS13 | 1<<CS11 | 1<<CS10;      // Mode 2. CTC1 (Timer1)
                                                       // F_CPU / 1024 (Timer1)
  OCR1C  = F_CPU / 1024.0 * 10e-3 + 0.5;               // 10ms interrupt (Timer1)
  TIMSK  = 1<<OCIE1A;						           // (Timer1)

  LED_DDR   = 1<<LED0;
  KEY_PORT |= (1<<KEY0);                                  // Pullup on
  
   /* PWM für Dimmer */
  TCCR0A  = ( 1 << COM0A1 ) | ( 1 << WGM00 ) | ( 1 << WGM01 ); // Clear OC0A/OC0B on Compare Match
                                                               // Fast PWM , TOP = 0xFF
  TCCR0B  = ( 1 << CS01 ) | ( 1 << CS00 ); // Mode: Normal | F_Proz/64 (From prescaler)
  OCR0A = 0;  // LED aus
  
  sei();
  
  for(;;){                                              // main loop
    
    if( (get_key_short( 1<<KEY0 )))
      if(pwm > 0)
         pwm = 0;
      else
         pwm = 255;

    if( get_key_long_r( 1<<KEY0 ) || get_key_rpt_l( 1<<KEY0 ))
      {
      pressed = 1;
      if( direction )
        {
          if( pwm < 255 )
              ++pwm;
        }
      else
        {
          if( pwm > 0 )
              --pwm;
        }
    }
    else if( pressed )
      {
         pressed = 0;
         direction = 1 - direction;
      }  
   OCR0A = pwm;
   //_delay_ms(10);
  }
  return 0;
}