#include <io.h>
#include <alcd.h>
#include <stdio.h>
#include <stdint.h>

#define RF_PIN                  PIND.2


#define IS_SYNC(ON, OFF)        (OFF > (ON * 25) && OFF < (ON * 35))
#define IS_ZERO(ON, OFF)        (OFF > (ON * 2) && OFF < (ON * 4))
#define IS_ONE(ON, OFF)         (ON > (OFF * 2) && ON < (OFF * 4))

uint8_t rfReady = 0;
uint8_t rfBitCount = 0;
uint16_t rfHighDuty = 0;
uint16_t rfLowDuty = 0;
uint32_t rfTempCode = 0;
// 24Bit -> 20Bit Address (Fix) - 4Bit Keys (Variable)
uint32_t rfCode = 0;


// External Interrupt 0 service routine
interrupt [EXT_INT0] void ext_int0_isr(void)
{
  if (RF_PIN == 0) {
    // falling-edge  -> ----|___
    rfHighDuty = TCNT1;
  }                    
  else {
    // rising-edge   -> ____|-----
    rfLowDuty = TCNT1;
    if (rfBitCount == 0) {
      if (IS_SYNC(rfHighDuty, rfLowDuty)) {
        rfBitCount = 1;
        rfTempCode = 0;
      }
    }                  
    else {      
      // MSB-First
      rfTempCode <<= 1;
      rfBitCount++;
      
      if (IS_ONE(rfHighDuty, rfLowDuty)) {
        rfTempCode |= 1;
      } 
      else if (!IS_ZERO(rfHighDuty, rfLowDuty)) {
        rfBitCount = 0;
      }                
      
      if (rfBitCount > 24) {
        rfCode = rfTempCode;     
        rfBitCount = 0;
        rfReady = 1;
      }
    }
  }        
  TCNT1 = 0;
}

void main(void)
{
// Declare your local variables here
char str[17];
// Input/Output Ports initialization
// Port A initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRA=(0<<DDA7) | (0<<DDA6) | (0<<DDA5) | (0<<DDA4) | (0<<DDA3) | (0<<DDA2) | (0<<DDA1) | (0<<DDA0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTA=(0<<PORTA7) | (0<<PORTA6) | (0<<PORTA5) | (0<<PORTA4) | (0<<PORTA3) | (0<<PORTA2) | (0<<PORTA1) | (0<<PORTA0);

// Port B initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRB=(0<<DDB7) | (0<<DDB6) | (0<<DDB5) | (0<<DDB4) | (0<<DDB3) | (0<<DDB2) | (0<<DDB1) | (0<<DDB0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTB=(0<<PORTB7) | (0<<PORTB6) | (0<<PORTB5) | (0<<PORTB4) | (0<<PORTB3) | (0<<PORTB2) | (0<<PORTB1) | (0<<PORTB0);

// Port C initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRC=(0<<DDC7) | (0<<DDC6) | (0<<DDC5) | (0<<DDC4) | (0<<DDC3) | (0<<DDC2) | (0<<DDC1) | (0<<DDC0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTC=(0<<PORTC7) | (0<<PORTC6) | (0<<PORTC5) | (0<<PORTC4) | (0<<PORTC3) | (0<<PORTC2) | (0<<PORTC1) | (0<<PORTC0);

// Port D initialization
// Function: Bit7=In Bit6=In Bit5=In Bit4=In Bit3=In Bit2=In Bit1=In Bit0=In 
DDRD=(0<<DDD7) | (0<<DDD6) | (0<<DDD5) | (0<<DDD4) | (0<<DDD3) | (0<<DDD2) | (0<<DDD1) | (0<<DDD0);
// State: Bit7=T Bit6=T Bit5=T Bit4=T Bit3=T Bit2=T Bit1=T Bit0=T 
PORTD=(0<<PORTD7) | (0<<PORTD6) | (0<<PORTD5) | (0<<PORTD4) | (0<<PORTD3) | (0<<PORTD2) | (0<<PORTD1) | (0<<PORTD0);

// Timer/Counter 1 initialization
// Clock source: System Clock
// Clock value: 1000.000 kHz
// Mode: Normal top=0xFFFF
// OC1A output: Disconnected
// OC1B output: Disconnected
// Noise Canceler: Off
// Input Capture on Falling Edge
// Timer Period: 65.536 ms
// Timer1 Overflow Interrupt: Off
// Input Capture Interrupt: Off
// Compare A Match Interrupt: Off
// Compare B Match Interrupt: Off
TCCR1A=(0<<COM1A1) | (0<<COM1A0) | (0<<COM1B1) | (0<<COM1B0) | (0<<WGM11) | (0<<WGM10);
TCCR1B=(0<<ICNC1) | (0<<ICES1) | (0<<WGM13) | (0<<WGM12) | (0<<CS12) | (1<<CS11) | (0<<CS10);
TCNT1H=0x00;
TCNT1L=0x00;
ICR1H=0x00;
ICR1L=0x00;
OCR1AH=0x00;
OCR1AL=0x00;
OCR1BH=0x00;
OCR1BL=0x00;

// Timer(s)/Counter(s) Interrupt(s) initialization
TIMSK=(0<<OCIE2) | (0<<TOIE2) | (0<<TICIE1) | (0<<OCIE1A) | (0<<OCIE1B) | (0<<TOIE1) | (0<<OCIE0) | (0<<TOIE0);

// External Interrupt(s) initialization
// INT0: On
// INT0 Mode: Any change
// INT1: Off
// INT2: Off
GICR|=(0<<INT1) | (1<<INT0) | (0<<INT2);
MCUCR=(0<<ISC11) | (0<<ISC10) | (0<<ISC01) | (1<<ISC00);
MCUCSR=(0<<ISC2);
GIFR=(0<<INTF1) | (1<<INTF0) | (0<<INTF2);

// Alphanumeric LCD initialization
// Connections are specified in the
// Project|Configure|C Compiler|Libraries|Alphanumeric LCD menu:
// RS - PORTA Bit 0
// RD - PORTA Bit 1
// EN - PORTA Bit 2
// D4 - PORTA Bit 4
// D5 - PORTA Bit 5
// D6 - PORTA Bit 6
// D7 - PORTA Bit 7
// Characters/line: 16
lcd_init(16);

// Global enable interrupts
#asm("sei")

while (1)
      {
        if (rfReady) {
          rfReady = 0;
          sprintf(str, "%06lX", rfCode);
          lcd_gotoxy(0, 0);
          lcd_puts(str);
        }
      }
}
