unsigned char FlagReg;
sbit ZC at FlagReg.B0;

void interrupt(){
     if (INTCON.INTF){          //INTF flag raised, so external interrupt occured
        ZC = 1;
        INTCON.INTF = 0;
     }
}

void main() {
     PORTB = 0;
     TRISB = 0x01;              //RB0 input for interrupt
     PORTD = 0;
     TRISD = 0;                 //PORTD all output
     OPTION_REG.INTEDG = 0;      //interrupt on falling edge
     INTCON.INTF = 0;           //clear interrupt flag
     INTCON.INTE = 1;           //enable external interrupt
     INTCON.GIE = 1;            //enable global interrupt

     while (1){
           if (ZC){ //zero crossing occurred
              delay_ms(2);
              PORTD.B0 = 1; //Send a pulse
              delay_us(250);
              PORTD.B0 = 0;
              ZC = 0;
           }
     }
}

// global variables.
unsigned short PWM=41, COUNT=0; 
// Interrupt function.
void interrupt() 
{ 
// External interruption by RB0.at each zero crossing
if( INTCON.F1 ) 
{ 
// The trigger pin is turned off.
PORTB.F7=0; 
// The counter is reset.
COUNT = 0; 
// The external interrupt flag goes out.
INTCON.F1=0; 
} 
// Interruption by Timer 0 each 102.4u sec .
if( INTCON.F2 ) 
{ 
// The counter is incremented.
COUNT ++; 
// The counter is compared with PWM ,
// if counter is higher ,  the trigger is turned on . 
if( COUNT > PWM )PORTB.F7=1; 
// The Timer 0  interrupt flag is switched off . 
INTCON.F2 =0; 
} 
} 
void main( void ) 
{ 
// Port configuration.
TRISB = 0b01111111; 
PORTB = 0; 
// Activation of Timer0, and external interrupt bits. 
OPTION_REG = 0b01000000; 
INTCON = 0b10110000; 
while( 1 )// Infinite loop. 
{
// Lower power push button. 
while( Button( &PORTB, 1, 10, 0 ) ) 
{ 
// Increment of the phase cut. 
PWM ++; if( PWM > 84 )PWM=84; 
delay_ms(10); // Delay of change. 
} 
// higher power  push button. 
while( Button( &PORTB, 2, 10, 0 ) ) 
{ 
// Decrement of the phase cut. 
PWM --; if( PWM == 255 )PWM=0; 
delay_ms(10); // Delay of change.
} 
} 
}

void main( void )
{
	//Configuring the USART module at 2400 bps.
	UART1_Init(2400);
	//Configuring PWM carrier frequency to create a 38K Hz
	PWM1_Init(38000);
	PWM1_Start();
	//sets the PWM duty cycle at 50%.
	PWM1_Set_Duty(127);
	while(1) //Infinite Loop.
	{
		//Transmits information in a fixed text.
		UART1_Write_Text("Infrared data transmission.");
		//sends the characters enter and carriage return.
		UART1_Write(13);
		UART1_Write(10);
		//Transmits information in a fixed text.
		UART1_Write_Text("This emission is modulated at 38KHz.");
		UART1_Write(13);
		UART1_Write(10);
		//Transmits information in a fixed text.
		UART1_Write_Text("With a transmission rate of 2400 bps.");
		//sends the characters enter and carriage return.
		UART1_Write(13);
		UART1_Write(10);
		//sends the characters enter and carriage return.
		UART1_Write(13);
		UART1_Write(10);
		// pauses for  200m seconds.
		delay_ms(200);
	}
}

void main( void )
{
	//Declaration of variables.
    	unsigned short DATA;
    	//Port settings.
    	TRISB = 0b11111110;
	PORTB = 0; 	//MAX485 is configured as a receiver.
	//Activated pull-up resistors.
	OPTION_REG = 0;
	//USART module is configured to 250000 bps.
	UART1_Init(250000);
	//PWM module is configured with a frequency of 1K Hz
	PWM1_Init(1000);
	//PWM module starts with 0%.
	PWM1_Start();
	PWM1_Set_Duty(0);

	while(1) //Infinite Loop.
	{
		//Evaluates if a data has arrived.
		if( UART1_Data_Ready() )
		{
			DATA = UART1_Read();
			//Evaluates whether the data arrival equals the flag 170.
			if( DATA==170 )
			{
			//waits for the next data.
			while( !UART1_Data_Ready() );
			DATA = UART1_Read();
			//Updates the duty cycle of the PWM.
			PWM1_Set_Duty(DATA);
			}
		}

		//Evaluates whether the button was pressed.
		if( Button(&PORTB, 1, 50, 0) )
		{
			PORTB = 1; //MAX485 is configured as a transmitter.
			//Reads the analog channel with voltage
			//potentiometer, and saved the 8 most significant bits
			// in the variable DATA.
			DATA = (ADC_Read(0)>>2)&0xFF;
			//Transmits the flag 170, to synchronize communication.
			UART1_Write(170);
			//Pauses for 1 m seconds between data.
			delay_ms(1);
			//Transmitting the value of the variable DATA.
			UART1_Write(DATA);
			//Wait until the button is released.
			while( Button(&PORTB, 1, 50, 0) );
			PORTB = 0; //Set MAX485 as receiver .
		}
	}
}

// Clear Global Interrupt Bit (GIE) 
INTCON.GIE = 0;

// Set Global Interrupt Bit (GIE) 
GIE_bit = 1;

sbit LED at PORTB.B0; // this is where LED is fully defined

#define LED PORTB.B0