CLRF PORTA                       ; Initialize PORTA by clearing output data latches

CLRF LATA             ; Alternate method to clear output data latches

MOVLW 0Fh                         ; Configure A/D 
MOVWF ADCON1               ; for digital inputs

MOVLW 07h                         ; Configure comparators
MOVWF CMCON                ; for digital input

MOVLW 0CFh                      ; Value used to
; initialize data
; direction
MOVWF TRISA                    ; Set RA<3:0> as inputs
; RA<5:4> as outputs

PORTA = 0 ;                          // Initialize PORTA by clearing output data latches
LATA = 0 ;                             // Alternate method to clear output data latches
ADCON1 = 0x0F ;                 // Configure A/Dfor digital inputs(=00001111)
CMCON = 0x07 ;                  // Configure comparatorsfor digital input
TRISA = 0xCF ;                     //Value used to initialize datadirection(=11001111)
//Set RA<3:0> as inputs ,RA<5:4> as outputs

/********************************************************************
FLASHING LED
----------------------
In this project an LED is connected to bit 0 of PORT A (RA0) of a PIC18F2550 type microcontroller (any other PIC microcontroller can also be used in this project). The microcontroller is operated from an 8MHz crystal. The LED is flashed continuously with 1 second intervals.
*****************************************************************/
void main()
{

ADCON1 = 0x0F ;                 // Configure A/Dfor digital inputs(=00001111)
CMCON = 0x07 ;                  // Configure comparatorsfor digital input
TRISA = 0;                             // Configure PORT A as outputs

for(;;)                                     // FOREVER loop
{
PORTA.RA0 = 1;                  // Turn ON LED
Delay_Ms(1000);                   // Wait 1 second
PORTA.RA0 = 0;                  // Turn OFF LED
Delay_Ms(1000); // Delay 1 second
}
}