This code is for blinking a LED connected to D2 pin of PIC16F877A,MPLAB X is used as IDE and CCS compiler is used. A 20MHz external oscillator is used in circuit.

LED_Blink.c

#include "16F877A.h"

#FUSES HS
#use delay (clock=20MHZ)

void main() 
{
    set_tris_a(0x00);
    set_tris_b(0x00);
    set_tris_c(0x00);
    set_tris_d(0x00);
    output_a(0x00);
    output_b(0x00);
    output_c(0x00);
    while (1) 
    {
        output_d(0xFF);
        delay_ms(1000); //1 Second Delay
        output_d(0x00);
        delay_ms(1000); //1 Second Delay
    }
}