GPIO Registers

PORT	Direction Register	Number of Pins	Alternative Function
PORTA	TRISA	6 (PA0-PA5)	ADC
PORTB	TRISB	8 (PB0-PB7)	Interrupts
PORTC	TRISC	8 (PC0-PC7)	UART,I2C,PWM
PORTD	TRISD	8 (PD0-PD7)	Parallel Slave Port
PORTE	TRISE	3 (PE0-PB2)	ADC

Hardware Connection:

LED On Off Control with Pushbutton using PIC16f877a

Program:

/*
* File:   2_LedOnOffWithPushButton.c
* Author: Udaya
* LedOnOffWithPushButton
*
* Circuit connection
* RD6- Connected to LED as OUTPUT
* RC0- Connected to Pushbutton/SPDT switch to on/off control
*
* Created on June 3, 2019, 2:23 PM
*/

#define _XTAL_FREQ 8000000

#pragma config FOSC = HS     // Oscillator Selection bits (RC oscillator)
#pragma config WDTE = OFF        // Watchdog Timer Enable bit (WDT enabled)
#pragma config PWRTE = OFF      // Power-up Timer Enable bit (PWRT disabled)
#pragma config BOREN = OFF       // Brown-out Reset Enable bit (BOR enabled)
#pragma config LVP = OFF         // Low-Voltage (Single-Supply) In-Circuit Serial Programming Enable bit (RB3/PGM pin has PGM function; low-voltage programming enabled)
#pragma config CPD = OFF        // Data EEPROM Memory Code Protection bit (Data EEPROM code protection off)
#pragma config WRT = OFF        // Flash Program Memory Write Enable bits (Write protection off; all program memory may be written to by EECON control)
#pragma config CP = OFF         // Flash Program Memory Code Protection bit (Code protection off)

// #pragma config statements should precede project file includes.
// Use project enums instead of #define for ON and OFF.

#include <xc.h>

void delay(k)
{                                //delay function
    unsigned int i,j;
    for(i=0;i<k;i++)
    {
        for(j=0;j<100;j++);
    }
}
int main()
{
    TRISD6 = 0;
    TRISC0 = 1;
    while(1)
    {
        if(RC0 = 1)
        {
            RD6 =1;
            delay(100);
        }
        else
        {
            RD6 = 0;
            delay(100);
        }
    }

}