Blinking an LED on a microcontroller is often considered the “Hello World” program for embedded systems. It’s a great starting point for learning how to control hardware with software. This guide provides the code and circuit setup to blink an LED using the microcontroller, with the LED connected to PortA.0.

The Circuit

10F322 blink led circuit

The Code

/*
 * File:  blink_led.c
 * Author: Jamie Starling - GizoFoundry.com 
 *
 * Created on:  September 1, 2021, 9:45 AM
 * 
 * Code provided as-is.
 */


#include <xc.h>
#include <stdint.h>

//Device Configuration
#pragma config FOSC = INTOSC  // Oscillator Selection 
#pragma config BOREN = ON    // Brown-out Reset
#pragma config WDTE = OFF    // Watchdog Timer
#pragma config PWRTE = ON    // Power-up Timer
#pragma config MCLRE = OFF   // MCLR Pin Function Select bit->MCLR pin function is digital input, MCLR internally tied to VDD
#pragma config CP = OFF      // Code Protection 
#pragma config LVP = OFF     // Low-Voltage Programming 
#pragma config LPBOR = ON    // Brown-out Reset Selection bits
#pragma config BORV = LO    // Brown-out Reset Voltage Selection
#pragma config WRT = OFF    // Flash Memory Self-Write Protection

//Used to calculate the delay time - Change depending on processor Speed
#define _XTAL_FREQ 8000000  //8 MHz (default after Reset)

//Prototypes
void setup (void);
void blink_led(void);


//Main Code Entry 
void main(void)
{
    setup();  //Device Setup
    
    while(1) //Loop Here forever and do blink_led
    {
      blink_led(); 
    } //End of while
} //End of Main


void setup (void)
{
    ANSELAbits.ANSA0 = 0; //Disable Analog
    //Set Pin 0 PortA.0 as output
    TRISAbits.TRISA0 = 0;
}//End of setup


void blink_led(void)
{
    //Set PortA.0 High (turn on LED)
    LATAbits.LATA0 = 1;      
        
    //Wait 1 second - delay macro is in ms so 1000ms = 1 second
    __delay_ms(1000);
        
    //Set PortA.0 Low  (turn off LED)
    LATAbits.LATA0 = 0;
        
    //Wait 1 second
    __delay_ms(1000); 
}//End of blink_led

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