PIC12F1822 - Blink a LED __delay_ms - version

02.01.25

Embedded

This is the basic of a program to blink a LED connected to PORTbits.RA4. The LED blinks at a rate of 500ms. The program use the delay function, which isn't very good, because the MCU halts/stops for the time the delay is going on. It's much better to use interrupt.

// INCLUDE LIBRARIES
#include < xc.h >

// CONFIGURATION BITS
// CONFIG1
#pragma config FOSC     = INTOSC    // Oscillator Selection (INTOSC oscillator: I/O function on CLKIN pin)
#pragma config WDTE     = OFF       // Watchdog Timer Enable (WDT enabled)
#pragma config PWRTE    = OFF       // Power-up Timer Enable (PWRT disabled)
#pragma config MCLRE    = ON        // MCLR Pin Function Select (MCLR/VPP pin function is MCLR)
#pragma config CP       = OFF       // Flash Program Memory Code Protection (Program memory code protection is disabled)
#pragma config CPD      = OFF       // Data Memory Code Protection (Data memory code protection is disabled)
#pragma config BOREN    = ON        // Brown-out Reset Enable (Brown-out Reset enabled)
#pragma config CLKOUTEN = OFF       // Clock Out Enable (CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin)
#pragma config IESO     = ON        // Internal/External Switchover (Internal/External Switchover mode is enabled)
#pragma config FCMEN    = ON        // Fail-Safe Clock Monitor Enable (Fail-Safe Clock Monitor is enabled)

// CONFIG2
#pragma config WRT      = OFF       // Flash Memory Self-Write Protection (Write protection off)
#pragma config PLLEN    = ON        // PLL Enable (4x PLL enabled)
#pragma config STVREN   = ON        // Stack Overflow/Underflow Reset Enable (Stack Overflow or Underflow will cause a Reset)
#pragma config BORV     = LO        // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (Vbor), low trip point selected.)
#pragma config DEBUG    = OFF       // In-Circuit Debugger Mode (In-Circuit Debugger disabled, ICSPCLK and ICSPDAT are general purpose I/O pins)
#pragma config LVP      = ON        // Low-Voltage Programming Enable (Low-voltage programming enabled)

#define _XTAL_FREQ 4000000          // Reference frequency for the compiler
#define led PORTAbits.RA4           // Assign the LED to RA4

void main(void) {
    TRISA = 0;                      // Set TRISA to Output
    PORTA = 0;                      // Set PORTA to LOW
    OSCCON = 0b11101010;            // PLL enabled, 4MHz, Internal osc
           
    while (1) {
        led = 1;
        __delay_ms(500);
        led = 0;
        __delay_ms(500);    
    }
    
    return;
}

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