PIC16F684 Flashing an LED with delay_ms, TMR0, Interrupt, & WDT

The LED flashes approximately 150ms every 5 seconds. RC1 (pin 9), triggers the LED. Interestingly, the PIC consumes 28uA at idle, no matter which method is used. Compiles with Microchip’s XC8 (v1.38)

  • Delay function, 28 bytes
  • Timer 0 delay, 31 bytes
  • Timer 0 Interrupt, 60 bytes
  • WDT Sleep, 27 bytes
/*
 * File:   Delay_Blinky.c
 * January 21, 2017, 1:14 AM
 */

#include   

// CONFIG
#pragma config FOSC = INTOSCIO
#pragma config WDTE = OFF 
#pragma config PWRTE = OFF 
#pragma config MCLRE = OFF 
#pragma config CP = OFF 
#pragma config CPD = OFF 
#pragma config BOREN = OFF 
#pragma config IESO = OFF 
#pragma config FCMEN = OFF 

#define _XTAL_FREQ 31000

void main(void)
{
    //Set clock to 31KHz    
    OSCCONbits.IRCF2 = 0;
    OSCCONbits.IRCF1 = 0;
    OSCCONbits.IRCF0 = 0;

    TRISCbits.TRISC1 = 0;
    ANSEL = 0;

    while (1)
    {
        RC1 = 0;
        __delay_ms(5000);
        RC1 = 1;
        __delay_ms(150);
    }
}

/*
 * File:   TMR0_Blinky.c
 * January 21, 2017, 1:38 AM
 */

#include  

// CONFIG
#pragma config FOSC = INTOSCIO
#pragma config WDTE = OFF 
#pragma config PWRTE = OFF 
#pragma config MCLRE = OFF 
#pragma config CP = OFF 
#pragma config CPD = OFF 
#pragma config BOREN = OFF 
#pragma config IESO = OFF 
#pragma config FCMEN = OFF 

#define _XTAL_FREQ 31000

void main(void)
{
    //Set clock to 31KHz    
    OSCCONbits.IRCF2 = 0;
    OSCCONbits.IRCF1 = 0;
    OSCCONbits.IRCF0 = 0;

    TRISCbits.TRISC1 = 0;
    ANSEL = 0;

    //Reset Timer 0
    TMR0 = 0;
    //Set clock edge start and stop
    T0CS = 0;
    T0SE = 0;
    
    //Set prescaler to TMR0
    PSA = 0;
    //Set prescaler bits
    PS2 = 1;
    PS1 = 1;
    PS0 = 0;
    
    while (1)
    {
        RC1 = 0;
        while(!T0IF);
        RC1 = 1;
        __delay_ms(150);
        T0IF = 0;
    }
}
/*
 * File:   Interrupt_Blinky.c
 * January 21, 2017, 1:56 AM
 */

#include 

// CONFIG
#pragma config FOSC = INTOSCIO
#pragma config WDTE = OFF 
#pragma config PWRTE = OFF 
#pragma config MCLRE = OFF 
#pragma config CP = OFF 
#pragma config CPD = OFF 
#pragma config BOREN = OFF 
#pragma config IESO = OFF 
#pragma config FCMEN = OFF 

#define _XTAL_FREQ 31000

void main(void)
{
    //Set clock to 31KHz    
    OSCCONbits.IRCF2 = 0;
    OSCCONbits.IRCF1 = 0;
    OSCCONbits.IRCF0 = 0;

    TRISCbits.TRISC1 = 0;
    ANSEL = 0;
    
    //Reset Timer 0
    TMR0 = 0;
    //Set clock edge start and stop
    T0CS = 0;
    T0SE = 0;

    //Set prescaler to TMR0
    PSA = 0;
    //Set prescaler bits
    PS2 = 1;
    PS1 = 1;
    PS0 = 0;
    
    T0IE = 1; //Enable interrupt timer
    INTCONbits.INTE = 1; //Enable External Interrupt
    INTCONbits.GIE = 1; //Enable Global Interrupt
    CLRWDT();

    while (1);
}

void interrupt blinky(void)
{
    if (INTCONbits.T0IF && INTCONbits.T0IE)
    {
        TMR0 -= 254;
        RC1 = 1;
        __delay_ms(150);
        RC1 = 0;

        INTCONbits.T0IF = 0; //Reset Timer
    }
}
/*
 * File:   Sleep_Blinky.c
 * January 21, 2017, 2:21 AM
 */

#include  

// CONFIG
#pragma config FOSC = INTOSCIO
#pragma config WDTE = ON 
#pragma config PWRTE = OFF 
#pragma config MCLRE = OFF 
#pragma config CP = OFF 
#pragma config CPD = OFF 
#pragma config BOREN = OFF 
#pragma config IESO = OFF 
#pragma config FCMEN = OFF 

#define _XTAL_FREQ 31000

void main(void)
{
    //Set clock to 31KHz    
    OSCCONbits.IRCF2 = 0;
    OSCCONbits.IRCF1 = 0;
    OSCCONbits.IRCF0 = 0;

    TRISCbits.TRISC1 = 0;
    ANSEL = 0;

    //Set prescaler to WDT
    PSA = 1;
    //Set prescaler bits
    PS2 = 1;
    PS1 = 1;
    PS0 = 1;
    
    while(1)
    {
        RC1 = 1;
        __delay_ms(150);
        RC1 = 0;
        CLRWDT();
        SLEEP();
        CLRWDT();
        SLEEP();
    }
}

 

 

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