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Gpio not turning high in led blink program

Hi all iam new to pic12f675.trying to implement led blink program
But Gpio not turning high
kindly review the code below and please guide

#pragma config FOSC = INTRCIO // Oscillator Selection bits (INTOSC oscillator: I/O function on GP4/OSC2/CLKOUT pin, I/O function on GP5/OSC1/CLKIN)
#pragma config WDTE = OFF // Watchdog Timer Enable bit (WDT disabled)
#pragma config PWRTE = OFF // Power-Up Timer Enable bit (PWRT disabled)
#pragma config MCLRE = ON // GP3/MCLR pin function select (GP3/MCLR pin function is digital I/O, MCLR internally tied to VDD)
#pragma config BOREN = OFF // Brown-out Detect Enable bit (BOD disabled)
#pragma config CP = OFF // Code Protection bit (Program Memory code protection is disabled)
#pragma config CPD = OFF // Data Code Protection bit (Data memory code protection is disabled)

#include <xc.h>
#define _XTAL_FREQ 4000000
void main(void) {
TRISIO = 0x00;//set led as o/p
ANSEL = 0x00;//for setting digital i/o
CMCON = 0x07;
VRCON = 0x00;
ADCON0 = 0x00;
GPIO = 0;
// INTCON.PIE=0;
while(1)
{

GP2 = 1;// setting port as 1
__delay_ms(2000);
GP2 = 1;// setting port as 1
__delay_ms(2000);

}

return;
}
 

sagor1

Active Member
TRISIO, ANSEL and CMCON are all correct. I find no need for VRCON or ADCON0 as those are turned off.
Is GP2 a valid identifier, or should it be GPIO.2 ?
 

Reloadron

Well-Known Member
Most Helpful Member
Code:
GP2 = 1;// setting port as 1
__delay_ms(2000);
GP2 = 1;// setting port as 1
__delay_ms(2000);

Looks like you are turning on GP2 and then doing the same after 2 sec delay. If you want GP2 low you want it like this:
Code:
GP2 = 1;// setting port as 1
__delay_ms(2000);
GP2 = 0;// setting port as 0
__delay_ms(2000);

GP2 is High for 2 seconds then Low for 2 seconds over and over again.

Ron
 

Nigel Goodwin

Super Moderator
Most Helpful Member
TRISIO, ANSEL and CMCON are all correct. I find no need for VRCON or ADCON0 as those are turned off.
Is GP2 a valid identifier, or should it be GPIO.2 ?
I cut and pasted the code into MPLABX, and it compiles fine - so presumably GP2 is perfectly acceptable?.
Code:
GP2 = 1;// setting port as 1
__delay_ms(2000);
GP2 = 1;// setting port as 1
__delay_ms(2000);

Looks like you are turning on GP2 and then doing the same after 2 sec delay. If you want GP2 low you want it like this:
Code:
GP2 = 1;// setting port as 1
__delay_ms(2000);
GP2 = 0;// setting port as 0
__delay_ms(2000);

GP2 is High for 2 seconds then Low for 2 seconds over and over again.

Ron
I noticed that as well, but I presumed he'd changed it because he can't get GP2 to go high?, and this was a desperate attempt to try and make it so - personally I'd have simply commented out all but the first of the four lines.
 

Ian Rogers

User Extraordinaire
Forum Supporter
Most Helpful Member
#pragma config MCLRE = ON // GP3/MCLR pin function select (GP3/MCLR pin function is digital I/O, MCLR internally tied to VDD)
This is worded wrong MCLRE = ON means you need a resistor to 5v circ 10k.. MCLRE = OFF means tied internally

datasheet said:
bit 5 MCLRE: GP3/MCLR Pin Function Select bit(5)
1 = GP3/MCLR pin function is MCLR
0 = GP3/MCLR pin function is digital I/O, MCLR internally tied to VDD
 

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