Gpio not turning high in led blink program

[Sreejith arikath]

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]

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]

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:

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]

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?.

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:

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.

 

[Nigel Goodwin]

Just tried simulating it, seems to work fine (with GP2 = 0; added) and GP2 toggles between 1 and 0.

 

[Ian Rogers]

#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

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

 

[Nigel Goodwin]

This is worded wrong MCLRE = ON means you need a resistor to 5v circ 10k.. MCLRE = OFF means tied internally

Well spotted, I just took it as correct because that's what the comment says. Assuming of course he's not got an external pull-up resistor on MCLR?.