Wake-up from sleep using INT pin

[WindWalker]

Hello,

I'm trying this with a PIC16F722. I wrote the code so the interrupt would happen at falling edge, I enabled pull-up resistors at PORTB, so I think interrupt should happen when shorting RB0 (INT) pin to Ground.

The PIC should do the following: light a LED for 5 seconds (RB7 as output), wait 1 second, go to sleep, wait for interrupt, light a LED for 5 seconds, ...

What happens: the LED is lit for 5s, MCU waits 1s, MCU goes to sleep (I can tell that because current drawn goes down to 20 uA @ 5 V) but doesn't wake up.

#define	XTAL_FREQ 16MHZ	/* MCU frequency in MHz */
#include <pic.h>
#include "delay.h"

__CONFIG(BOREN & MCLREN & PWRTEN & BORV25 & WDTDIS & INTIO & PLLEN & UNPROTECT);
__CONFIG(VCAPRA5);


void System_init(void){

	if (XTAL_FREQ == 16MHZ)
		OSCCON=0b00110000;
	else if (XTAL_FREQ == 8MHZ)
		OSCCON=0b00100000;
	else if (XTAL_FREQ == 4MHZ)
		OSCCON=0b00010000;
	else if (XTAL_FREQ == 2MHZ)
		OSCCON=0b00000000;

	[COLOR="Red"]ANSELB=0b11111110;[/COLOR]  //code correction
	TRISB =0b01111111;
	RBPU  =0;

	INTE=1;		//enable interrupt at INT pin - RB0
	INTF=0;
	PEIE=1;
	GIE=1;
	INTEDG=0;	//interrupt on falling edge


}

static void interrupt isr(void){
	if(INTF && INTE){
		INTF=0;
		INTE=1;

	}
}

void main(void){

	System_init();

	while(1){				//looping

		RB7=1;
		DelayMs(5000);
		RB7=0;
		DelayMs(1000);

		SLEEP();

	}
}

Thanks in advance,

 

[WindWalker]

I got it to work. Just needed to clear the ANSELB bit corresponding to RB0 pin, so I just added

ANSELB=0b11111110 (note that ANSELB=0b11111111 on Power-On Reset)

before TRISB=0b01111111 instruction

With the corresponding ANSELB bit set, digital buffer was disabled, so pin was configured as analog input, with its digital input function disabled.


Thank you,