Dealing with infinite loop in an Interrupt Service Routine !!

[ROCKET SCIENTIST]

Hi guys,

Facing problems with ISR. I don't know to stop an infinite loop in an interrupt service routine. I have set 2 ext. interrupts. Now int_0 service routine has an infinite loop inside of it that just makes a pulse train.. But I want this while(1) infinite loop to stop whenever the other ext. interrupt, int_1 fires thus the execution process goes out of int_0 routine and into int_1 routine. Well, in practice, I've found that even when int_1 fires and the MCU starts to execute codes inside of int_1 routine, still then that infinite loop in int_0 routine is working!! 8-O It didn't stop. Now do u guys have any idea for how to get rid of it??

Now, I also tried this. In int_0 ISR I put a flag, PORTB=0; and instead of using while(1) I used, while(PORTB==0) and then in int_1 ISR I've changed flag into PORTB=1; Thought this might work, but no, it didn't. Hope you guys have some idea for this problem. Thanks in advance.

Here's the little code I've written:

//processor: Atmel AVR Atmega8

#define F_CPU 8000000UL

#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>

ISR(INT1_vect) {  //fires at rising edge
GICR=0; MCUCR=0; MCUCR |= (1<<ISC01); GICR |= (1<<INT0); 
//for the next int. set int0 at falling edge
PORTB=0; //flag for infinite loop
while(PORTB==0) {PORTC=1; PORTC=0;}
}

ISR(INT0_vect) {  //fires at falling edge 
GICR=0; MCUCR=0; MCUCR |= (1<<ISC10)|(1<<ISC11); GICR |= (1<<INT1); 
//for the next int. set int1 at rising edge
PORTB=1; //changing flag, trying to stop infinite loop
}


int main (void) {

DDRC |= 1; DDRB |= 1;
MCUCR=0; MCUCR |= (1<<ISC10)|(1<<ISC11); GICR=0; GICR |= (1<<INT1); sei();
//default int. setting: int_1 at rising edge

while(1) {/*doing nothing*/}

return 0; }

Regards,
Ro_S.

 

[paulfjujo]

hello,


It's not allowed to uses infinit loop inside a interupt treatment !

because you never exit from the ISR(INT1_vect) to be able to treat other interrupt..
It can be done only on evolued controller wich include PRIORITY level treatment...
I don't know AVR µP
do you have High and low priority like on Microchip 18F ?

maybe you can use PWM instead of PORTC=1 PORTC=0

 

[ROCKET SCIENTIST]

Thanks for the comment. INT0 has the higher priority than INT1. Ok, I think using infinite loop was not a good idea, but can I use a normal variable controlled loop in ISR?