AVR-Chat

I must be missing something..

I have timer T0 running as a PWM generator with the AS0 bit in ASSR 
set, and external 32kHz crystal.
Now I want to put the system to sleep, and have T0 wake me up once a 
second for time keeping.
The problem is that once I go to sleep, the T0 int only happens ONCE!
It gets better though.. If I hang a breakpoint in the T0 ISR, and F10 
through it, I get through the loop just fine, and I keep getting to 
the T0 int. It's only when I let the code run without F10ing it, that 
it fails to hit the T0OV isr.

Without the sleep, the T0 int fires once a second, and everything 
acts like it should.

As I read the data sheet, T0 is supposed to be enabled to the 
external crystal in ESB mode, so what's not right here?



At this point, I've decided to go to sleep:
So, I configure T0 for normal operation instead of PWM

	;Set timer 0 for once a second wakeups

	ldi		TEMP,128	;
	OUT		TCNT0,TEMP	;LOAD THE COUNT UP COUNTER

	ldi		TEMP,$06	;
	out		TCCR0,TEMP	;

I wait to make sure everything "took"

T0_Sleep_Update:

	in	TEMP,ASSR		;0000XXXX	Reserved
	andi	TEMP,$07		;XXXXX111	T0 async mode enable
					;00000---	Busy flags, 1 if register updating
	brne	T0_Sleep_Update	;

I clear off the T0 int flags:

	in	TEMP,TIFR		;
	andi	TEMP,$03		;Mask out non T0 bits
	out	TIFR,TEMP		;Turn off flags by writing 1's to them

I turn off the T2 overflow int that was doing my timekeeping while awake.
I turn on the T0 overflow int.

	in	TEMP,TIMSK	;
	andi	TEMP,$BF	;10111111 T2 overflow off
	ori	TEMP,$01	;00000001 T0 overflow on
	out	TIMSK,TEMP	;

I set the sleep mode

Snooz_Loop:

	;Set up the sleep mode
	in		TEMP,MCUCR			;
	ori		TEMP,$3C			; Extended Standby mode
	out		MCUCR,TEMP			;

Then I sleep:
	sleep						;

	in		TEMP,MCUCR			;
	andi		TEMP,$DF			; disable sleep
	out		MCUCR,TEMP			;


	;Wake up here on pressed button ints, or T0 overflow

	I do some checks here after I wake up and the T0 ISR exits,

	breq	Snooz_Loop			;If nothing going on, resume sleeping

If I was to get that far, then i would restore everything on the way 
back to normal operation.