Hi - I'm using timer2 on an ATMEGA168PV for an RTC. In normal, high power mode, I have the prescaler set to 8 so that I can interrupt at 1024x/second. (clock = 32768Hz, prescaler = 8, OCR2A = 32768/(8*1024) - 1)
However, when in low power mode, I'd like to interrupt a lot slower. With the prescaler set to 8 I believe the slowest I can interrupt at is 16Hz (OCR2A = 32768/(8*16) - 1 = 255). That is OK - but I'd be happier if I could interrupt at 1Hz.
Is there any way to switch my prescaler values without losing any clock cycles?