Hi,
Looking at Amtel's app note 2505, talking about running timer 2 in async mode as I am with a 32768Hz crystal, it says:
Note: The external clock frequency should be in the interval [0 Hz .. 256 kHz] and maximum CK/4.
Now is 'CK' the prescaled or non-prescaled CPU clock?
The reason I ask is that the technique I'm using for low-power timed delays is to drop the CPU speed to minimum (31250Hz, given use of the 8MHz RC clock and a prescaling of 256) while looping in _delay_loop_2().
If that CK is the CPU clock speed after prescaling then I'll need to run the CPU 8x faster, which is a pity, and I may want to find another technique.
Rgds
Damon