So, for the rest of the day, I think I'm going to spend more time on my Seebeck clock project. I've gotten the PWM working using the ATmega8515, the chip that came with my development board. But I really want to be using the ATmega168 which has different timers and what-not. So I think I'm going to spend today porting the code to the ATmega168.
I have the chip working on a high precision 32.768kHz crystal. The PWMs are 8 bit, meaning they can produce a voltage between GND and VCC in 256 steps. The meters only take .1vDC to swing full scale (1mA with a 100ohm coil) so the plan is to use a voltage divider to scale it so that 0 to 240 will do full scale on the meter, meaning that I need the clock to tick 4 times a second (240 ticks / 60 seconds = 4 ticks per second). 4 ticks a second means a tick ever 8192 clock cycles, or conveniently every 32 roll-overs of the PWM counter which will conveniently trigger an interrupt if configured to do so.
This is the next step: configuring the timer roll-over interrupt to "tick" my clock for me. Hopefully, I'll be able to get all of this done today.