Todo
====

Flasher
Supervisor
PWMIn
Servo
Link

Bandwidth
=========
https://docs.google.com/spreadsheet/ccc?key=0Alf_rWdmv9JidFBhNGc3M1VKR2ExOTBCTXhnN3JXdXc&usp=sharing

38400 baud gives 11 % utilisation at a 50 ms update rate.

PWM timing
==========
Signal goes from 1 ms to 2 ms.  Prefer an 8 bit value with a small
amount of margin for setting up the output compares.

So 1 ms should be ~256 count.  12 MHz / 1000 / 256 = ~47.  A prescaler
of 64 gives 187 count over 1 ms.  Sounds good.