Thu Oct 18 11:03:49 CEST 2018

Bit sync

So do it using the principles above:
- factor out the start/stop
- start it at 1/2 bit

This should really be done on paper... But, if it can be done on
paper, it can also be done as letrec.

edge' <- edge i
negedge <- e & ~i

bit_enable <- set_reset negedge count_carry

Why is this so difficult to express?  Maybe it is essential to put it
on paper first.