Hi John,

I think that is a great idea and will allow the full 1MHz rate of the THCad. But I think your logic is wrong so you are not getting quadrature.

To convert a 2-bit counter to A/B Quadrature I think the simplest way is with an Exclusive OR gate.

A = MSB
B = MSB ^ LSB

Code:
MSB LSB  A   B
---------------
 0   0   0   0
 0   1   0   1
 1   0   1   1
 1   1   1   0
 0   0   0   0
 0   1   0   1
 1   0   1   1
 1   1   1   0
 0   0   0   0
 0   1   0   1
 1   0   1   1
 1   1   1   0
HTH
Regards