Encoder improvements for THCAD

LinuxCNC master has a minor change in the encoder driver code to improve frequency
measurement resolution, This will improve the noise performance of the THCAD
somewhat so is worthwhile enabling. What changed was the timestamp frequency
that is used for encoder velocity/frequency calculations. This was set to nominally
1 MHz before the change. This default frequency has been increased to 2 MHz and
now has an option allowing a 10 MHz frequency to be selected. To select a 10 MHz
timestamp frequency, you set the hm2_card.0.encoder.hires-timestamp pin "true"

Thansk Peter. So users of master branch chould enable the 10 Mhz setting for best performance? I take it this specific to mesa hardware and the hostmod2 driver?

Sounds like this will be useful fo those cheaper plasma cutteres wher ethe arc voltage signal is quite noisy.

Yes, this is HostMot2 specific, and actually the difference will be most apparent
where the signal is cleanest.

What hardware and servo thread rate do you have?

Hmm I can't duplicate this with a 7I92 and a 1 ms servo thread (or 7i96 or 7I76E)