7i80 and 7i77

Sserial "DoIt not cleared" messages are most commonly caused by real time delays
(the cycle after a late cycle doesn't have enough time to complete)

The "tmax" values are parameters rather than pins

Another useful parameter is "servo-thread.tmax" which is the entire servo thread maximum time, and
the pin "motion.servo.last-period" which is the entire period

If you have a 3 GHz CPU, divide the timing numbers by 3000 for uSecs