watchdog reset

edited February 2017 in Questions & Answers
as i´m building a new machine now, i got following issue:

(cartesian system,rod driven,arduino due)

with high microstepping ( >3000 steps/mm) i get watchdog timeout . it even happens during homing.
when i reduce to half , everything is ok.
i also have to add stepper high delay which makes things worse.

any idea what to change?


  • Yes. It is possible to consume 100% with stepper interrupt causing the watchdog to never reset as temperature loops never run. So it might even be good. I even had the case that I could see the display slowly updating as cpu blocked so many time.

    With your reduction to 1500 steps/mm you freed enough time to run a bit on main thread.
  • is there a trick  to go with higher steps/mm?
  • Move slower or use a Arduino due whcih can handle higher speeds. Also make sure to have quad stepping enabled and a good switching frequency. On AVR 8000 is good and on due 80000Hz. YOu need earlier as you can go without double switching since each step will then take longer. 
  • edited February 2017
    I already use Due so i think my stepper drivers are too slow as i need stepper high delay and direction delay 2us .
    seems the built in optocouplers are too slow
  • Ok, with delay that slows down speeds. My numbers are for drivers without any delay. Optocoplers always slow down and also some cnc drivers are pretty slow, whcih was the original reason adding the delays.
  • Ok, so I´ll  have to find a compromise between Speed and precision.

    or/and Change the optocouplers as there are really fast ones available

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