Messages in this thread | | | Date | Thu, 8 Jul 1999 10:46:46 +0200 (MEST) | Subject | Re: Can't sleep less than 20 ms | From | Bernd Paysan <> |
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> Bernd Paysan wrote: > > UTIME has the problem of a slipping clock. > > I recall on the x86 there's a way to avoid the slipping using just the > timer chip, but I don't recall how off hand. Something about using > another of the timer counters as a reference.
There are two possibilities: use the TSC on Pentium and above, and use the RTC on lower end machines (just set up a RTC interrupt xxx times per second (e.g. 128), and capture the timer to get a known offset).
It would have been much better if there was a free running timer with a compare register (shoot when timer=reg), but we have to live with 20+ years old timers in a brain-damaged design now.
-- Bernd Paysan "If you want it done right, you have to do it yourself" http://www.jwdt.com/~paysan/
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