Why not use one of the on-board timers?  That's what they are there for.

Andy









Chris Eddy <ceddy@NB.NET> on 03/20/2000 06:11:45 AM

Please respond to pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU>








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 cc:      (bcc: Andrew Kunz/TDI_NOTES)



 Subject: [ot] interrupt latency under DOS?








I have a turbo C program running under datalight RomDOS.  I have tricked
the clock into interrupting much faster than normal, and dividing down
to call the regular clock (a common trick in DOS).  Alas, I need to go
even faster.  Knowing that the 486/Pentium architecture has cache
running and pipelining and crap like that, I cannot rely solely on
setting a pin and resetting at the end of interrupt for a duration.
(The power of a PIC!) Does anyone have worst case figures on a Pentium
or 486's interrupt latency? Any tricks to confirm that the interrupt is
short enough?

Thanks
Chris Eddy