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Article #4279Re: int 70h
From: Dave Parkinson
Date: Wed, 16 Jan 1991 10:30
Date: Wed, 16 Jan 1991 10:30
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1253 bytes
jfjr@mbunix.mitre.org (Freedman) writes: > I need to get a timer of about 1 millisecond granularity. > My first impulse was to check out int 70h. Since then I just depends what you're after..... The system tick interrupt (18.2 times a second) is derived from timer 0. this divides its input clock (1.19318MHz) by 65536 to provide the system tick interrupt. The internal divisor registers are readable, and thus it is possible to work out how far you are between system ticks. (It is some time since I used this feature and I seem to recall I had a problem in this area - using it as an absolute timer). Some years ago I used this technique to provide a delay routine that worked with a resolution of 1 ms. I don't know if you're after an accurate timer or an accurate delay...... davep@gapos.bt.co.uk
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!mcsun!ukc!axion!gapos!davep From: davep@gapos.bt.co.uk (Dave Parkinson) Newsgroups: comp.os.msdos.programmer Subject: Re: int 70h Message-ID: <davep.664021829@gapprd> Date: 16 Jan 91 10:30:29 GMT References: <127744@linus.mitre.org> Sender: usenet@gapos.bt.co.uk (Usenet login) Organization: British Telecom Applied Systems. Lines: 20