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From: captkidd@athena.mit.edu (Ivan Cavero Belaunde)
Newsgroups: comp.sys.mac.programmer
Subject: Re: TicksCount
Message-ID: <1991Jun11.185747.9300@athena.mit.edu>
Date: 11 Jun 91 18:57:47 GMT
References: <5721@hemuli.tik.vtt.fi> <1991Jun11.092513.14329@cs.uri.edu>
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Organization: Massachusetts Institute of Technology
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In article <1991Jun11.092513.14329@cs.uri.edu> reynhout@cs.uri.edu (Andrew Reynhout) writes:
>In article <5721@hemuli.tik.vtt.fi> aku@tik.vtt.fi (Arto Kujala) writes:
>>Is there a way to get more accurate time than function TickCount
>>gives?
>>
>>1/100 sec precision would be appropriate.
>   Unfortunately, you'd need discrete hardware to do this.  The Mac gets its
>clock signals from the 60Hz AC input.  Of course, it would be very *simple*
>hardware...perhaps there is something out there.

Actually, the Mac gets its clock signals from crystals (I shudder to think
of a Mac getting its working frequencies from Boston Edison ;-), which
generate interrupts at specified intervals via counters in the VIAs. The
6.0.? (I think it's 6.0.3, but I'm not sure) Time Manager allows you to
install Time Manager tasks with a period of < 1 millisecond (it's
somewhere in the 20-40 microsecond range, I think). You can use that to
get your timing. In fact, the original Time Manager allows periods of
1 millisecond and greater, and should be good enough for your application.

-Ivan Cavero Belaunde
Digital Video Applications (DiVA) Corp.
Internet: captkidd@ATHENA.MIT.EDU
Disclaimer: opinions, assholes, you know...