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Path: utzoo!mnetor!seismo!rochester!dibble
From: dibble@rochester.ARPA (Peter C. Dibble)
Newsgroups: comp.sys.m6809
Subject: Re: COCO 3 problems
Message-ID: <23404@rochester.ARPA>
Date: Tue, 23-Dec-86 15:11:05 EST
Article-I.D.: rocheste.23404
Posted: Tue Dec 23 15:11:05 1986
Date-Received: Tue, 23-Dec-86 22:44:04 EST
References: <1986Dec15.155154.14868@utcs.uucp>
Organization: U of Rochester, CS Dept., Rochester, NY
Lines: 30
Summary: Guess: Software doesn't run a precise clock.

In article <1986Dec15.155154.14868@utcs.uucp>, ac@utcs.uucp (Mark Acfield) writes:
> 
> Subject: COCO 3 clock speed
> ...
  paraphrased "I suspect that the CoCo3 has an inaccurate occilator."
> I decided to check this out using the TIMER function built into basic.
> The result of my experiment, which by this time came as no surprise, was
> COCO 3 counts of 60 seconds in about 58 seconds or real world time.
> ...
> My little timer program is listed below (as well as I can remember it):
> 10 TX=999
> 20 TIMER=0
> 30 '
> 40 T=INT(TIMER/60)
> 50 IF T<>TX THEN PRINT T:TX=T:SOUND 100,1
> 60 GOTO 30

What's the ' in the basic program.  Is the idea to see whether the
program beeps in 999 seconds?

I checked the accuracy of the CoCo 3's clock with the date t command in
OS-9.  It was losing less than half a second per minute.  Since you found
that several CoCo's were losing 2 sec per min in Basic and I got a different
figure under OS-9, I'd guess that the problem is in software.  Given that
the CoCo3 has a countdown timer, that sounds like a good guess.

See page 221 of the Tandy manual for the CoCo 3 where it says that TIMER
returns a number that is incremented ROUGHLY every 60th of a second.

Peter Dibble