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From: Crown (all posts)
Date: 1998-07-02
Subject: Re: Turbo emulating
Hi there,

>I there is an other problem for me: how to find out the running time
>of the 6501 side?
The clock of the 1541 runs at 1Mhz, so 1 cycle takes 1 usec.
It has a 6502 CPU, and the instruction cycle timings are available at various places... One source is for example the 64doc mentioned previously on this list...

>This is not the point, because a MC68030-50Mhz is much faster than a
>simple 1541, and there is a fine timing with included CIA-s, no need
>insturction timing.
Are you sure, that you can sample it on a usec resolution using timers???
You have to sample it on cycle base (either with the speed of the Plus4
or with the speed of the 1541), as slower sampling rates could cause errors, because of the varying syncronization phase diffs of the two equipment.
You have only 50 MC68030 cycle for processing one 1541 cycle,
that is not much...

Tibor Biczo / Crown of GOTU

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