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| From: Crown (all posts)
Date: 1998-07-06
Subject: Re: Turbo emulating
|
Hi,
>That's nice, but there is a bit problem with this: 1541 cannot put
>data on lines right after ATN is flipped... It takes a bit time, and
>the stable sign-stand on the lines also takes a bit time... And this
>time is what I want to know...
According to a book I have here on repairing 1541 drives, there is four technology is used in the 1541, TTL, TTL-S, TTL-LS and NMOS.
They also gave the times for tipycal signal change.
TTL 10 ns, TTL-L 33 ns, TTL-S 3 ns, TTL-LS 9,5ns. These are pretty small values, so I think you don't need to bother with this.
For the sync you can write a simple loop which polls the line waiting for the sync acknowledge, and when this arrives, for safety reason you could wait 0.5 usec and sample it again, to check if its stabilized or not, but I think you will always get that its stable, if not, the worst what can happen that you will offseted by around 1 usec, but thats not a problem, as you have at least 6 usec safe window to read the lines....
Tibor Biczo / Crown of GOTU
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