Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!uunet!mcsun!hp4nl!rulcvx!rooijen
From: rooijen@rulcvx.LeidenUniv.nl (A.J. van Rooijen)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: 14Mhz Comments
Message-ID: <994@rulcvx.LeidenUniv.nl>
Date: 11 Oct 90 08:30:38 GMT
References: <1164@tau.sm.luth.se> <1990Oct9.230639.9336@actrix.co.nz>
Distribution: comp
Organization: Leiden University, the Netherlands.
Lines: 24

In article <1990Oct9.230639.9336@actrix.co.nz> geoff@actrix.co.nz (Geoff McCaughan) writes:

>If anyone knows a way to get this thing running 100% I'd like to
>know about it.

To make the board work for 100% you must emulate the 7MHz 68000 behaviour of
your board for the processor socket. No matter how fast your board is. The
best thing to do is to generate the E-clock yourself instead of dividing
E-clock signals and take care of the VMA/VPA stuff. Furthermore you have 
to synchronize the DTACK* and the AS* with the original 7Mhz clock according 
to the M68000 specifications.
In practice this will mean waitstates. All this requires some more components
than a simple F logic FlipFlop. We have a prototype running for months now,
without a problem, no gurus or something like that. The speed increase is
around the 20-25%, however a program containing just DIV's and MULU's will
approach 100% (not a realistic situation).
I hope this will clear things up around the 14 Mhz hack, which is not so
simple afterall.

Erwin van Breemen

The Orega Programming Group Holland
Apothekersdijk 24
Leiden Holland