Path: utzoo!utgpu!watmath!att!tut.cis.ohio-state.edu!rutgers!mit-eddie!uw-beaver!tektronix!sequent!mntgfx!dclemans
From: dclemans@mentor.com (Dave Clemans @ APD x1292)
Newsgroups: comp.sys.atari.st
Subject: Re: CMI Accelerator Board
Message-ID: <1989Aug7.174249.3330@mentor.com>
Date: 7 Aug 89 17:42:49 GMT
References: <12871@well.UUCP>
Organization: engr
Lines: 27

I can report a success story at installing the CMI accelator board.
This was done to an original style 520st system (board rev. E) using
the socket method (i.e., I didn't piggyback ontop of the 68000 chip).
You do need flywires, as the previous messages have stated; you need
the bus control & clock signals generated from the circuitry on the
board, and not the ones directly from the 16mhz 68000 chip.

One question... the red fly-wire, documentated as connected to R4
on the 520st, and un-connected on the Mega-st... what is its purpose?
At least for me, the board seems to work regardless of whether or not
the red wire is connected.  My copy of the st schematics (which admittedly
might not match the motherboard revision I have) shows R4 as being in
the midi data current loop circuitry.

A note on the manual... the way I read it it implies that you get 16mhz
operation by closing the jumper, and 8mhz by leaving it open.  However
on my system it's just the opposite; 8mhz when the jumper is closed,
16mhz when it's open.

A couple of final questions?

What are the recommended parts to use the fastrom sockets directly on the
board?

What is the definition of the "expansion" pins?

dgc