Newsgroups: comp.sys.atari.st
Path: utzoo!utgpu!jarvis.csri.toronto.edu!godzilla.eecg.toronto.edu!lansd
From: lansd@eecg.toronto.edu (Robert Lansdale)
Subject: ACSI Info Wanted
Message-ID: <88Dec12.105127est.3285@godzilla.eecg.toronto.edu>
Organization: EECG, University of Toronto
Distribution: na
Date: Mon, 12 Dec 88 06:20:28 EST



     I  have been looking into building an ACSI to SCSI converter 
board  for my ST (I want more functionality than the ones on  the 
market at present),  but have come up against several obstacles - 
lack of complete documentation on the ACSI bus being the worst.

     If  anyone has toiled in this territory  before,  maybe  you 
could answer some of the following questions:

     1)  The only documentation I have on the ACSI bus is an  old 
application  note from Atari (September 1985),  but it is  rather 
incomplete. Is there a more complete, up-to-date document?

     2) Has anyone built an ACSI peripheral?  The interface seems 
simple  to build,  but some of the hold times (20ns for Initiator 
to Target Command phase, 50ns from Target to Initiator in Data-In 
phase) seem too short, or hard to generate without a delay line.

     3) What is the role of signal A1?  My document shows it only 
being asserted for Byte 0 of the Command phase.

     4)  What  is the Read/_Write signal doing  during  the  data 
phase?  My document does not show how it is asserted,  but I hope 
it reflects the direction of the transfer.

     5) Does anyone have an example ACSI driver for the ST?

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