Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!brutus.cs.uiuc.edu!apple!olivea!tymix!tardis!jms
From: jms@tardis.Tymnet.COM (Joe Smith)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Need pinout on disk drive port
Summary: "motor-on data" is very important.
Message-ID: <1178@tardis.Tymnet.COM>
Date: 11 Aug 90 02:40:18 GMT
References: <1990Jul26.010258.20957@eplrx7.uucp> <13454@cbmvax.commodore.com>
Reply-To: jms@tardis.Tymnet.COM (Joe Smith)
Organization: BT Tymnet, San Jose, CA
Lines: 23

In article <13454@cbmvax.commodore.com> adam@cbmcats.UUCP (Adam Keith Levin) writes:
>From the "Amiga Hardware Reference Manual" by Commodore-Amiga,
>published by Addison-Wesley (ISBN 0-201-18157-6).
>
  EXTERNAL DISK INTERFACE CONNECTOR SPECIFICATION
  -----------------------------------------------
  8   MTRXD*   OC   Motor on data, clocked into drive's motor-on
                    flip-flop by the active transition of SELxB*.
                    Guaranteed setup time is 1.4 usec.
                    Guaranteed hold time is 1.4 usec.
>Adam Keith Levin  --  CATS     Commodore Applications and Technical Support

Adam, you left out the most important piece of information - the details
about the "motor-on data".  When AmigaDOS is reset, it sends a signal out
to DF1, DF2, and DF3 asking them to identify themselves.  It expects to
see a pattern of bits come back on pin 8 that say "I am an Amiga 3.5 inch
drive" or "I am an Amiga 5.25 inch drive".  Without this signal, the Amiga
will refuse to automatically recognize the drive.
-- 
Joe Smith (408)922-6220 | SMTP: jms@tardis.tymnet.com or jms@gemini.tymnet.com
BT Tymnet Tech Services | UUCP: ...!{ames,pyramid}!oliveb!tymix!tardis!jms
PO Box 49019, MS-C41    | BIX: smithjoe | 12 PDP-10s still running! "POPJ P,"
San Jose, CA 95161-9019 | humorous dislaimer: "My Amiga speaks for me."