Path: utzoo!attcan!uunet!husc6!cmcl2!nrl-cmf!ames!oliveb!sun!pepper!cmcmanis
From: cmcmanis%pepper@Sun.COM (Chuck McManis)
Newsgroups: comp.sys.amiga.tech
Subject: Re: 5.25" drive question
Message-ID: <63738@sun.uucp>
Date: 10 Aug 88 18:42:28 GMT
References: <13132@agate.BERKELEY.EDU>
Sender: news@sun.uucp
Reply-To: cmcmanis@sun.UUCP (Chuck McManis)
Organization: Sun Microsystems, Mountain View
Lines: 22

[I nominate this one for the intro posting. :-)]

In article <13132@agate.BERKELEY.EDU> johnf@sag4.ssl.berkeley.edu () writes:
>I just can't seem to get the computer to mount the drive properly.  Any takers?
>john flanagan

When connecting a 5.25" disk drive to your Amiga you need to take into 
account the "Drive ID." This is the signal that the drive sends back
to the Amiga to tell the Amiga if it is an 80 track or 40 track drive.
In the Amiga schematics this is implemented as a flip-flop for the 5.25"
drive that returns 1010101010 as opposed to the 3.5" drives which return
11111111. When you leave this circuit out you get the 1111111 pattern and
so your Amiga thinks it is a 3.5" drive with 80 tracks. Of course the 
A1000 schematics package from CATS includes the schematic for the little
board they put on the A1020 drive, and that is the best place to get the  
information from. [You know the litany $20 to CATS, 1200 Wilson Dr, West
Chester, PA, 19380] 


--Chuck McManis
uucp: {anywhere}!sun!cmcmanis   BIX: cmcmanis  ARPAnet: cmcmanis@sun.com
These opinions are my own and no one elses, but you knew that didn't you.