Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!udel!rochester!rit!ultb!clf3678
From: clf3678@ultb.UUCP (C.L. Freemesser)
Newsgroups: comp.sys.atari.st
Subject: Re: External 360k 5.25" floppy
Summary: How to build one
Message-ID: <1602@ultb.UUCP>
Date: 11 Nov 89 03:27:56 GMT
References: <1989Nov10.062019.19498@rpi.edu>
Reply-To: clf3678@ultb.UUCP (C.L. Freemesser)
Organization: Rochester Institute of Technology, Information Systems
Lines: 29

In article <1989Nov10.062019.19498@rpi.edu> vicc@unix.cie.rpi.edu () writes:
>I've got a 5.25" floppy w/cable to connect to the ST. How do I get the
>ST to use the drive? Is it a TOS porblem (I've got an oldish system
>but I don't know what version of TOS - certainly not 1.4) The drive
>spins when I access B: even though it asks for a disk in A: so
>something is going right.
>
There are a few things you have to do to get it to work:

1) Remove the resistor terminator pack
2) Track down a 150 Ohm resistor that's tied to the +5V line.  This
   resistor brings the voltage down to 2.5V when the drive is called.
   However, the Atari needs it to be 0V.  Replace it with a 1K Ohm 
   resistor.
3) Get a copy of the PCF554.PRG program.  You have to slow down 
   the access to drive B (the 5.25 inch drive) to 6ms.  It cannot
   reliably access the drive at 3ms.

You'll also have to use a program like DC Format 3.02 to format the
disks.  You cannot format them using the desktop.  Also, you will have
to mess with the different jumper blocks on the board to find the
correct configuration.


Chris Freemesser, Rochester Institute of Technology :BITNET:%clf3678@RITVAX
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