Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!SFAUSTIN.BITNET!Z4648252
From: Z4648252@SFAUSTIN.BITNET (Z4648252)
Newsgroups: comp.sys.atari.st
Subject: Hard drive sequencing
Message-ID: <890511.22134072.080648@SFA.CP6>
Date: 12 May 89 04:13:41 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 31

Allan Pratt writes:

"Yes, we could issue the "Test Unit Ready" command to the controller, and
if there's no response, then there's no controller.  If there is a
response, and it's negative, we can keep asking until it's positive.
However, there's still a timeout -- it may be that the controller is
getting power but the drive unit is not, so it'll NEVER be ready.  How
long do you propose we wait?"

    I can't vouch for non SH204's but I've seen power up handled perfectly
in times under eight seconds.  I'd think that ten to twelve would be the
max.  All the sequencers that I have built are set at ten and I've yet to
receive a complaint at that level.
    A newer design which I'm prototyping is not using direct delays at all.
It merely gives power to the ST when the SH204's LED stops flashing during
powerup.
    I wish I knew more about this stuff.  Shucks, TOS 1.4 wouldn't have to
be changed at all.  Plug the ST into the hard drive.  Don't allow power to
go to the dedicated ST plug until things are 'ready'.  I know this works,
primitive as it is.
    My new sequencer is all but finished.  I'm only trying to get costs
cheaper so that it would be better markettable.  Just install a delay
on the next batch of hard drives using the aforementioned dedicated ST
plug.
    Be sure to place a power switch up front for use of floppies that
require cold bootup and other bootup controls so that the drive doesn't
take control even though it isn't needed.  I'm thinking about auto-booting
games, etc.  Cold booting will sometimes cause the hard drive to kick in.
    Sigh, all sorts of suggestions, right?

Larry Rymal <Z4648252@SFAUSTIN.BITNET>