Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!wuarchive!waikato.ac.nz!comp.vuw.ac.nz!actrix!Roger.Sheppard
From: Roger.Sheppard@bbs.actrix.gen.nz
Newsgroups: comp.sys.atari.st
Subject: Re: 1.44mb drives
Message-ID: <1991Mar15.130107.11374@actrix.gen.nz>
Date: 15 Mar 91 13:01:07 GMT
References: <1991Feb28.085205.28239@phoenix.pub.uu.oz.au> <1991Mar06.123439.20676@actrix.gen.nz> <2886@krafla.rhi.hi.is>
Sender: Roger.Sheppard@actrix.gen.nz (Roger Sheppard)
Organization: Actrix Information Exchange, Wellington, New Zealand
Lines: 31
Comment-To: adamd@rhi.hi.is

Distribution:world 

In article <2886@krafla.rhi.hi.is> adamd@rhi.hi.is (Adam David) writes:
> In <1991Mar06.123439.20676@actrix.gen.nz> Roger.Sheppard@bbs.actrix.gen.nz writes:
> 
> The WD1772 controller has to be the more recent type for it to work properly.
> All recent ST's should have the right chip. The suffix on the older chip is -01
> and on the newer one is -02. I think the date-stamps are 1985 and 1987. The
> simplest way is to let the density sense line select the clock speed. The clock
> to the controller should be deglitched during the speed change. If you want to
> format DD disks to HD (doubtful practice) then a little more circuitry is
> required, probably involving the sound chip.
> It would be nice to change the step rate for the drives to suit the disk each
> time a disk is changed.
> 
> Does anyone know whether the WD1772 can handle 1024-byte sectors?
> If so then it should be possible to format 1848k onto a HD disk.
> --
> Adam David.
> adamd@rhi.hi.is

Yes it can, the Sector Length byte is 03 for 1024,
Note, I think the Germans use the 22 sector format to get this size,
but you will have problems booting with a 1024 sector, the TOS does not
suport that size,
But have seen some use od a Driver and a Mix of 512 and 1024 sector size.
From what I now, the -02 Part No. for the WD 1772 was for the Atari
none standard step rate, but I could be wrong.

Note , Atari does not use the WD1772-01 step rates of 2/3/5/6ms,
but use 2/3/6/12 , this I think is why the Part No. is WD1772-02
-- 
Roger W. Sheppard   85 Donovan Rd, Kapiti New Zealand...