TRS-80 Model II

From: Jeff Kaneko <Jeff.Kaneko_at_ifrsys.com>
Date: Wed Feb 25 08:30:49 1998

You know, I have a WD-1000-XX controller that supposedly can talk to
these drives. It also can talk to 5.25" drives.

These controllers are SASI on the 'other' end (I think).

Hmmm. I don't see many SA-1000's being offered for sale . ..

Jeff

> > Those are 8.4MB drives. Not SCSI, not even ST-506. Those are 8"
> > Shugart mechanisms in there, 4 heads by 256 cylinders. I forget
> > how termination worked in those units (haven't seen one in action
> > in at least 12 years). And yes, the write protect switch and the
>
> Probably an SA1000 type interface. It's similar-ish to an ST506 interface
> in that there's a control cable that goes to all the drives and a
> separate data cable from each drive to the controller.
>
> The control cable has 50 wires, and is sort-of 8" floppy drive like. In
> fact you can have a mixture of 8" SA800 floppy drives and SA1000
> winchesters on the same control cable (up to 4 drives total). The data
> cables were only used on the hard drives, of course.
>
> You terminate the control cable at the last drive (furthest from the
> controller). The data rate is 4.34Mbps.
>
> Here's a pinout od the control cable. All odd numbers are ground...
>
> 2 Reduce Write Current*
> 4 Head Sel 2*
> 8 Seek Complete*
> 14 Head Sel 0*
> 16 Sector Pulse*
> 18 Head Sel 1*
> 20 Index Pulse*
> 22 Ready*
> 26 DS1*
> 28 DS2*
> 30 DS3*
> 32 DS4*
> 34 Step direction (low = in)
> 36 Step Pulse*
> 40 Write Gate*
> 42 Track 00*
> 44 Write Fault
>
> Rest not used.
>
> The data cable has the same pinout as an ST506 data cable, apart from an
> extra clock from the controller to the drive on pins 9 (+ve) and 10
> (-ve).
>
> > Ward Griffiths
>
> -tony
>
>
Received on Wed Feb 25 1998 - 08:30:49 GMT