4 Mar
2002
4 Mar
'02
9:08 a.m.
At 07:58 PM 3/4/02 +0000, Tony wrote:
I happen to have the 'Intellec Series II Microcomputer Development System
Double-Density Diskette Subsystem Schematic Drawings' here. (Phew, what a
title). I am not sure if this is the same unit that you have, but it
might provide some information. Unfortunately, I don't have any
information on the drives themselves -- there are no schematics or link
settings given. I do have info on the 2 multibus cards (controller), the
PSU, and the cabling.
I have that manual for both the MDS 720 drive (two drives laying
horizontally and using a double density controller) and for the older MS
2DS system (two drives mounted vertically and using the single density
controller) and NEITHER of them says one word about the drives! It's
amazing to me that intel would go to the level of detail that they do but
completely ignore the drives!
J1 P1
(cable) (drive)
Odd # Odd # Ground
2 46 Read Data
4 2 Not used (or even connected?) >> Not connected
6 42 Track 0
8 20 Index
10 16 Track <43 (is this really track > 43 ???) >>My
docs say "< 43" also.
Shugart says that pin 16 is an "alternate I/O" connector and it can be
used for whatever the manufacturer decides. I've checked and it does
connect back to the drive controller. So it's something else that I have to
investigate.
It's shown as track<43 on my schemaitc By the time it gets back the to
the 'FDC Interface', it's become 'Track>43 01/' (or
'Track>43 23/' for
the second drive cabinet). It's an output from the controller to the
drive and seems to be the standard reduce write current signal.
That's what I thought but I haven't had time to trace it all the way back
to the controller yet.
12 36 Step
14 34 Direction
16 40 Write Gate >> intel calls it "write safe"!
18 38 Write Data
20 26,28 Select 0 ) Either cable pin can be jumpered to
22 26,28 Select 1 ) both drive pins by the S0/S1 jumper >>
Correct.
24 4 Not used (or connected?) >> Not connected.
26 6 Not used (or connected?) >> Not connected.
28 22 Ready 0 ) Either cable pin can be jumpered to
30 22 Ready 1 ) drive pin 22 by the R0/R1 jumper
> Right. Drive pin 22 (Ready) can be jumpered to
either ready line of the
cable (pin 28 or 30)
32 10 Not used (or connected?) >> Not connected.
34 12 Not used (or connected?) >> Not connected.
36 44 Write Protect
38 48 Read Data (Separated) >> Not connected at P8.
40 14 Not used (or connected?) >> Not connected.
42 50 Read Clock (Separated) >> Not connected at P8.
44 18 Not used (or connected?) >> Not connected.
46 24 Not used (or connected?) >> Not connected.
48 30 Not used (or connected?) >> Not connected.
50 32 Not used (or connected?) >> Not connected.
There are no components other than connetors on the PCB in the manual.
Correct.
I don't think you need to worry about that. The controller seems to use a
1-of-n active low drive select scheme (2 DS lines per drive cabinet
cable), so you can just link each wire to a particular drive's active DS
line.
That's what I thought but I suspect there may be more to these. Shugart
had some odd options available like "seek without selecting a drive" and
"seek without loading the head" and this may be using one of those and that
may explain why they did it this way.
Joe