21 Nov
1999
21 Nov
'99
10:38 a.m.
I never gave this much thought because I have a compaticard, though I have
never used it. I've taken it out of the box, though, hence the manual,
floppy, and board are all in different (and unknown) places.
There's no doubt that the 765, which is the controller on which essentially
all PC FD controllers is definitely SD capable, since it's also used in one
of my S-100 systems where it does SD every day.
Surely there's some way to fool the FDC, perhaps by talking to it directly
to accomplish a few simple operaitons, which will enable you to read/write
SD 8" diskettes. I say this because the data rate for SD 8" is the same as
for DD 5-1/4, so the clock must be there. The rest has got to be software
once you've got the cable made.
Dick
-----Original Message-----
From: Don Maslin <donm(a)cts.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Sunday, November 21, 1999 4:44 PM
Subject: Re: Panasonic 8" Floppy Drive
On Sun, 21 Nov 1999, Olminkhof wrote:
> I've found a box with 2 x 8" floppy drives. . . . external to some
unknown
> computer.
>
> The box is a Panasonic JB3038P and inside are 2 X JA751 drives.
> The drive connectors and the cable coming out of the box are all 50 pin,
> exactly like an internal SCSI cable. Unfortunately it isn't recognised
by
a
> SCSI controller, at least not without fiddling
with parity and stuff like
> that.
>
> Does anyone know what this might have been for?
>
> SCSI 8" floppy drives would have been great cos I don't think I'm ever
going
to find a
compaticard !
Hans
You may not even need a CompatiCard, depending upon the disks that you
intend to read. You 'wire weave' a cable between a 50-pin SA800
connector and the usual 34-pin FDC connector using the information
below:
********************************************************************
The following table is extracted from the CompatiCard manual:
Card 34 37 50 8 Inch Drive
Signal Name Pin Pin Direction Pin Signal Name
========================================================================
Programmable 2 3 ---> 2 Low Current
Index 8 6 <--- 20 Index
Drive Select 1/3 12 8 ---> 28 Drive Select 2
Motor Enable 1/3 16 10 ---> 18 Head Load
Step Direction 18 11 ---> 34 Direction Select
Step Pulse 20 12 ---> 36 Step
Write Data 22 13 ---> 38 Write Data
Write Enable 24 14 ---> 40 Write Gate
Track 0 26 15 <--- 42 Track 0
Write Protect 28 16 <--- 44 Write Protect
Read Data 30 17 <--- 46 Read Data
Select Head 1 32 18 ---> 14 Side Select
Connect odd number pins of 34 pin connector to odds of 50 pin connector
Connect pins 21/37 of the DB-37 to all the odd pins on 50 pin connector
************************************************************************
If the disks you intend to read are double density a HD (1.2mb/1.44mb)
capable FDC should work fine. If they are SD, you may be in some
difficulty. However, there are 8-bit HD capable FDCs with onboard BIOS
that are capable of handling that also.
- don