Does anyone have the pinout (or a datasheet) for the SED9421 chip (18 pin
DIL package). I think it's some kind of floppy disk data seperator/PLL.
A web search has found nothing of obvious use...
If you want to send me anything other than plain text (like an image, or
a pdf), please don't send it here. Please send it to tony_duell at yahoo.co.uk
-tony
Brad,
Where are you located?
Lyle
--
Lyle Bickley
Bickley Consulting West Inc.
Mountain View, CA 94040
\"Black holes are where God is dividing by zero\"
--------- Original Message --------
From: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
To: cctalk at classiccmp.org <cctalk at classiccmp.org>
Subject: Cleaning out some old PC stuff
Date: 25/11/05 15:29
> This is 286 era things. I have manuals and hardware.
> Please no disparaging comments. No obligation or guilt
> will be meted out to anyone here.
>
> Main computer Compaq DeskPro 286.
>
> Following manuals available in short wide 3-ring binders
> 2 copies of MS-DOS Version 30 Reference Guide
> 2 copies of MS-DOS Version 3.3 Reference Guide
> BASIC Version 3
> Compaq Deskpro 286 Operations Guide
> Compaq Deskpro 286 Maintenance and Service guide
> 80286 Based Products - Volume I
> 80286 Based Products - Volume II
> MS-DOS Version 4 Reference guide (with 5 1/4" disks)
>
> AllChargeCard with manual
> AboveBoard PS/AT with manual
> AST Rampage 286 with manual
>
> Also Alps P2100 printer (Loud fast dot matrix) with muffler.
>
> All will hit local recycle place in two weeks if not spoken for.
>
> Bradley Slavik
>
>
________________________________________________
Message sent using UebiMiau 2.7.8
I discovered that in my recent modifications to the filename selection
code in ImageDisk, I introduced a bug which can cause it to close one
too many windows when you are entering a filename and supplying
the extension (if you don't supply an extension, ImageDisk will supply
the default ".IMD" and all is well) - The symptom is that you appear to
be back at the DOS screen, however the program is still active so you
keyboard does not appear to be working.
I have corrected this and updated IMD108.ZIP on my site (which now
shows 1.08a when run).
Regards,
Dave
--
dave04a (at) Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com Collector of vintage computing equipment:
http://www.parse.com/~ddunfield/museum/index.html
This is 286 era things. I have manuals and hardware.
Please no disparaging comments. No obligation or guilt
will be meted out to anyone here.
Main computer Compaq DeskPro 286.
Following manuals available in short wide 3-ring binders
2 copies of MS-DOS Version 30 Reference Guide
2 copies of MS-DOS Version 3.3 Reference Guide
BASIC Version 3
Compaq Deskpro 286 Operations Guide
Compaq Deskpro 286 Maintenance and Service guide
80286 Based Products - Volume I
80286 Based Products - Volume II
MS-DOS Version 4 Reference guide (with 5 1/4" disks)
AllChargeCard with manual
AboveBoard PS/AT with manual
AST Rampage 286 with manual
Also Alps P2100 printer (Loud fast dot matrix) with muffler.
All will hit local recycle place in two weeks if not spoken for.
Bradley Slavik
>
>Subject: Re: Pinout for SED9421
> From: shoppa_classiccmp at trailing-edge.com (Tim Shoppa)
> Date: Fri, 25 Nov 2005 16:56:16 -0500
> To: cctalk at classiccmp.org
>
>"Peter C. Wallace" <pcw at mesanet.com> wrote:
>
>> On Fri, 25 Nov 2005, woodelf wrote:
>>
>> > Allison wrote:
>> >
>> >> Either that a Dflop(74LS74), hex D-latch(74LS174) and 32x4 prom(74LS288).
>> >>
>> >>
>> > Just for the heck of it, got a schematic and a prom listing?
>> > Did anybody ever use a serial chip and a data separater
>> > rather than a floppy disk controler?
>>
>> Heathkit did with their H89 hard sectored floppy controller....
>>
>> >
>>
>> Peter Wallace
>>
>
>Also Ohio Scientific, I think that was with an async UART? (Don't
>know for sure, but I do know the best way to get the correct information
>is to post incorrect information!)
>
>Tim.
I think the part they used was an USART as in async, bisync, and HDLC/.x25
kinda thing.
Allison
>
>Subject: Re: Pinout for SED9421
> From: "Chuck Guzis" <cclist at sydex.com>
> Date: Fri, 25 Nov 2005 13:25:49 -0800
> To: cctalk at classiccmp.org
>
>On 11/25/2005 at 1:51 PM woodelf wrote:
>
>>Just for the heck of it, got a schematic and a prom listing?
>>Did anybody ever use a serial chip and a data separater
>>rather than a floppy disk controler?
>
>I've done it on lashups to read very oddball floppies. A 2651 in sync mode
>will go to something like 600KHz or 1MHz data rate.
>
The commonly used 2601 USRT was common, also the Z80 SIO in sync mode
or the NEC d7201(8274) as they were faster.
Allison
>
>Subject: Re: Pinout for SED9421
> From: woodelf <bfranchuk at jetnet.ab.ca>
> Date: Fri, 25 Nov 2005 13:51:27 -0700
> To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
>
>Allison wrote:
>
>>Either that a Dflop(74LS74), hex D-latch(74LS174) and 32x4 prom(74LS288).
>>
>>
>>
>Just for the heck of it, got a schematic and a prom listing?
Sure do. Send a scanner and a system that won't croak under the load.
It's in the net, someone about three months ago found it.
>Did anybody ever use a serial chip and a data separater
>rather than a floppy disk controler?
Yes, many. usually its a sync chip.
Allison
>Subject: Re: Pinout for SED9421
> From: Fred Cisin <cisin at xenosoft.com>
> Date: Fri, 25 Nov 2005 12:28:14 -0800 (PST)
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On Fri, 25 Nov 2005, Allison wrote:
>> >>The all time worst was the 1771 internal data sep. Tandy initally did
>> >that to save parts. Really bad.
>
>The 1771 may have CLAIMED to have an internal data separator; performance
>did not bear that out.
;) I'm not going to argue that! ;)
>You were much too gentle. Next time, we'll loan you a bigger bat.
Hey North actually called me obnoxious once. ;)
>the Micropolis lead screw was SLOW. But noticably more reliable than
>either the Shugart spiral, or the split bands.
Shugart whas prolific but not very good.
Allison
>Subject: Re: Pinout for SED9421
> From: "Chuck Guzis" <cclist at sydex.com>
> Date: Thu, 24 Nov 2005 14:19:32 -0800
> To: cctalk at classiccmp.org
>Has anyone noticed a significant performance difference between the PLL
>type data separators (e.g. the WD1691/2143 combo) and the plain-Jane WD9216
>digital ones? I suspect that the PLL type is more tolerant of drive speed
>variations, but that hardly matters all that much with modern drives. I
>don't recall finding a disk that failed to read on a generic 9216-equipped
>FDC but read fine on the old IBM PC floppy board.
>
>Cheers,
>Chuck
I've used he 9216 and 9229 and the NEC apnote digital data seperator
(prom state machine synthetic PLL) as well as a custom NEC ASIC (with
the prom data sep inside) and they all do very well. Testing against a
well developed PLL (not the WD animal) showed a small difference after a
4 days of continious read and writes (number of fails less than 3).
You have to do a very large number of reads without external influences to
see the difference. Power blips and the like were a pain. A small
difference was seen in the order of one of one failure per 250,000 reads
vs 1 in maybe 400-500,000 reads. You need a lot more testing than we did
then to get near 1:10^8 stats with any validity.
FYI:the average PLL is a bear to build and debug, they required clean
power and good board layout with ample groundplanes. The digital ones are
very good, simple to layout and shift rates with only a mux.
Allison
With my thanks to Don North for his permission, as well as his excellent page layout work, I have established a mirror of his site containing PROM images and source code for numerous DEC'ish boot PROMs, as used on the M9312 boards.
The link is -- http://www.bluefeathertech.com/technoid/promfiles.html
If you have trouble accessing the page (folks outside the U.S., notably those in the Pacific Rim countries, may run afoul of our firewall's filters), please drop me a note. If your E-mail bounces, put in a brief 'Page' for me here in the group, and I'll see what I can do.
Keep the peace(es).
-=-=-=-=-=-=-=-=-=-=-=-
Bruce Lane, Owner & Head Hardware Heavy,
Blue Feather Technologies -- http://www.bluefeathertech.com
kyrrin (at) bluefeathertech do/t c=o=m
"If Salvador Dali had owned a computer, would it have been equipped with surreal ports?"
