Pinout for SED9421
Dwight K. Elvey
dwight.elvey at amd.com
Mon Nov 28 13:27:53 CST 2005
>From: "Allison" <ajp166 at bellatlantic.net>
>>Subject: Re: Pinout for SED9421
>> From: "Dwight K. Elvey" <dwight.elvey at amd.com>
>> Date: Mon, 28 Nov 2005 10:46:28 -0800 (PST)
>> To: cctalk at classiccmp.org
>>>From: "Allison" <ajp166 at bellatlantic.net>
>>>> From: woodelf <bfranchuk at jetnet.ab.ca>
>>>>Did anybody ever use a serial chip and a data separater
>>>>rather than a floppy disk controler?
>>>Yes, many. usually its a sync chip.
>> Besides the HeathKit hard sectored controller board,
>>used on both the H8 and the H89, Polymorphics also
>>used a serial chip to do data. In both of these
>>cases, as you state, they used synchronous serial
>>chips and not async.
>Err, Yes that's what I did say. Sync chips were the norm
I'm not contridicting, just pointing out some cases
to support. As I recall, the N* controller also used
the synchronous serial chip. I don't know of a case
that used a async part. All of these were used on
hard sectored disk.
I don't know of any soft sectored that used serial
chips. I suspect that it is because these depended
on using illegal data clocking sequences in order
to mark sectors. This would require more external
>for brewed designs there were not OSI or done with TTL.
>Often they were used because WD could not supply or was
>not viewed as the desireable item due to lack of second
>source (at least early on). Some did it to have a
More information about the cctalk