Pinout for SED9421

[Allison]

>
>Subject: Pinout for SED9421
>   From: lee davison <leeedavison at yahoo.co.uk>
>   Date: Sat, 26 Nov 2005 00:43:13 +0000 (GMT)
>     To: cctalk <cctalk at classiccmp.org>
>
>>> 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
>
>6850 Async UART clocked at 125K bits/s, and a PIO for the control
>lines.
>
>Lee.

Sure it wasnt the 6852 SSDA?  UARTs generate start and stop bits and
even for a 128 byte sector that's 32 lost byte times as overhead.
You could use a UART though but, storage efficientcy is then degraded.

I went that path to do tape (FM encoded) so it's familiar.

All of the designs I'd seen used synchronous serial parts from the old
com2601/2651/2661 family and relatives under different names.


Allison