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