[Coco] RS232 Schematics, was DriveWire survey

[CoCoList for Color Computer Enthusiasts]

>
> I agree, lots of opportunities, but I want to remain realistic. Right
now, I'd like to get something connected to the Coco Expansion port and
make sure I can read and write bytes to it.  Once that is in place, I'll
move to the next step.  Right now, Pi has issues, as it is master SPI mode
only (meaning it must be allowed to start the transfer, not receive it).
 That throws a wrench into some of the plans, but no worries at present.
>

Cool.  If I can do anything to help just ask.

> A 6551 interface holds a lot of value, IMHO, though, as almost all of the
6XXX environments used it for UART duties.  Making this working and putting
it on a 28 pin header would mean people could pop out their 6551 ACIA of
their RS232 Pak, pop this in, and try things out with limited help.
>

That does sound good for compatibility. Would it mean throughput limited to
traditional 6551 speeds?  Thats the only potential drawback I could see.
Even the 1.x MHz coco craves data at rates in the (low) mbps range :)