[Coco] CoCo "user" port?

[Leon Howell]

Phill Harvey-Smith wrote:

> I believe when I checked a few months ago the PIA lines that are used 
> for the CoCo Bitbanger, all appear on the Dragon Paralell port,

This gives me an idea for an interesting hardware project.

Are the other PIA lines used on the Dragon paralell port used for anything in 
the CoCo 3? If not, why not build an adapter that expands the port to a full 
paralell port, that can also bit-bang serial? If the address is the same, we 
could easily use dragon printer drivers.

How hard would it be to make the port bi-directional?

The Commodore 64 has exactly the same kind of serial/parallel port, and it is 
used for modems, serial printers, parralell printers, video digitizers, and 
voice recognition. It is called the "user" port. I don't know why.

Of course, I'm not sugesting we make the CoCo version commodore compatible, 
but when I get home I'm going to see if the end of my VICModem will fit in the 
space the RGB cable comes out of...

By the way (LOL) the C=64/128 has *hardware* serial capability on the same 
port, (remember the "forgotten chip" project?) but no Commodore program ever 
used it! DUH!?