[Coco] DriveWire survey

[CoCoList for Color Computer Enthusiasts]

On 5/11/2014 2:14 AM, CoCoList for Color Computer Enthusiasts wrote:
> Looks like the CD line can trigger an IRQ.  Is that what you were
> thinking  Buffer some bytes in a uC, trigger the Coco, and it asks for the
> data?
>> Or, are you suggesting a cartridge that will IRQ when there is data to
> receive?
>
> More the latter.  I think there is an issue with the interrupt that CD on
> the bitbanger can trigger that makes it not suitable, but I don't know the
> exact details.  Unfortunately I am not very well versed in the hardware.
Good, because I think that approach has limited runway.
>
>> Was there an official UART cart and is the schematic available anywhere?
>
> It doesn't have schematic but does have some info about the pins on the
> cartridge,dunno if that helps.  Somebody on the list might know where more
> info lives if its around anywhere.
No worries.  I got what I needed.

6551 register set (same as the CBM folks), FF68-ff6b address space...

Let me see if I can put together a replacement, as it would be fastest 
to develop...  The stock 6551 can do 115200 and will signal IRQs on each 
byte received.

I assume DW4 does not suport the RS232 cart right now?

Jim