[Coco] CoCo/PC hybrid....

[Frank Swygert]

Looks like you're basically saying it would be easier to emulate the 
ports through a micro controller connected to a PC USB port like Steve 
did. I was thinking at first that the parallel port could be programmed 
to do basically the same without extra hardware, but then I looked at 
the CoCo and parallel pinouts and discovered that the addressing bits 
would be a problem -- they would take some hardware to decode. For that 
reason the USB port probably is the best solution. The data lines can be 
expanded cheaply though -- 
http://www.doc.ic.ac.uk/~ih/doc/par/pportexp/pportexp.asc The following 
document deals with the original, simple printer port, not current 
EPP/ECP bi-directional ports: 
http://et.nmsu.edu/~etti/fall96/computer/printer/printer.html Maybe 
access to the parallel port for inexpensive I/O would be a good feature 
for a CC4? I do understand that devices that once used the parallel 
port, like some external tape and disk drives, have been superseded by 
USB technology. As I said earlier, I was just thinking of maximum use of 
existing hardware. Even most brand new motherboards still have a 
parallel port, all but the most compact anyway. It can be software 
programmed just like PIA in the original CoCo. ---------- Date: Thu, 17 
Sep 2009 21:53:50 +1000 From: Mark McDougall <msmcdoug at iinet.net.au> 
Frank Swygert wrote: > That's pretty slick, but I think what I'm asking 
for would be cheaper to > make. You really just need a way to decode the 
address bits. Plus it > doesn't really need to read a cartridge, it 
could just act like the port > with a wire wrap header for 
experimenters. My idea is really to do it as > cheap as possible -- 
costs is the main reason the CC in an FPGA on a new > board hasn't gone 
over well.


You can buy USB-enabled micros for $2 in bulk. Or something like the FTDI 
chips which let you bit-bash over USB...

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)