[Coco] Chris Hawk's Rapsbery PiCo

[Christopher R. Hawks]

On Sat, 30 Mar 2013 18:27:19 -0500
Allen Huffman <alsplace at pobox.com> wrote:

> On Mar 30, 2013, at 2:02 PM, "Christopher R. Hawks" <chawks at dls.net>
> wrote:
> 
> > On Sat, 30 Mar 2013 13:37:13 -0500
> > Allen Huffman <alsplace at pobox.com> wrote:
> > ...
> >> What prompted you to use a Teensy rather than the I/O pins already
> >> on the Raspberry Pi? -
> > 
> > 	I figured the simplest way was to build a USB keyboard
> > adapter. I think it was you that mentioned that the Teensy already
> > had the USB mouse and keyboard protocol available. As far as
> > anything else is concerned, it is a 'standard' USB keyboard.
> 
> That makes sense. I do not know enough about the architecture of MESS
> to know how easy it would be to create a new input device for it,
> assuming it even knows about anything other than USB or PS/2 style
> devices.

	I'm not quite sure how to explain, but, I'll try. Mess doesn't
know anything about USB or PS/2. It simply receives input events from
the OS (Linux, OSX, or Winder$ or whatever) and uses the 'device
emulators' code (CoCo in our case) to generate signals that are
expected. In the CoCo's case, when the 'CoCo' scans the keyboard 'PIA',
 the emulator clears or sets the proper 'PIA' bits so that the
'CoCo' sees that a key in the matrix was pressed (the key with the
value of the key that generated the keyboard event). So you'd have
to write a system driver to use the Raspberry Pi's I/O.

> What led you to choose that particular version of MESS? I see, on
> phones and such, they also use a common older version of MAME, so I
> assume there was something that happened in the next release that
> required more than what smaller/older devices could handle.

	Lots of 'stuff' has been added to the later versions. I don't
even use the latest #%*($^ on my regular computer as the 'MIDI' stuff
is so wrapped up I couldn't make it compile without it, even tho none
of the remaining emulated boxes (CoCos, Dragons, and clones) use it.
(And I had all ready stripped down v0.125 for use on my regular
computer.)


Christopher R. Hawks
-- 
Anyway, there's plenty of room for doubt.  It might seem easy enough,
but computer language design is just like a stroll in the park.
    
Jurassic Park, that is.
                -- Larry Wall in <1994Jun15.074039.2654 at netlabs.com>