[Coco] Arduino as a Mouse/Keyboard interface?

Phill Harvey-Smith afra at aurigae.demon.co.uk
Sun Jul 1 18:06:52 EDT 2012

On 01/07/2012 22:27, Allen Huffman wrote:
> On Jul 1, 2012, at 2:52 PM, Frank Swygert wrote:
> This is actually why I was asking about CoCO keyboard matrix a few
> weeks before CoCoFEST. I had planned to do this very thing and bring
> one to the Fest. But, I still have not gotten to it.
> Yes, it sounds possible with the $30 (less, discount) Arduino boards.
> There is code available to read USB keyboard, and it has I/O lines to
> hook to the keyboard port. I was thinking it may have been one or two
> lines short, though. I did not think of a mouse, but it might have
> analog outs that could do the same thing for a mouse.
> It would be very cheap. RadioShack even sells them.

I've done PS/2 -> Retro computer (including CoCo / Dragon) in the past, 
using an AVR, should be possible to use Arduino, as this is after all 
AVR based.

Rather than hooking the AVR's I/O lines directly to the 6821, a better 
IMHO way of doing it is to have a crosspoint switch in between such as 
the MT8816, the AVR translates the PS/2 (or USB) scancode into a 
row/column, and turns on or off the switch (within the crosspoint) that 
corisponds to the CoCo key you want to press. The output from the 
crosspoint matrix is connected to the CoCo keyboard port.

As far as the CoCo is concerned it has a normal keyboard connected, and 
it doesn't matter what the scanning code on the CoCo does, it just 
"sees" a key depressed and reads it as it would a standard keyboard.



Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !

"You can twist perceptions, but reality won't budge" -- Rush.

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