EMERSON - KEYBOARD/MOUSE DEMO
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Ben Ryves, February 2006

This will only run on the TI-83 Plus. The AT protocol routines are not TI-83 friendly, yet.

You need to plug a PS/2 keyboard or mouse into your calculator, and power it externally.
The wiring is the same as Cullen Ashford Logan's keyboard demo; with pin 5 (clock) going
to tip (red), pin 1 (data) going to ring (white), pin 3 (gnd) going to base (braid) and
pins 4 and 3 (vcc/gnd) connected up to a 5V power supply.

My mouse was quite fussy, unlike my keyboard, and didn't work at 4.5V. It powered up and sent the
acknowledgement bytes, but refused to send position information until I wound the PSU up to 6V.

Using the demos is quite easy. Press CLEAR at any time to quit. 

Mouse: It will sit at a screen saying "waiting" until the mouse sends the correct response to
a sequence of commands resetting and configuring the mouse. Once done, you should end up at a 
screen with a large black mouse cursor on it. Moving the mouse should move this cursor around.
If the mouse becomes disconnected, or loses power, the calculator gets a bit confused. Press [2nd]
to set the mouse back up again.

Keyboard: Control the sprite with the keypad on the calculator, or with the cursor keys of a
connected keyboard. Press [2nd] on the TI to configure the keys; press the keyboard key at the
prompts (for example: press [2nd] then type WASD).

If the mouse refuses to connect, try powering it down, then start the program with the mouse connected
but switched off. Switch it on when you see "Waiting...", and it should initialise. Failing that,
check that clock and data lines are correct, and that you are giving your mouse 5V.

I claim no responsibility for damaged calculators and/or mouse and/or keyboards.