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PIA

From CoCopedia - The Tandy/Radio Shack Color Computer Wiki
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The Peripheral Interface Adapter is a chip, of which there are two in your CoCo, that is used for handling I/O, amongst other things.


Keyboard

The keyboard can be scanned through PIA-1 by pulling two values from addresses $FF00 and $FF02. Color Basic ROM, when running a prompt, converts these to ASCII values to be printed to the screen at cursor position. The first address ($FF00) represents the keyboard rows as well as the joystick button, and the second address ($FF02) the keyboard columns. These two value correspond to ASCII values according to the following table:

0 1 2 3 4 5 6 7
0
1
2
3
4
5
6
7

(under construction)