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Programming information

Last update: Tuesday, May 11, 2004 21:26:14

KeyMouse low level information

During development of Quijote, I discovered the following low level information about the PCW KeyMouse.

In the last 16 bytes of bank 3 (keyboard mapping):

0xBFFB	Bit 7 is the middle button status (1=pressed).
0xBFFD	Bits b4 to b0 are the low bits of the vertical movement counter.

Then, plus the addition of the very valuable information showed in the Richard Fairhurst website the low level interface of PCW KeyMouse is:

0xBFFB	b7: middle button status b6 to b0: horizontal movement counter
0xBFFC	b7 to b6: high bits of vertical movement counter
0xBFFD	b4 to b0: low bits of vertical movement counter
0xBFFE	b7: left button status b6: right button status

For button status: Bit = 1 if button pressed, otherwise = 0.

Values for movement counters: 0 to 127, but when 0 is decreased in 1, 127 is the result, and when 127 is increased in 1, 0 is the result.