Apple Lisa - Mouse; Mouse Commands

Confidential
Lisa Hardware Reference Manual
THE MOUSE
The mouse is an input device with motion sensors and one or more
buttons. It sends movement and button information to the computer
through the 6522 on the keyboard interface. This information is
usually used to provide a fast and convenient pointing and drawing
mechanism
by tracking the mouse movement in some direct manner with a
cursor on the screen.
The mouse is plugged into the nine pin EIA connector in the. middle of
the connector panel on the back of the Lisa. Since the mouse senses
the mechanical movement of the ball as it rolls across a table, it
should work on almost any convenient surface.
1
MOUSE CONNECTOR PINOUT
- Switch
L
•••••
5 4 3 2 1
••••
g 8 7 6
6
- No connection
7-Jul-81
2
- +5v
7
- Switch 0 (always grounded by
mouse)
3
- Ground
8
- Down
4
-
Left
9
- Up
5
-
Right
MOUSE OJMMANDS
Mouse commands are sent to the 6522 Peripheral A Port data bus
(PAD-PA7). The command format is:
0111 ennn
If e is set, mouse interrupts are enabled. The nnn bits set the
time interval that will separate mouse interrupts.
Once mouse interrupts are enabled and the time interval has been set,
the COPS interrupts the 68000 whenever the mouse moves. The time
between interrupts is about 4 ms times the number given in the nnn
bits. For example, the command 01111100 ($7C) enables the mouse to
interrupt 16 ms (100 = 4*4 ms) after the mouse begins to move. If
the mouse continues to move, interrupts are generated every 16 ms.
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