MOUSE(7) MOUSE(7)
NAME
mouse - optical mouse specifications
DESCRIPTION
Signals: The serial data interface signal level is
compatible with RS-423 which has roughly a 10V swing
centered about ground. The idle state and true data bits
for the interface are Mark level or -5V whereas false data
bits and the start bit are spaces or +5V. The serial data
is transmitted at 4800 baud with one start bit, eight data
bits, and no parity.
Protocol: The mouse provides a five-byte data block whenever
there is a change of position or button state. The first
byte is a sync byte which has its upper five bits set to
10000 and its lower three bits indicating the button states
where a 0 indicates depression. The sync byte looks like
this: 10000LMR. The next four bytes contain two difference
updates of the mouse's change in position: X1, Y1, X2, and
Y2. Positive values indicate movement to the right or
upward. System software ignores bytes beyond the first five
until reception of the next sync byte.
Connector Pin Assignment:
______________
|PIN | SIGNAL |
______________
| | |
1 +5V
| | |
9 GND
| | |
5 MTXD
| | |
3 -5V
|____|________|
ORIGIN
Silicon Graphics, Inc.
Page 1 (last mod. 8/20/87)