Mouse/ Trackerball Specification; Data Rate; Data Flow; Optional Byte - Philips CDl660 Technical Documentation Manual

3.3 MOUSE/TRACKERBALL specification
3.3.1 Data rate
Baudrate: 1200 baud.
3.3.2 Data flow
During normal operation (RTS asserted) :
• Data is received by the CD-i player via RXD.
• Every time there is a mouse movement or a button state
change, the three byte mouse data is transmitted from mouse
to CD-i player.
• When the mouse is not moved and the buttons do not change
state (they stay as they are, pressed or released), the mouse
should not send any 3 byte mouse data to the CD-i player.
• An
on going data packet transmission should not be
interrupted by a button state change or a mouse position
change.
3. INPUT DEVICES
3.3.3 Data format
• 1 startbit
• 7 databits (LSB first)
• 2 stopbits
d6 d5 d4 d3 d2 dl
Byte 0 1 btl
bt2
Y7 Y6 X7
Byte 1
0 XS
X4
X3
X2 Xl
Byte 2
0 YS
Y4
Y3
Y2 Yl
Byte 3 optional
• btl = buttonl: 1 = pressed
• bt2 = button2: 1 = pressed
0 = not pressed.
0 = not pressed.
• X7 ..
XO:
• 8 bit data horizontal movement.
• 2's complement.
• left direction
=
negative ($FF .. $80).
• right direction = positive ($01..$7F).
• Y7 .. YO:
• 8 bit data vertical movement.
• 2's complement.
• up direction = negative ($FF .. $80) .
• down direction = positive ($01..$7F).
dO
X6
XO
YO
A databyte = $00 indicates that there was no movement in that
direction.
3.3.4 Optional byte 3
• This optional byte indicates a Player control Key (PCK).
PCK (6 bit) is applicable (see 3.8 PCK table for values).
• Note : d6 is 0.
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