PixArt Imaging Inc.
PAN301BSI-208
CMOS Optical Mouse Sensor
5.2 Quadrature Output State Machine
The following state machine shows the states of the quadrature output pins. The three things to note are
that state 0 is entered after a power on reset. While the PD pin is asserted, the state machine is halted.
Once PD is de-asserted, the state machine picks up from where it left off. During times of mouse no
movement will entry power saving mode, until mouse was moved.
PD
POWER ON RESET
STATE 0
( 0 , 0 )
X/Y output
STATE
XA/YA XB/YB
0
1
2
3
0
0
1
1
0
1
1
0
STATE 1
( 0 , 1 )
STATE 3
( 1 , 0 )
PD
PD
STATE 2
( 1 , 1 )
PD
Figure 7. State machine
5.3 Quadrature Output Waveform
The following diagrams show the waveform of the two channel quadrature outputs. If the X, Y is
motionless, the (XA, XB), (YA, YB) will keep in final state. Each state change (ex. STATE2 → STATE3)
is one count.
X MOTION TO THE RIGHT
Y MOTION UP
( + DIRECTION )
XA/YA
XB/YB
STATE3
( 1 , 0 )
STATE0
( 0 , 0 )
STATE1
( 0 , 1 )
STATE2
( 1 , 1 )
STATE3
( 1 , 0 )
STATE0
( 0 , 0 )
+1
+1
+1
+1
+1
MOTION COUNT
X MOTION TO THE LEFT
Y MOTION DOWN
( - DIRECTION )
XA/YA
XB/YB
STATE1
( 0 , 1 )
STATE0
( 0 , 0 )
STATE3
( 1 , 0 )
STATE2
( 1 , 1 )
STATE1
( 0 , 1 )
STATE0
( 0 , 0 )
-1
-1
-1
-1
-1
MOTION COUNT
Figure 8. Quadrature output waveform
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PixArt Imaging Inc.
14
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V1.1, MAY. 2004
PIXART [ PIXART IMAGING INC. ]
