PixArt Imaging Inc.

PAN301A

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.

STATE 0

( 0 , 0 )

POWER ON RESET

STATE 1

( 0 , 1 )

STATE 3

( 1 , 0 )

STATE 2

( 1 , 1 )

PD

STATE

X/Y output

XA/YA XB/YB

0

1

2

3

00

0

1

1

1

10

PD

PD

PD

5.3 Quadrature Output Waveform

Figure 7. State machine

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.

XA/YA

XB/YB

X MOTION TO THE RIGHT

Y MOTION UP

( + DIRECTION )

STATE0

( 0 , 0 )

STATE1

( 0 , 1 )

STATE2

( 1 , 1 )

STATE3

( 1 , 0 )

+1

+1

+1

+1

MOTION COUNT

STATE3

( 1 , 0 )

STATE0

( 0 , 0 )

+1

XA/YA

XB/YB

X MOTION TO THE LEFT

Y MOTION DOWN

( - DIRECTION )

STATE0

( 0 , 0 )

STATE3

( 1 , 0 )

STATE2

( 1 , 1 )

STATE1

( 0 , 1 )

-1

-1

-1

-1

MOTION COUNT

STATE1

( 0 , 1 )

STATE0

( 0 , 0 )

-1

Figure 8. Quadrature output waveform

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PixArt Imaging Inc.

V1.3, MAY. 2004