25

Notes for Motion:

1. Reading this register freezes the Delta_X and Delta_Y register values. Read this register before reading the Delta_X and Delta_Y registers. If

Delta_X and Delta_Y are not read before the motion register is read a second time, the data in Delta_X and Delta_Y will be lost.

2.

PixArt Imaging RECOMMENDS that registers 0x02, 0x03 and 0x04 be read sequentially. See Motion burst mode also.

3. Internal buffers can accumulate more than eight bits of motion for X or Y. If either one of the internal buffers overflows, then absolute path data

is lost and the OVF bit is set. This bit is cleared once some motion has been read from the Delta_X and Delta_Y registers, and if the buffers are

not at full scale. Since more data is present in the buffers, the cycle of reading the Motion, Delta_X and Delta_Y registers should be repeated

until the motion bit (MOT) is cleared. Until MOT is cleared, either the Delta_X or Delta_Y registers will read either positive or negative full scale.

If the motion register has not been read for long time, at 1800 cpi it may take up to 72 read cycles to clear the buffers, at 3

600 cpi, up to 140

cycles. Alternatively, writing to the Motion_Clear register (register 0x12) will clear all stored motion at once.

Delta_X

Address: 0x03

Access: Read

Reset Value: 0x00

Bit

76543210

Field

Data Type: Eight bit 2’s complement number.

USAGE: X movement is counts since last report. Absolute value is determined by resolution. Reading clears the register.

Delta_Y

Address: 0x04

Access: Read

Reset Value: 0x00

Bit

7

6

54

32

1

0

Field

Data Type: Eight bit 2’s complement number.

USAGE: Y movement is counts since last report. Absolute value is determined by resolution. Reading clears the register.

00

01

02

7E

7F

+127

+126

+1

+2

FF

FE

81

80

0

-1

-2

-127

-128

Motion

Delta_X

00

01

02

7E

7F

+127

+126

+1

+2

FF

FE

81

80

0

-1

-2

-127

-128

Motion

Delta_Y

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PixArt Imaging Inc.

PixArt Imaging Inc.