34

LP_CFG0

Address: 0x22

Access: R/W

Reset Value: Undefined

Bit

76543210

Field

LP7

LP6

LP5

LP4

LP3

LP 2

LP 1

LP 0

Data Type: 8-bit unsigned integer

USAGE:

This register is used to set the laser current. It is to be used together with LASER_CTRL1 register, where it

contains the complement of LASER_CTRL0 register. If the registers do not contain complementary values,

the laser is turned off and the LP_VALID bit in the MOTION register is set to 0.

For testing purpose, the laser power can be changed by following the Laser Power Adjustment Procedure.

Field Name

Description

LP[7:0]

Controls the 8-bit DAC for adjusting laser current.

For Range 0.8 - 4mA

One step is equivalent to (1/295) x 100% = 0.34% change of relative laser current.

For Range 4 - 10mA

One step is equivalent to (1/365) x 100% = 0.27% change of relative laser current.

Refer to the table below for examples of relative laser current settings.

Range 0.8 - 4mA (Range = 0)

Range 4 - 10mA (Range = 1)

Relatives

Laser Current

LPCFG0

LPCFG1

Relatives

Laser Current

LPCFG0

LPCFG1

13.56%

0x00

0xFF

30.14%

0x00

0xFF

13.90%

0x01

0xFE

30.41%

0x01

0xFE

14.24%

0x02

0xFD

30.68%

0x02

0xFD

..

..

..

..

..

..

..

..

..

..

..

..

99.32%

0xFD

0x02

99.45%

0xFD

0x02

99.66%

0xFE

0x01

99.73%

0xFE

0x01

100.00%

0xFF

0x00

100.00%

0xFF

0x00

* Important Note - Do not adjust the laser current > 7mA

PixArt Imaging Inc.

Track-on-Glass Laser Sensor

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PixArt Imaging Inc.