16

Burst Mode Operation

Burst mode is a special serial port operation mode that

may be used to reduce the serial transaction time for a

motion read. The speed improvement is achieved by con-

tinuous data clocking to or from multiple registers with-

out the need to specify the register address, and by not

requiring the normal delay period between data bytes.

Burst mode is initiated by reading the MOTION_BURST

register (0x63). The ADNS-3000 will respond with the

contents of the DELTA_X, DELTA_Y, SQUAL, SHUT_HI,

SHUT_LO, and PIX_MAX and PIX_ACCUM registers in that

order. The burst transaction can be terminated anywhere

in the sequence after the DELTA_Y value by bringing the

NCS pin high. The default value in BURST_READ_FIRST

register (0x42) is the address of the DELTA_X register. The

address that is specified in the BURST_READ_FIRST regis-

ter can be changed to address 0x00 – 0x02 (PROD_ID –

MOTION_ST) or 0x05 – 0x08 (SQUAL – PIX_MAX).

In 12-bit motion reporting there will be an extra content

in DELTA_XY_HIGH (register 0x0c), to be read out in the

order of DELTA_X, DELTA_Y,  DELTA_XY_HIGH, SQUAL,

SHUT_HI, SHUT_LO, PIX_MAX and PIX_ACCUM. The rest

of the burst mode operation is the same as 8-bit motion

reporting.

After reading the MOTION_BURST address (0x63), the

the continuous data bytes. All data bits can be read with

no delay between bytes by driving SCLK at the normal

rate. The data are latched into the output buffer after the

last address bit is received. After the burst transmission is

complete, the micro-controller must raise the NCS line for

not available for use until it is reset with NCS, even for a

second burst transmission.

Reset

During power-up, the ADNS-3000 does not need a pow-

er on reset as there is an internal circuitry that performs

power on reset in the sensor. However it can be reset by

writing 0x5a to register 0x3a. A full reset will thus be ex-

ecuted and any register settings must be reloaded.

Power Down

The ADNS-3000 can be set to Power Down mode by writ-

ing 0x02 to register 0x0d to disable the sensor. In addi-

tion, the SPI port should not be accessed during power

down. Other ICs on the same SPI bus can be accessed,

as long as the sensor’s NCS pin is not asserted. The table

below shows the state of various pins during power down.

To exit Power Down, write 0x5a to register 0x3a to reset

the sensor in order to wake it up. A full reset will thus be

register settings must then be reloaded.

Pin

During Power Down

MOTION

Undefined

NCS

MISO

Undefined

SCLK

MOSI

XY_LED

Low current

Notes:

1. NCS pin must be held to 1 (HIGH) if SPI bus is shared with other

devices. It can be in either state if the sensor is the only device in

connected to the host micro-controller.

2. Reading of registers should only be performed after exiting from the

power down mode. Any read operation during power down will not

reflect the actual data of the registers.

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PixArt Imaging Inc.

PixArt Imaging Inc.

ADNS-3000 Low Power Optical Mouse Sensor