16

VCSEL’s Typical Characteristics

Figure 13. Forward Voltage vs. Forward Current for VCSEL

Figure 14. Junction Temperature Rise vs. Forward Current for VCSEL

Motion Pin Timing

The motion pin is a level-sensitive output that signals the

micro-controller when motion has occurred. The motion

pin is lowered whenever the motion bit is set; in other

words, whenever there is data in the Delta_X or Delta_Y

registers. Clearing the motion bit (by reading Delta_X

and Delta_Y, or writing to the Motion register) will put

the motion pin high.

LASER Mode

For power savings, the VCSEL will not be continuously on.

ADNS-7530 will flash the VCSEL only when needed.

Synchronous Serial Port

The synchronous serial port is used to set and read pa-

rameters in the ADNS-7530, and to read out the motion

information. The port is a four-wire port.

The host

micro-controller always initiates communication; the

ADNS-7530 never initiates data transfers. SCLK, MOSI,

and NCS may be driven directly by a micro-controller.

The port pins may be shared with other SPI slave devices.

When the NCS pin is high, the inputs are ignored and the

output is tri-stated.

The lines that comprise the SPI port:

SCLK:

Clock input. It is always generated by the master

(the micro-controller).

MOSI:

Input data. (Master Out/Slave In)

MISO:

Output data. (Master In/Slave Out)

NCS:

Chip select input (active low). NCS needs to be

low to activate the serial port; otherwise, MISO

will be high Z, and MOSI & SCLK will be ignored.

NCS can also be used to reset the serial port in

case of an error.

Chip Select Operation

The serial port is activated after NCS goes low. If NCS

is raised during a transaction, the entire transaction is

aborted and the serial port will be reset. This is true for

all transactions. After a transaction is aborted, the normal

address-to-data or transaction-to-transaction delay is

still required before beginning the next transaction. To

improve communication reliability, all serial transac-

tions should be framed by NCS. In other words, the port

should not remain enabled during periods of non-use

because ESD and EFT/B events could be interpreted as

serial communication and put the chip into an unknown

state. In addition, NCS must be raised after each burst-

mode transaction is complete to terminate burst-mode.

The port is not available for further use until burst-mode

is terminated.

0.0

0.5

1.0

1.5

2.0

2.5

02

46

8

10

V = A,V

V = C

0

10

20

30

40

50

0123 4 5 6789 10 11 12 13 14 15

V = C

V = A,V

PixArt Imaging Inc.

ADNS-7530 Integrated Molded Lead-Frame DIP Sensor

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PixArt Imaging Inc.