13

LED Mode

For optimized tracking performance, the LED is in DC

mode when motion is detected, and ADNS-5050 will

pulse the LED when the mouse is in idle state. To force the

LED into always DC mode, kindly refer to register 0x22.

Synchronous Serial Port

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

rameters in the ADNS-5050, and to read out the motion

information.

The port is a three wire serial port. The host micro-con-

troller always initiates communication; the ADNS-5050

never initiates data transfers. SCLK, SDIO, 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).

SDIO:

Input and Output data.

NCS:

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

low to activate the serial port; otherwise, SDIO

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

NCS can also be used to reset the serial port in

case of an error.

Write Operation

1

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

2

1

D0

D5

D6

D7

A0

A1

A2

A3

A4

A5

A6

1A6

D4

D3

D2

D1

SCLK

NCS

SDIO

SDIO DRIVEN BY MICRO-CONTROLLER

SDIO Setup and Hold Time

1/(2f )

SCLK

SCLK

SDIO

1/(2f )

SCLK

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 nor-

mal address-to-data or transaction-to-transaction delay

is still required before beginning the next transaction. To

improve communication reliability, all serial transactions

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 com-

munication and put the chip into an unknown state. In ad-

dition, NCS must be raised after each burst-mode transac-

tion is complete to terminate burst-mode. The port is not

available for further use until burst-mode is terminated.

Write Operation

Write operation, defined as data going from the micro-

controller to the ADNS-5050, is always initiated by the

micro-controller and consists of two bytes. The first byte

contains the address (seven bits) and has a “1” as its MSB

to indicate data direction. The second byte contains the

data. The ADNS-5050 reads SDIO on rising edges of SCLK.

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PixArt Imaging Inc.

PixArt Imaging Inc.

ADNS-5050 Optical Mouse Sensor