PixArt Imaging Inc.

PAN3204DB

Wireless Optical Mouse Sensor

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PixArt Imaging Inc.

E-mail: fae_service@pixart.com.tw

V3.0, Apr. 2008

6.1.2 Read Operation

A read operation, which means that data is going from the mouse sensor to the mouse controller, is always

initiated by the mouse controller and consists of two bytes. The first byte contains the address, is written by the

mouse controller, and has a “0” as its MSB to indicate data direction. The second byte contains the data and is

driven by the mouse sensor. The transfer is synchronized by SCLK. SDIO is changed on falling edges of SCLK

and read on every rising edge of SCLK. The mouse controller must go to a high Z state after the last address data

bit. The mouse sensor will go to the high Z state after the last data bit.

SD IO driven by the m ouse controller

SD IO driven by the m ouse sensor

N ote "A "

N ote "B "

Note "A "

7

8

A0

D7

1. T he m ouse controller sends address to the m ouse sensor.

2. T he m ouse controller releases and set SD IO to H i-Z after the last address bit.

9

Note "B "

16

D0

1. T he m ouse sensor sends data to the m ouse controller .

2. T he m ouse sensor releases and set SD IO to H i-Z after the last data bit.

Hi-Z

Hi-Z

1

SC L K

SD IO

SD IO

SC L K

A1

SC L K

SD IO

1

2

3

456

78

10

A5

A4

A3

A2

A1 A 0

D 7

D6

D5

D4

D3

D 2

D1

D0

9

11121314

15

A6

0

D ON'T

CA RE

16

Hi-Z

Hi-Z

R /W bit of next address

SD IO driven by the m ouse controller

R /W bit of next

address

tHOLD

3us,m in

_

_

Figure 9. Read Operation

6.2 Re-Synchronous Serial Interface

If the mouse controller and the mouse sensor get out of synchronization, then the data either written or read from

the registers will be incorrect. In such a case, an easy way to solve this condition is to toggle the SCLK line from

high to low for least tRESYNC, and then MUST toggle it from low to high to wait at least tSIWTT to reach re-

synchronous the serial port. This method is called by “watchdog timer timeout”. The mouse sensor will reset the

serial port without resetting the registers and be prepared for the beginning of a new transmission.

SC L K

tSIW TT

1

2345

678

9

1

0

1

1

1

2

1

3

1

4

1

5

1

6

SD IO

Hi-Z

A DDRES S (R /W )

DAT A

tRESYNC

1u s, m in

_

Figure 10. Re-synchronous Serial Interface Using Watchdog Timer Timeout

Note that this function is disabled when the mouse sensor is in the power down mode. If the user uses this

function during the power down mode, it will get out of synchronization. The mouse sensor and the mouse

controller also might get out of synchronization due to following conditions.