PixArt Imaging Inc.

PAW3101DB

CMOS Optical Mouse Sensor

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17

PixArt Imaging Inc.

V3.1 May. 2008

Power On Problem - The problem occurs if the mouse sensor powers up before the mouse controller

sets the SCLK and SDIO lines to be output. The mouse sensor and the mouse controller might get out

of synchronization due to power on problem. An easy way to solve this is to use “watchdog timer

timeout”.

ESD Events - The mouse sensor and the mouse controller might get out of synchronization due to ESD

events. An easy way to solve this is to use “watchdog timer timeout”.

6.3 Collision Detection on SDIO

The only time that the mouse sensor drives the SDIO line is during a READ operation. To avoid data collisions,

the mouse controller should release SDIO before the falling edge of SCLK after the last address bit. The mouse

sensor begins to drive SDIO after the next falling edge of SCLK. The mouse sensor release SDIO of the rising

SCLK edge after the last data bit. The mouse controller can begin driving SDIO any time after that. In order to

maintain low power consumption in normal operation, the mouse controller should not leave SDIO floating until

the next transmission (although that will not cause any communication difficulties).

6.4 Power Down Mode

The mouse sensor can be placed in a power-down mode by setting PD_enh bit in the Operation_Mode register

via a serial port write operation. After setting the Operation_Mode register, wait at least 1frame times. To get the

chip out of the power down mode, clear PD_enh bit in the Operation_Mode register via a serial port write

operation. In the power down mode, the serial interface watchdog timer (see Section 5.2) is not available. But,

the serial interface still can read/write normally. For an accurate report after leave the power down mode, wait

about 3ms before the mouse controller is able to issue any write/read operation to the mouse sensor.

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1

0

1

1

1

2

1

3

1

4

1

5

1

6

SCLK

SDIO

1frame, max

1

0 000

00 0

Address = 0x00

Data = 0x40

010

000 0

0

IDD

Figure 10. Power-down Configuration Register Writing Operation

6.5 Error Detection

1. The mouse controller can verify success of write operations by issuing a read command to the same address

and comparing written data to read data.

2. The mouse controller can verify the synchronization of the serial port by periodically reading the product ID

register.