PAW3602DH-NF Datasheet, PDF (14/33 Pages) Pixart Imaging Inc. – CMOS LASER MOUSE SENSOR

PixArt Imaging Inc.
PAW3602DH-NF
CMOS Laser Mouse Sensor
7. Serial Interface
The synchronous serial port is used to set and read parameters in the mouse sensor, and can be used to read out
the motion information instead of the quadrature data pins.
SCLK: The serial clock line. It is always generated by the host micro-controller.
SDIO: The serial data line used for write and read data.
PD: A third line is sometimes involved. PD (Power Down pin) is usually used to place the mouse sensor in a
low power mode to meet USB suspend specification. PD can also be used to force re-synchronization
between the micro-controller and the mouse sensor in case of an error.
7.1 Transmission Protocol
The transmission protocol is a two-wire link, half duplex protocol between the micro-controller and mouse
sensor. All data changes on SDIO are initiated by the falling edge on SCLK. The host micro-controller always
initiates communication; the mouse sensor never initiates data transfers.
The transmission protocol consists of the two operation modes:
- Write Operation.
- Read Operation.
Both of the two operation modes consist of two bytes. The first byte contains the address (seven bits) and has a
bit7 as its MSB to indicate data direction. The second byte contains the data.
FIRST BYTE
SECOND BYTE
R /W
(1 BIT)
ADDRESS (7 BIT)
DATA (8 BIT)
MSB
LSB MSB
LSB
Figure 7. Transmission protocol
7.1.1 Write Operation
A write operation, which means that data is going from the micro-controller to the mouse sensor, 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 transfer is synchronized
by SCLK. The micro-controller changes SDIO on falling edges of SCLK. The mouse sensor reads SDIO on
rising edges of SCLK.
SCLK
SDIO
DON'T
CARE
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
1
A6 A5 A4 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0
DON'T
CARE
SDIO driven by Micro-controller
Figure 8. Write operation
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PixArt Imaging Inc.
E-mail: [e-mail]
V1.0, Jun. 2007