PAN301BSI-208 Datasheet, PDF (15/27 Pages) Pixart Imaging Inc. – CMOS HIGH PERFORMANCE OPTICAL MOUSE SENSOR

PixArt Imaging Inc.
PAN301BSI-208
CMOS Optical Mouse Sensor
6. Serial Interface
The synchronous serial port is used to set and read parameters in the PAN301BSI-208, 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
PAN301BSI-208 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 PAN301BSI-208 in case of an
error.
6.1 Transmission Protocol
The transmission protocol is a two-wire link, half duplex protocol between the micro-controller and
PAN301BSI-208. All data changes on SDIO are initiated by the falling edge on SCLK. The host micro-
controller always initiates communication; the PAN301BSI-208 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 9. Transmission protocol
6.1.1 Write Operation
A write operation, which means that data is going from the micro-controller to the PAN301BSI-208, 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
PAN301BSI-208 reads SDIO on rising edges of SCLK.
SCLK
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
SDIO
DON'T
CARE
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 10. Write operation
6.1.2 Read Operation
A read operation, which means that data is going from the PAN301BSI-208 to the micro-controller, is
always initiated by the micro-controller and consists of two bytes. The first byte contains the address, is
written by the micro-controller, and has a “0” as its MSB to indicate data direction. The second byte
contains the data and is driven by the PAN301BSI-208. The transfer is synchronized by SCLK. SDIO is
All rights strictly reserved any portion in this paper shall not be reproduced, copied or transformed to any other forms without permission.
15
PixArt Imaging Inc.
E-mail: [e-mail]
V1.1, MAY. 2004