ADNS-9500 Avago Technologies US Inc., ADNS-9500 Datasheet - Page 15

• Manufacturer Part Number: ADNS-9500
• Description: Ultimate Gaming Laser Sensor
• Manufacturer: Avago Technologies US Inc.

Specifications of ADNS-9500

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

MOSI
MISO
Synchronous Serial Port
The synchronous serial port is used to set and read param-
eters in the ADNS-9500 Sensor, and to read out the motion
information. The serial port is also used to load PROM data
into the ADNS-9500 Sensor.
The port is a four wire port. The host micro-controller
always initiates communication; the ADNS-9500 Sensor
never initiates data transfers. SCLK, MOSI, 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 are:
Motion Pin
The motion pin is an active low output that signals the
micro-controller when motion has occurred. The motion
pin is lowered whenever the motion bit is set; in other
words, whenever there is data in the Delta_X_L, Delta_XH,
Delta_Y_L or Delta_Y_H registers. Clearing the motion
bit (by reading Delta_X_L, Delta_XH, Delta_Y_L and
Delta_Y_H, or writing to the Motion register) will put the
motion pin high.
SCLK
Figure 13. Write Operation
Figure 14. MOSI Setup and Hold Time
15
SCLK
MOSI
NCS
SCLK: Clock input. It is always generated by the master
(the micro-controller).
MOSI: Input data. (Master Out/Slave In)
MISO: Output data. (Master In/Slave Out)
NCS: Chip select input (active low). NCS needs to be low
to activate the serial port; otherwise, MISO will be high
Z, and MOSI & SCLK will be ignored. NCS can also be used
to reset the serial port in case of an error.
t
setup , MOSI
1
1
2
A
6
t
3
A
Hold,MOSI
5
A
4
4
5
A
3
MOSI Driven by Micro-Controller
6
A
2
7
A
1
A
8
0
9
D
7
10
D
6
11
D
5
12
D
4
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 including PROM download. After a transac-
tion is aborted, the normal 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 inter-
preted as serial communication and put the chip into an
unknown state. In addition, NCS must be raised after each
burst-mode transaction 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-9500 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 ADNS-9500 Sensor reads MOSI on rising
edges of SCLK.
13
D
3
14
D
2
15
D
1
16
D
0
1
1
A
2
6