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AT89RFD-11 User Guide
7648A–USB–06/06
3.2
Sensor
This reference design features the ADNS-3030 optical navigation engine. It contains an
Image Acquisition System (IAS), a Digital Signal Processor (DSP), and a three-wire
Serial Peripheral Interface consists of the serial clock (SCLK), the master-in/slave-out
(MISO) and the master-out/slave-in (MOSI). In addition two signals, Motion, is an output
intended to act as an interrupt to the microcontroller whenever the ADNS-3030 senses
motion, and SHTDWN, is an input pin to set the sensor in shutdown mode. When the
mouse is moved the ADNS-3030 alerts the system controller by activating the Motion
signal. At the same time the ADNS-3030 accumulates the horizontal and vertical dis-
placements (count per inch, or cpi) in its Delta_X and Delta_Y registers respectively.
The ADNS-3030 deactivates the Motion signal as soon as movement stops. The mouse
motion can be also detected by checking if the MOT bit (bit 7 in Motion register) is set.
The SmartSpeed technology automatically optimizes the frame rate by examining the
acquired images of the surface. It also manages the integrated LED driver to coordinate
with the shutter. The system controller reads the motion information and reports it to the
PC to update the cursor position. The advantages of using ADNS-3030 optical sensor
are the efficient power management, high tracking accuracy, and efficient communica-
tions with the optical sensor via the full duplex SPI port. To learn more about sensor’s
technical information, please visit the Avago web site at http://www.avagotech.com
Figure 3-2.
Sensor interface
3.3
Mouse Buttons
Mouse buttons are connected as standard switches. These switches are pulled up by
the pull up resistors inside the microcontroller. When the user depresses a button, the
switch will be closed and the pin will be pulled LOW to GND. A LOW state at the pin is
interpreted as the button being depressed. A HIGH state is interpreted as the button has
been released or the button is not being depressed. In this reference design there are
three switches: left, Z-wheel (middle), and right.
AT89C5131A-M
ATMEL
microcontroller
AVAGO
ADNS-3030
Optical Mouse
Sensor
MOSI
MISO
SCLK
STDW
NCS
MOTION
