2
RF Board
Left Button
Avago
ADNS-3040
Optical Mouse
Sensor
Wheel Button
Right Button
Z Optics
TI
MSP430F1222
Microcontroller
MISO
MOSI
SCLK
NCS
Control
and Data
MAX1722
Boost Regulator
Quadrature
Signals
Lens
Image
Array
LED
Lens
Surface
Shadow pattern
Figure 2. Illustration of Optical Navigation technology
Reference Design Overview
The image-based optical mouse sensor takes snap shots
of the surface it is navigating on. It measures changes in
position by comparing the sequential images (frames) and
mathematically determines the direction and magnitude
of movement. The traditional duel-channel optical
encoder generates the quadrature Z-wheel movement
signals. This design guide illustrates the hardware con-
nection of a LED-based optical mouse with standard con-
figuration; as well as the firmware management and the
handling of the USB protocols. USB protocol provides a
standard way of reporting mouse movement and button
presses to the PC. The Windows HID driver interprets the
USB data and performs the cursor movements and mouse
clicks.
The functional block diagram of the reference design
mouse is shown in Figure 1. The optical sensor detects
the X and Y movements. An optical quadrature encoder
provides the Z-wheel movement. Each of the button
switches is pulled up normally and provides a Ground
when pressed. The MAX1722 boost regulator maintains
the 2.7 V operating voltage for the reference design
mouse from two regular AA Alkaline batteries in parallel.
Theory of Operation
Navigation Technology
The heart of the ADNS-3040 navigation sensor is a CMOS
image array. An LED and an optical system illuminate
the surface that the ADNS-3040 is navigating on. The
texture of the surface casts bright and dark spots forming
distinct images as the sensor is moved across the surface.
A Digital Signal Processing (DSP) engine and its built-in
algorithm evaluate these images and determine the
magnitude and direction of the movement. The motion
data is made available in the delta_X and delta_Y registers
for the system controller to retrieve. An extensive power
saving topology is implemented within the ADNS-3040
navigation engine. A Motion pin (output) is available to
act as the system interrupt. As long as there is no motion
the system can remain in Sleep mode allowing maximum
battery power saving. Based on the last detected motion
the ADNS-3040 navigation engine enters various power
saving modes when no new motion occurs. These power
saving features make the ADNS-3040 ideally for wireless
applications.
Figure 1. ADNK-3043-ND24 Reference Design Mouse functional Block Diagram
