Typical Application Circuit Diagram - I.C. Top View
The PA03xyz mouse controller I.C. is Microsoft Wheel Mouse
compatible and can work with standard Microsoft Mouse Drivers or with the
Wheel Mouse Drivers if you have them. It uses analog voltage levels to control mouse
cursor movement instead of the usual optical encoder inputs. This makes it
easy to use the controller to build special devices to enable handicapped
or disabled people to control their computer mouse functions. It is also
easy to use it to build special mouse controllers for use in computer
applications where a standard mouse would not work such as industrial
environments. This I.C. has been used mostly with joysticks. These have
been both standard potentiometer type and hall effect type joysticks. Of
course any voltage source can be used. This would include, accelerometers
for tilt sensing, solid state gyros for rotation sensing and photosensors
for light sensing and various devices like Koala pads to name a few.
The analog voltage inputs control the mouse cursor motion, direction and
speed. The analog inputs have a range of 0 to 5 volts. The zero motion value
is 2.5 volts with an adjustable deadband. The deadband is a fixed value of
15% of range above 2.3 volts on the deadband input.
It varies from 0 to 50% of range from 0 to 1.25 volts
(+/- 25% of 5 volts). The I.C.s are available with a selection of motion
direction. For example the PA03RDD moves the cursor Right on a voltage
higher than the deadband on the X axis, Down on a voltage higher than the
deadband on the Y axis, and Scrolls Down on a voltage higher than the
deadband on the Z axis. Below the deadband zone the cursor moves in the
opposite direction. Cursor speed is proportional to the deviation from the
deadband. Typically the cursor can cross the screen in less than 1 second at
The PA03xyz has a unique sliding window mode thats selected with
pin 11. When pin 11 is held low the deadband function becomes the sliding
window function. The deadband input sets the window size. Within the
"window" the cursor movement is proportional to the voltage change on the
analog inputs. The positioning is more like absolute positioning. For
example on a joystick if you move the stick a little to the left the cursor
moves a little to the left. The cursor stops moving if the joystick stops
moving. If the joystick is moved beyond the "window" zone the cursor movement
reverts to the relative mode and it "slides" at a speed proportional to the
deviation from the window. The effect is that the absolute positioning
window can be slid around to any area of the screen no matter the size or
resolution. The "window" typically can be as much as 4 inches square
depending on the deadband/window size input voltage.
The switch inputs provide: LEFT BUTTON DOUBLE-CLICK, LEFT BUTTON,
RIGHT BUTTON, MIDDLE BUTTON, DRAG-N-DROP, WINDOW MODE SELECT and
The DRAG-N-DROP input effectively locks down the left button for a drag
operation. Activating any button input or the DRAG-N-DROP input a second
time releases the left button and ends the drag operation. The optional LED
(Light Emitting Diode) shown in the DRAG-N-DROP pull-up lights during the
drag and drop operation.
The Z-AXIS SELECT switch functions in Wheel Mouse (3D) mode to switch the
Y-Axis analog voltage input to control the Z-Axis. The Z-Axis input can be
tied to 2.5 volts with two resistors if that input isn't used. Z-Axis
functions depend on system settings and the particular applications that use
the data. It is often used to control scroll bars or for IN and OUT movement
in 3D applications.
The switches are wired with a common negative (pull down to activate).
External circuitry can also be used in place of switches so the mouse
controller can be controlled by another device (i.e. another
microcontroller, photosensors etc...). Note that the DRAG-N-DROP pin 10 is
both an input and an output. When interfacing pin 10 to external circuitry
there should be no active pull-up. The I.C. is available in a version
without the LED option so pin 10 is always an input and active high
circuitry can used. Otherwise a open collector can be used for interface.
The price of the PA03xyz PS/2 Analog Input Mouse Controller I.C. is $20.00.
Quantity pricing is available.