Browse Prior Art Database

Three-Button TrackPoint Type Pointing Device

IP.com Disclosure Number: IPCOM000116033D
Original Publication Date: 1995-Jul-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Barker, JH: AUTHOR [+3]

Abstract

Disclosed is a TrackPoint* type pointing device emulating a three-button mouse. The effect of two buttons is provided in a conventional way by a pair of buttons located at the lower border of the keyboard frame. The effect of the third button is provided through the use of a force-sensing transducer located under the pointing stick.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 65% of the total text.

Three-Button TrackPoint Type Pointing Device

      Disclosed is a TrackPoint* type pointing device emulating a
three-button mouse.  The effect of two buttons is provided in a
conventional way by a pair of buttons located at the lower border of
the keyboard frame.  The effect of the third button is provided
through the use of a force-sensing transducer located under the
pointing stick.

      The force-sensing transducer, which is preferably separated
from the pointing stick by a motion-transfer material, such as
silicon rubber, produces an analog output as a force is applied.
This output is sent through an operational amplifier to provide
switch open and switch closed signals, which are sent to the
microcontroller.  Specifically, these signals may be fed to an
Analog/Digital channel of the microcontroller, or an interrupt can be
sent to the microcontroller to signal a button operation.

      In the three-byte mouse data packet of an IBM* PS/2* system,
bit 2 of the first byte is dedicated for the middle button status.
Since the TrackPoint II* pointer system has only two buttons, this
middle button bit is conventionally always zero.  To implement a
three-button TrackPoint system, each of the three buttons is assigned
to a bit.  Without the application of tangential force to the
pointing stick to simulate mouse movement, the value of the first
byte for a conventional TrackPoint II system is 9h through Bh, while
in the three-button system this value is 9h thro...