Browse Prior Art Database

LOW COST METHOD FOR ADDING USB KEYBOARD AND MOUSE SUPPORT TO LAPTOP AND DESKTOP PCS.

IP.com Disclosure Number: IPCOM000014533D
Original Publication Date: 2001-Feb-10
Included in the Prior Art Database: 2003-Jun-19
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Abstract

LOW COST METHOD FOR ADDING USB KEYBOARD AND MOUSE SUPPORT TO LAPTOP AND

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  LOW COST METHOD FOR ADDING USB KEYBOARD AND MOUSE SUPPORT TO LAPTOP AND DESKTOP PCS.

LOW COST METHOD FOR ADDING USB KEYBOARD AND MOUSE SUPPORT TO LAPTOP AND

DESKTOP PCS.

Background: USB (a desktop serial bus) is an emerging standard for PC
connectivity technology. One of its advantages is that it frees up a scarce
system resource (e.g. processor interrupts) by consolidating the functions
served by the keyboard, mouse, serial, and parallel ports (and more...) on
a single sharable bus thereby placing them on a single, sharable interrupt.

Problem:
USB keyboards and mice are currently costly, hence the transition from PS/2
to USB will be slow for PC manufacturers. Also, USB poses a challenge for
Legacy operating systems (Windows 3.1, Sun OS, etc) since these operating
systems don't support USB (and probably never will). This support can be
implemented by BIOS vendors, but legacy device support (keyboard/mouse) in
BIOS is a large development expense, plus it takes up a large amount of
BIOS run-time memory (more than 48K).

This idea modifies the current keyboard controller in Laptop and Desktop
computers by adding USB endpoint logic to the keyboard controller already
present on the system planar.

Consider the following scenarios:
Scenario A: Non USB aware O.S. -Keyboard controller functions in a "Legacy"
mode using I/O 60h&64h, and Int. 1 & 12. The USB endpoint that has been
added to the keyboard controller is never used, so the controller always
uses I/O 60h&64h and Int.1&12
Scenario B...