Browse Prior Art Database

Analog Joystick Interface Emulation using a Digital Counter

IP.com Disclosure Number: IPCOM000113297D
Original Publication Date: 1994-Aug-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 87K

Publishing Venue

IBM

Related People

Moeller, DL: AUTHOR [+2]

Abstract

Described is a circuit implementation which provides analog control joystick interface emulation using a digital counter for use with Personal Computer (PC) game control adapters. The implementation improves joystick game operations by providing digital control enhancements while maintaining compatibility with software written for analog control joystick operations.

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Analog Joystick Interface Emulation using a Digital Counter

      Described is a circuit implementation which provides analog
control joystick interface emulation using a digital counter for use
with Personal Computer (PC) game control adapters.  The
implementation improves joystick game operations by providing digital
control enhancements while maintaining compatibility with software
written for analog control joystick operations.

      In prior art, PC game control adapters generally provided an
interface for two analog controlled joysticks.  Resistive inputs were
provided to the adapter by each joystick so that lever positions
could be determined by converting the resistive inputs to variable
length digital pulses by way of timers.  Software would trigger
timers and continuously poll the interface to measure the length of
the timing pulses.  The concept described herein implements digital
controlled joystick operation so as to improve the speed and
performance of joystick operation.  The concept not only provides
faster operation, but in addition maintains compatibility with
software written for older analog controlled joystick adapters.

      There are disadvantages in using the prior art analog
controlled joysticks as compared to using digitally controlled
joysticks.  The performance of the software using an analog interface
is slowed because of the necessity to trigger and to poll the
interface in determining the length of the converted pulses, whereas
digital controlled joysticks dispense with the need for resistive
signals and provide simple on/off switching outputs.  Digital
controlled joysticks only require a read signal from an input port to
determine the position of the joystick levers.  Analog controlled
joysticks require a large portion of the application code to be
dedicated to calibrate the joystick and to maintain acceptable
operation.  Digital controlled joysticks do not require this type of
coding since the assembly consists of on/off switches.

      Although a simple solution would be to p...