Browse Prior Art Database

PS/2 Analog Signal I/O Bus Interface Adapter

IP.com Disclosure Number: IPCOM000101511D
Original Publication Date: 1990-Aug-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 1 page(s) / 43K

Publishing Venue

IBM

Related People

Blokkum, DR: AUTHOR [+2]

Abstract

Disclosed is the design for a PS/2 computer family general-purpose analog-signal interface adapter that provides consistent data readings for all models regardless of host I/O bus speed.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 75% of the total text.

PS/2 Analog Signal I/O Bus Interface Adapter

       Disclosed is the design for a PS/2 computer family
general-purpose analog-signal interface adapter that provides
consistent data readings for all models regardless of host I/O bus
speed.

      Resistive proportional input devices for the PS/2 family have
remained unsupported to this time.  These devices include joysticks
and the myriad other forms of linear output transducers available.
Often it is not cost-effective nor necessary to use sophisticated
custom analog-to-digital conversion circuits to achieve the required
interface information.  This design uses the simple
resistance/capacitance (RC) timing constant circuit to convert a
resistive linear signal into an 8-bit resolution digital byte for the
computer to manipulate.  The problem with other attempts at this
process was that the data conversion was dependent upon the machine
cycle speed of the particular host model used.

      Our approach addresses this deficiency by forcing the host
microchannel to execute I/O reads and writes to the adapter at a
fixed, non-machine cycle time-dependent rate. The 14.314 MHz bus
clock was monitored to count a predetermined number of microseconds
before relinquishing bus control back to the system bus master.  This
allows the RC timing circuit to perform a consistent, repeatable data
conversion and do away with the need for input signal calibration.
Prototype testing on all PS/2 models was performed with good resu...