Browse Prior Art Database

Data In/ Data Out Expander

IP.com Disclosure Number: IPCOM000121484D
Original Publication Date: 1991-Sep-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Nahata, P: AUTHOR [+2]

Abstract

This article describes a technique and hardware implementation to enable expansion of the input/output (I/O) capability in a personal computer system without requiring an additional card slot.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 57% of the total text.

Data In/ Data Out Expander

      This article describes a technique and hardware
implementation to enable expansion of the input/output (I/O)
capability in a personal computer system without requiring an
additional card slot.

      In a personal computer system which has four expansion slots
the number of external cards that can be installed in the system is
limited.  The scheme disclosed herein allows the expansion of Data
In/ Data Out (DI/DO) capability within the number of slots available.

      In the disclosed expansion scheme, a commercially available
DI/DO card with maximum 72 I/O points is used, thereby being limited
to controlling only 72 I/O points. When more I/O points need to be
controlled, no card slot is available.  The scheme of this disclosure
allows expansion of the I/O capability without requiring additional
card slots.

      In the 72-I/O-point card only 52 I/O points are for expansion.
These 52 points are divided into four groups as follows:
      a)   Input address  (10 lines)
      b)   Output address (10 lines)
      c)   Data in        (16 lines)  } 4 groups
      d)   Data out       (16 lines)
      e)   In strobe      (1 line)
      f)   Out strobe     (1 line)

      Having divided the card into four groups as shown in the
drawing, the input address and data lines run to all the input
relay/sensor card banks.  Similarly all the output address and data
lines...