Browse Prior Art Database

Compatible Address-Extension for a Serial Interface

IP.com Disclosure Number: IPCOM000115448D
Original Publication Date: 1995-May-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 56K

Publishing Venue

IBM

Related People

Haess, J: AUTHOR [+4]

Abstract

Serial interfaces, which are implemented in computers, are typically used for support functions (e.g., reset of the system, scaning of the shift chains, bootstrap-loading,...).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Compatible Address-Extension for a Serial Interface

      Serial interfaces, which are implemented in computers,  are
typically used for support functions (e.g., reset of the system,
scaning of the shift chains, bootstrap-loading,...).

      These functions have low speed requirements and in the past had
to be implemented with little circuit count.  Therefore the address
ranges supported were quite restrictive, tailored to the system
requirements of a particular system.

      Due to the rapid progress of the technology, new systems need
much larger address ranges for support functions (e.g., number of
shift chains proportional to the number of circuits of a system) than
previous systems did.

      If components of a previous system should be reused in a new
developed system, the problem of the compatibility of the serial
interfaces of the "old" components and the new system comes up.  The
old system had an address range of 256 addresses (An address register
of 1 byte); the new system required much more than 256 addresses.  A
serial interface is operated at least in two modes:
  1.  An Address mode - During address mode the bits sent over the
       serial interface are address bits.  All members of the serial
       interface listen to the address.  At the end of the address
       mode typically one member is selected.
  2.  A Data mode - During data mode the bits sent over the serial
       interface are data bits.  Th...