Browse Prior Art Database

Continuous Sequence Propagation Across an Asynchronous Boundary

IP.com Disclosure Number: IPCOM000120702D
Original Publication Date: 1991-May-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 44K

Publishing Venue

IBM

Related People

Harper, HM: AUTHOR [+3]

Abstract

Disclosed is a circuit/system (see the figure) whereby a deterministic continuous series of data characters may be transferred to a different data rate, without risking data backlog or requiring character 'stuffing' to compensate for the change in data rates.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 97% of the total text.

Continuous Sequence Propagation Across an Asynchronous Boundary

      Disclosed is a circuit/system (see the figure) whereby a
deterministic continuous series of data characters may be transferred
to a different data rate, without risking data backlog or requiring
character 'stuffing' to compensate for the change in data rates.

      Data entering the system 10 ('Data In' port 12 of the figure)
may be in one of two forms.  The data may consist of relatively
short, non-deterministic bursts of characters or the data may be in
the form of a continuously repeating character pattern.

      The short data bursts are transferred to the 'Data Out' port 14
using the Dual-Port Buffer 16 as shown in the figure.  The rate that
data enters the system (System Clock speed), inherently limits the
maximum length of a data burst.  For this reason, long periods of
data transfer cannot be handled by the Dual-Port Buffer 16.

      When data in the form of a continuously repeating character
pattern is recognized at the system input 12, the data is effectively
transferred to the system output 14 by using a control byte, shown in
the figure as the Sequence Identifier 18.  Using this control byte,
the regeneration logic 20 generates the same sequence on the output
side for as long as the control byte remains active.  Thus, the
pattern detected at the input 12 is sustained at the output 14,
without a one-to-one correspondence of inbound data characters to
outbound data charac...