IEEE Std 1394b
™
-2002
(Amendment to IEEE Std 1394
™
-1995)
IEEE Standards
1394b
TM
IEEE Standard for a High-Performance
Serial Bus—Amendment 2
Published by
The Institute of Electrical and Electronics Engineers, Inc.
3 Park Avenue, New York, NY 10016-5997, USA
14 December 2002
IEEE Computer Society
Sponsored by the
Microprocessor and Microcomputer Standards Committee
IEEE Standards
Print: SH94986
PDF: SS94986
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IEEE Std 1394b
™
-2002
(Amendment to
IEEE Std 1394
™
-1995)
IEEE Standard for a High-Performance
Serial Bus—Amendment 2
Sponsor
Microprocessor and Microcomputer Standards Committee
of the
IEEE Computer Society
Approved 1 August 2002
American National Standards Institute
Approved 20 March 2002
IEEE-SA Standards Board
Abstract:
Supplemental information for a high-speed serial bus that integrates well with most
IEEE standard 32-bit and 64-bit parallel buses is specified. It is intended to extend the usefulness
of a low-cost interconnect between external peripherals. This standard follows the IEEE Std
1212
™
-2001 Command and Status Register (CSR) architecture.
Keywords:
bus, computers, high-speed serial bus, interconnect
Recognized as an
American National Standard (ANSI)
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iii
Copyright © 2002 IEEE. All rights reserved.
Introduction
(This introduction is not part of IEEE Std 1394b-2002, IEEE Standard for a High-Performance Serial Bus—Amendment
2.)
Work on IEEE Std 1394b-2002 was begun in the winter of 1997 at a meeting of the 1394TA in Eind-
hoven. By that time, it had become evident that
IEEE Std 1394-1995
was going to be widely deployed and
that many devices, especially new, digital consumer products, were going to have IEEE 1394 as the pri-
mary external interface. In the first meetings of this group, considerable sentiment existed for broaden-
ing the number and types of devices that would be able to use the IEEE 1394 interface and thereby
making the interface more valuable to the end user. While attempting to broaden the scope of the
IEEE 1394 interface, two barriers were discovered that made wider deployment difficult: the interface
was constrained to operate over a fairly short distance and it could not handle higher data rates.
After some preliminary investigations, the group concluded that these problems were best solved by a
change in coding. While the data-strobe (DS) coding used in IEEE Std 1394-1995 was a simple, self-
clocking scheme, the fact that it is not dc balanced made it impractical to use over longer distances. Fur-
thermore, accumulated skew on a long-distance connection makes it hard to maintain the timing rela-
tionships between the data and the strobe lines, especially at higher data rates. The group rapidly
converged on the notion of using a variant of 8B/10B coding developed by IBM for the longer distances
and higher speeds defined in IEEE Std 1394b-2002. Where the connection between devices was copper
cable of 5 m or less, some or all of the ports on a new physical layer (PHY) developed to support this
standard could be able to signal using either DS or the new signaling scheme (dubbed
Beta mode
). These
bilingual
ports would be able to select the optimum signaling method for the connection and thereby be
able to fully interoperate with existing devices that are compliant with IEEE Std 1394-1995 and IEEE
Std 1394a
™
-2000.
The new signalling system provided a route to solving a second major problem, i.e., the lack of scalabil-
ity of the IEEE 1394 arbitration scheme as signaling rates are increased. The use of 8B/10B encoding
allows the transmission of data to be overlapped with the transmission of arbitration signals in the
reverse direction. The use of overlapped arbitration is extended by one level of pipelining, with the result
that in a purely IEEE 1394b bus the need for arbitration gaps is entirely eliminated. In fact, on a bus
with all connections operating in Beta mode, the setting of gap count has no utility as the bus is com-
pletely self-timed.
As work progressed, the group became interested in applying the new coding scheme to a large variety
of interconnect media including plastic optical fiber (POF), glass optical fiber (GOF), and Category 5
(CAT-5) unshielded twisted pair (UTP). This goal greatly expanded the scope of the work and made it
necessary to divide the IEEE P1394b Working Group into various task groups. The leaders of these
groups were largely responsible for the development of IEEE Std 1394b-2002. Because of the length of
the project, some of the task groups had more than one leader. The task groups, their leaders, and their
contributions are as follows:
—
Glass Fiber
. Colin Whitby-Strevens. This group adopted the work from the Fibre Channel specifi-
cation for use in IEEE Std 1394b-2002. The jitter work done in this group was adapted for use in
all the media.
—
Plastic Fiber
. Taka Fujimori, Shuntaro Yamazaki, Victoria K. M. Teng, and Kazuki Nakamura.
This group actually developed a standard around a single connector that allowed interoperation
and intermating of both plastic fiber or large-diameter hard polymer clad fiber (HPCF). This con-
nector can be used at a speed of S100.
—
UTP5
. Colin Whitby-Strevens and Alistair Coles. This group built on work done in the 100BaseT
standard with extensive changes to simplify the coding and transmission over CAT-5 UTP.
