《SAE-AS-5643A-2006.pdf》由会员分享，可在线阅读，更多相关《SAE-AS-5643A-2006.pdf（40页珍藏版）》请在三一文库上搜索。
1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2006 SAE International All rights reserved. No part of this publication m
3、ay be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA)
4、 Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org AS5643 REV. A AEROSPACE STANDARD Issued 2004-12 Revised 2006-10 Superseding AS5643 IEEE-1394b Interface Requirements for Military and Aerospace Vehicle Applications RATIONALE In the original release of AS5643, the pr
5、iority values for word 3 of the ASM header are opposite what they should be. This occurred because of an error in the FC-AE-ASM draft document that was referenced. This limited scope revision to AS5643 references the recently-released FC-AE-ASM document and provides the necessary corrections to the
6、priority values for word 3 of the ASM header. TABLE OF CONTENTS 1. SCOPE3 1.1 Purpose.3 1.2 Application.3 1.3 Interpretation.3 1.4 Additions to the IEEE-1394, IEEE-1394a, and IEEE-1394b Standards.3 1.4.1 Use of Asynchronous Streams .3 1.4.2 A Fixed Frame Rate4 1.4.3 Synchronization Via Start of Fram
7、e Packets4 1.4.4 Static Assignment of Channel Numbers.4 1.4.5 Pre-Assignment of Bandwidth.4 1.4.6 Vertical Parity Check.4 1.4.7 Anonymous Subscriber Messaging4 2. DEFINITIONS AND APPLICABLE DOCUMENTS.4 2.1 Definitions .4 2.2 Government Documents.7 2.3 Non-Government Documents.7 2.4 Applicable Refere
8、nces7 3. IEEE-1394B REQUIREMENTS7 3.1 Data Bus Architecture and Operation.7 3.1.1 Basic Network Architecture.8 3.1.2 Basic Network Architecture With a Loop 9 3.1.3 Representative Triplex Network Architecture With Loops10 3.2 Data Bus Characteristics 11 3.2.1 Data Format11 3.2.2 Bit Ordering.11 3.2.3
9、 Transmission Method12 3.2.4 IEEE 1394 Packet Formats.12 3.2.5 IEEE-1394b Data Bus Initialization and Configuration .22 3.3 Node Operation.24 3.3.1 CC Node Operation 24 3.3.2 Remote Node Operation.33 SAE AS5643 Revision A - 2 - 3.3.3 Data Packet Types36 4. INTERFACE DEFINITIONS38 4.1 Destination Nod
10、e Channel Assignments38 APPENDIX A SLASH SHEET GUIDANCE.40 FIGURE 1 BASIC NETWORK WITH SINGLE CC COLORS, SHADING, AND OUTLINES COULD INDICATE DIFFERENT TYPES OF NODES ON THE BUSSES.8 FIGURE 2 BASIC NETWORK WITH SINGLE CC AND A LOOP COLORS, SHADING, AND OUTLINES COULD INDICATE DIFFERENT TYPES OF NODE
11、S ON THE BUSSES.9 FIGURE 3 REPRESENTATIVE TRIPLEX CC ARCHITECTURE10 FIGURE 4 BIT ORDERING11 FIGURE 5 ASYNCHRONOUS STREAM PACKET13 FIGURE 6 ASM HEADER 13 FIGURE 7 PAYLOAD DATA AREA15 FIGURE 8 PACKET TRAILER18 FIGURE 9 ASYNCHRONOUS TRANSACTION PACKET.20 FIGURE 10 ACKNOWLEDGE PACKET22 FIGURE 11 INITIAL
12、IZATION AND CONFIGURATION TIMING24 FIGURE 12 STOF PACKET.25 FIGURE 13 TEST MODE COMMAND WORD.29 FIGURE 14 TEST MODE READ COMMAND30 FIGURE 15 TEST MODE WRITE COMMAND 31 FIGURE 16 NORMAL BUS OPERATION34 FIGURE 17 FLOWCHART OF SYSTEM INTEGRITY MANAGEMENT36 FIGURE 18 ALLOCATING RESERVED BANDWIDTHS AND S
13、TOF TRANSMIT OFFSETS WITH MIXED DATA.37 TABLE 1 SUPPORTED DATA TYPES 11 TABLE 2 SPEED BITS.17 TABLE 3 AN EXAMPLE OF REMOTE NODE CHANNEL ASSIGNMENTS .38 SAE AS5643 Revision A - 3 - 1. SCOPE This SAE Aerospace Standard (AS) establishes the requirements for the use of IEEE-1394b as a data bus network i
14、n military and aerospace vehicles. It defines the concept of operations and information flow on the network. As discussed in 1.4, this specification contains extensions/restrictions to “off-the-shelf” IEEE-1394 standards, and assumes that the reader already has a working knowledge of IEEE-1394. This
15、 document is referred to as the “base” specification, containing the generic requirements that specify data bus characteristics, data formats and node operation. It is important to note that this specification is not stand-alone - several requirements provide only example implementations and delegat
16、e the actual implementation to be specified by the network architect/integrator for a particular vehicle application. This information is typically contained in a “network profile” slash sheet that is subservient to this base specification. In a similar manner, the electrical characteristics of the
17、bus media, as well as connector information is contained in a “physical layer” slash sheet, that also may be unique to a particular vehicle application. In summary, full understanding of this specification requires knowledge of IEEE-1394b standards and access to the physical layer slash sheets and t
18、he slash sheets and handbook for the target application. 1.1 Purpose The purpose of this document is to standardize an approach to using IEEE-1394 in safety-critical/mission-critical applications for military and aerospace vehicles. The information herein will be used to assist the design, fabricati
19、on, and maintenance of the nodes that interface via the vehicles network. This document is controlled and maintained by the SAE with technical support from Remote Node vendors. 1.2 Application The IEEE-1394 Network defined in this document provides a deterministic, rate based communication protocol
20、overlaid on the existing IEEE-1394 standard capabilities. 1.3 Interpretation The following interpretations shall be placed upon these words, unless stated otherwise, where they are used in this document. May: An allowed action. Shall: A mandatory requirement. Should: A recommended action. Will: A de
21、claration of intent. 1.4 Additions to the IEEE-1394, IEEE-1394a, and IEEE-1394b Standards Additions include the use of asynchronous stream packets, a fixed frame rate synchronized with a Start Of Frame packet, addition of a Vertical Parity Check, static assignment of channel numbers, pre-assignment
22、of bandwidth, and use of Anonymous Subscriber Messaging. 1.4.1 Use of Asynchronous Streams Asynchronous streams are used for most communication on the network. Asynchronous and isochronous packets are not required but may be utilized. Architectures and protocols discussed in the context of this docu
23、ment are based on asynchronous streams, unless it is otherwise mentioned. An example of using asynchronous packets would be to allow test equipment to read data from a Configuration ROM. An example of using isochronous packets would be for streaming video and/or audio. SAE AS5643 Revision A - 4 - 1.
24、4.2 A Fixed Frame Rate If isochronous packets are not utilized, there is no requirement for Cycle Start packets to be sent at the normal 125- microsecond rate. Instead, this implementation provides a fixed frame rate for synchronization of the network. If isochronous packets are utilized, it is nece
25、ssary to utilize the Cycle Master function so the 125-microsecond periodic cycle starts are available to isochronous sources that expect them. Figure 18 in 3.3.3.3 shows an example of interleaving isochronous packets and asynchronous stream packets. 1.4.3 Synchronization Via Start of Frame Packets A
26、 Start Of Frame (STOF) packet is transmitted by the Control Computer on each bus at a periodic (e.g. 100 Hertz) frame rate. This packet informs all nodes on the bus that a new frame has started. 1.4.4 Static Assignment of Channel Numbers Because asynchronous stream packets are, in reality, isochrono
27、us packets, the destination of the packet is identified by a channel number. Unlike standard 1394, the channel numbers for destination nodes are not assigned by an Isochronous Resource Manager (IRM). Instead, the channel numbers for each node on the bus are pre-assigned, are application specific, an
28、d will be defined as required by the architecture. 1.4.5 Pre-Assignment of Bandwidth The lack of an IRM requires that bandwidth be pre-assigned, also. Transmit and receive times for each node on the bus are assigned as offsets, in increments of 1 microsecond, from the start of each frame (STOF packe
29、t). The offsets for each node on the bus are application specific and will be defined as required by the architecture. 1.4.6 Vertical Parity Check Vertical Parity Checking (VPC) is performed on the data area of each packet as an adjunct to the Cyclic Redundancy Check (CRC) performed by the 1394 phys
30、ical layer devices. The VPC provides additional data integrity as the messages progress through the physical and software layers. 1.4.7 Anonymous Subscriber Messaging Anonymous Subscriber Messaging (ASM) is a protocol, in which, a Remote Node on the network can subscribe to each message that it requ
31、ires. The ASM software in the Remote Node will forward only the messages to which the Remote Node has subscribed. ASM is an upper level protocol tailored for the demands of highly modular embedded real time systems operating under a “data push” paradigm. ASM is designed to be independent of lower le
32、vel protocols and, as such, does not utilize the 1394 header to transport ASM-peculiar information. ASM is tailored to support deterministic, secure, low-latency communication between processors, sensors, instrumentation, and displays in mission-critical applications. It uses Message IDs to decouple
33、 the network traffic from physical addresses so application software can communicate without knowledge of network topology. 2. DEFINITIONS AND APPLICABLE DOCUMENTS 2.1 Definitions ASM HEADER: Anonymous Subscriber Messaging Header, the header that contains information relevant to the node transmittin
34、g the data and the communication status of that node. ASYNCHRONOUS: (1) pertaining to a transmission technique that does not require a common clock between the communicating devices. Timing signals are derived from special characters in the data stream itself. (2) not synchronous, not occurring or e
35、xisting at the same time or having the same period or phase. -,-,- SAE AS5643 Revision A - 5 - ASYNCHRONOUS STREAM PACKET: An isochronous packet that occurs in the fairness interval or asynchronous time frame. Data transmission is carried out in accordance with asynchronous arbitration rules; howeve
36、r, there is no acknowledge packet or response returned by the targeted node. ASYNCHRONOUS TRANSACTION: A transaction carried out in accordance with asynchronous arbitration rules. The transaction is always a request/response transaction and provides an acknowledgement of data delivery. BER: Bit Erro
37、r Rate is a parameter relating to the quality of a serial transmission system. BER is the percentage of bits having errors, relative to the total number of bits received in a transmission. BER is usually expressed as ten to a negative power. BIG ENDIAN: Describes a memory-addressing architecture in
38、which, within a given multi-byte numeric representation, the most significant byte has the lowest address (the word is stored big-end-first). Big-endian byte order is also sometimes called network order. BRANCH: A node physically connected to two or more nodes (i.e. two or more ports are connected).
39、 BUS: One of the 1394 trees connected to each CC Branch. BUS MANAGER: One node residing on the bus may be selected to provide serial bus services for the benefit of the community of all nodes residing on the bus. CC: Control Computer. The CC is the root node, Cycle Master (if used), and Bus Manager
40、for its respective data bus. CC-BRANCH: One set of redundant resources (e.g. a CC including all of its buses and Remote Node). CHANNEL/CHANNEL NUMBER: The means by which Isochronous and Asynchronous Stream packets are addressed. Data is transmitted onto the bus with a particular channel number. Node
41、s on the bus wishing to receive the data are configured to accept packets addressed with that channel number. CORBA: Common Object Request Broker Architecture, OMGs open, vendor-independent architecture and infrastructure that computer applications use to work together over networks. Using the stand
42、ard protocol IIOP, a CORBA-based program from any vendor, on almost any computer, operating system, programming language, and network, can interoperate with a CORBA-based program from the same or another vendor, on almost any other computer, operating system, programming language, and network. CRC:
43、Cyclic Redundancy Check a check summing algorithm generated and verified by the 1394 hardware. CYCLE MASTER: The node that generates the periodic (125s) cycle start packet. DATA PUMP: Internal equipment software parameters or memory values placed on the bus to support integration and test. FRAME: Th
44、e time interval between consecutive STOF messages (e.g. 10.0 milliseconds). ISOCHRONOUS: Uniform in time (i.e. having equal duration) and recurring at regular intervals. A form of data transmission that guarantees to provide a certain minimum data rate, as required for time-dependent data such as vi
45、deo or audio. Isochronous transmission transmits asynchronous data over a synchronous data link so that individual characters are only separated by a whole number of bit-length intervals. This is in contrast to asynchronous transmission, in which the characters may be separated by arbitrary interval
46、s, and with synchronous transmission. ISOCHRONOUS RESOURCE MANAGER: The node that maintains the channels available, bandwidth available, and bus manager ID registers. ISOCHRONOUS TRANSFER: A data transmission method that occurs uniformly in time and recurs at regular intervals (integer multiple of 1
47、25 s). -,-,- SAE AS5643 Revision A - 6 - LEAF: A node physically connected to only one other node (i.e. only one port is connected). LINK LAYER: The serial bus layer that defines the data transfer services. It also provides addressing, data checking, and data framing. LRC: Line Replaceable Component
48、. LRU: Line Replaceable Unit. MESSAGE: Unlike the classic definition of a message, this implementation limits a message to the amount of data that may encompass only one packet. NODE: An addressable device attached to the Serial Bus with at least the minimum set of control registers. Changing the co
49、ntrol registers on one node does not affect the state of control registers on another node. A node may have one or more ports. NODE ID: A 16-bit number (10-bit bus address/6-bit node address) that uniquely identifies a node. The node ID can change subsequent to a bus reset. PAYLOAD: The useful information or data contained within a message (e.g.