SAE AS 5652A-2018 10 Megabit sec Network Configuration Digital Time Division Command Response Multiplex Data Bus.pdf

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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

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3、ublication may 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: +1 724-776-497

4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/standards.sae.org/AS5652A AEROSPACE STANDARD AS5652 REV. A Issued 2005-12 Reaffirmed 2013-04 Revised 2018-01 Supe

5、rseding AS5652 10 Megabit/sec Network Configuration Digital Time Division Command/Response Multiplex Data Bus RATIONALE Revision A corrects Figure numbers in the captions. There were no other changes to the content. FOREWORD This standard was developed in conjunction with the Miniature Munitions Int

6、erface Standard in order to support a distributed RT point-to-point network configuration. SAE INTERNATIONAL AS5652A Page 2 of 28 TABLE OF CONTENTS 1. SCOPE 3 1.1 Purpose . 3 1.2 Field of Application 3 2. REFERENCES 3 2.1 Applicable Documents 3 2.1.1 SAE Publications . 4 2.1.2 TIA Publications 4 2.1

7、.3 U.S. Government Publications 4 2.2 Definitions . 4 2.3 Acronymns and Abbreviations 6 3. GENERAL REQUIREMENTS . 7 3.1 Test and Operating Requirements 7 3.2 Data Bus Operation . 7 3.3 Characteristics 8 3.3.1 Data Form . 8 3.3.2 Bit Priority 8 3.3.3 Transmission Method 8 3.4 Terminal Operation . 18

8、3.4.1 Common Operation . 18 3.4.2 Bus Controller Operation. 19 3.4.3 Remote Terminal . 19 3.4.4 Monitor Operation . 20 3.5 Hardware Characteristics 20 3.5.1 Data Bus Characteristics. 20 3.5.2 Terminal Characteristics . 21 4. OPERATIONAL MODES AND GUIDELINES . 25 4.1 Bus Controller and Logical Hub 25

9、 4.1.1 Logical Hub . 25 4.2 Multiplex Selection Criteria . 27 4.3 Line Connections 27 4.4 Required Mode Codes 28 4.5 Use of Broadcast Option . 28 5. NOTES 28 5.1 Revision Indicator 28 Figure 1 Data bus network configuration 3 Figure 2 BC logical hubstar architecture . 5 Figure 3 Data bus with subsys

10、tems and monitors 7 Figure 4 Data encoding . 9 Figure 5 Word formats . 9 Figure 6A Command and status sync waveform . 10 Figure 6B Data word sync . 14 Figure 7 Information transfer formats 17 Figure 8 Broadcast information transfer formats . 17 Figure 9 Intermessage gap and RT response time . 18 Fig

11、ure 10 Example implementation of BC to RT interface line cable 21 Figure 11 Terminal I/O characteristics 22 Figure 12 Output waveform . 22 Figure 13 Location “A” on a BC to RT interface example . 24 Figure 14 Three operating modes of logic level hub . 26 Table 1 Assigned mode codes . 13 Table 2 Crit

12、eria for acceptance or rejection of a terminal for the noise rejection test total words received by the terminal (in multiples of 107) 24 SAE INTERNATIONAL AS5652A Page 3 of 28 1. SCOPE This SAE Aerospace Standard (AS) contains requirements for a digital time division command/response multiplex data

13、 bus, for use in systems integration that is functionally similar to MIL-STD-1553B with Notice 2 but with a star topology and some deleted functionality. Even with the use of this document, differences may exist between multiplex data buses in different system applications due to particular applicat

14、ion requirements and the options allowed in this document. The system designer must recognize this fact and design the multiplex bus controller (BC) hardware and software to accommodate such differences. These designer selected options must exist to allow the necessary flexibility in the design of s

15、pecific multiplex systems in order to provide for the control mechanism, architectural redundancy, degradation concept, and traffic patterns peculiar to the specific application requirements. 1.1 Purpose This document establishes requirements for digital, command/response, time division multiplexing

16、 (Data bus) techniques. It encompasses the data bus line and its interface electronics illustrated on Figure 1, and also defines the concept of operation and information flow on the multiplex data bus and the electrical and functional formats to be employed. Figure 1 - Data bus network configuration

17、 1.2 Field of Application When invoked in a specification or statement of work, these requirements shall apply to the multiplex data bus and associated equipment which is developed either alone or as a portion of a Miniature Mission Store weapon system or subsystem development. The contractor is res

18、ponsible for invoking all the applicable requirements of this standard on any and all subcontractors he may employ. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The app

19、licable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and re

20、gulations unless a specific exemption has been obtained. Bus ControllerRTRTUp to 31 Remote TerminalAddresses 0 - 30SAE INTERNATIONAL AS5652A Page 4 of 28 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Cana

21、da) or +1 724-776-4970 (outside USA), www.sae.org. ARP4242 Electromagnetic Compatibility Control Requirements Systems 2.1.2 TIA Publications Available from TIA, Standards and Technology Department, 2500 Wilson Boulevard, Arlington, VA 22201, www.tiaonline.org/standards/. TIA/EIA-485-A 21 Electrical

22、Characteristics of Generators and Receivers for (ANSI/TIA/EIA-485-A-98) Use in Balanced Multipoint Systems 2.1.3 U.S. Government Publications Copies of these documents are available online at http:/quicksearch.dla.mil. MIL-STD-1553B Digital Time Division Command/Response Multiplex Data Bus MIL-STD-4

23、64 Electromagnetic Environmental Effects, Requirements for Systems 2.2 Definitions ASYNCHRONOUS OPERATION: For the purpose of this standard, asynchronous operation is the use of an independent clock source in each terminal for message transmission. Decoding is achieved in receiving terminals using c

24、lock information derived from the message. BIT RATE: The number of bits transmitted per second. BIT: Contraction of binary digit: may be either zero or one. In information theory a binary digit is equal to one binary decision or the designation of one of two possible values or states of anything use

25、d to store or convey information. BROADCAST: Operation of a data bus system such that information transmitted by the bus is addressed to more than one of the remote terminals connected to the data bus. Bus Controller (BC): The terminal assigned the task of initiating information transfers on the dat

26、a bus. BUS MONITOR (BM): The terminal assigned the task of listening to Logical Hub activity with ability to extract selected information, to be used at a later time. Bus Monitor may be stand alone or incorporated into another terminal. COMMAND/RESPONSE: Operation of a data bus system such that remo

27、te terminals receive and transmit data only when commanded to do so by the bus controller. COMPOSITE BUS MONITOR (cBM): The cBM provides a time correlated transmission of all activity entering and departing the Logical Hub, including all BC and RT valid, invalid, legal and illegal words. DATA BUS: W

28、henever a data bus or bus is referred to in this document it shall imply all the hardware including twisted shielded pair cables, required to provide a single data path between the bus controller and each associated remote terminal resulting in a Star Topology, as seen in Figure 2. SAE INTERNATIONAL

29、 AS5652A Page 5 of 28 Figure 2 - BC logical hub - star architecture HALF DUPLEX: Operation of a data transfer system in either direction over a single line, but not in both directions on that line simultaneously. LOGICAL LEVEL HUB: In this document, the Logical Level Hub or just Logical Hub is a set

30、 of Hardware and/or software providing logical communications from the BC to and from each implemented RT, authorized by command word RT address bits, thru the RS-485 transceivers. The hub architecture is known as an Active Star Configuration; where the active function limits responses from the Remo

31、te Terminals so that the BC receives communications from only one RT at a time. The Logical Hub also supplies a composite Bus Monitoring traffic line out, to allow monitoring of all activity within the Logical Hub. See Figures 2 and 3. MESSAGE: A single message is the transmission of a command word,

32、 status word, and data words if they are specified. MODE CODE: A means by which the bus controller can communicate with the multiplex bus related hardware, in order to assist in the management of information flow. MULTIPLEX DATA BUS: A communications pathway, based on a physical media, where Time Di

33、vision Multiplexing is employed in order to manage the transfer of information to and from terminals located across the physical media. PULSE CODE MODULATION (PCM): The form of modulation in which the modulation signal is sampled, quantized, and coded so that each element of information consists of

34、different types or numbers of pulses and spaces. REMOTE TERMINAL (RT): All terminals not operating as the bus controller or as a bus monitor. RT LINK SHUTDOWN: The shutdown function contained within the BC/Logical Hub for inhibiting all transmissions to an RT link. SUBSYSTEM: The device or functiona

35、l unit receiving data transfer service from the data bus. TERMINAL: The electronic module necessary to interface the data bus with the subsystem and the subsystem with the data bus. Terminals may exist as separate line replaceable units (LRUs) or be contained within the elements of the subsystem. TE

36、RMINAL MONITOR (TM): The terminal assigned the task of listening to RT line traffic with ability to extract selected information, to be used at a later time. Terminal Monitor may be stand alone or incorporated into another terminal. BMRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTRTBCL

37、OGICAL HUBSAE INTERNATIONAL AS5652A Page 6 of 28 TIME DIVISION MULTIPLEXING (TDM): The transmission of information from several signal sources through one communication system with different signal samples staggered in time to form a composite pulse train. WORD: In this document a word is a sequence

38、 of 16 bits plus sync and parity. There are three types of words: command, status and data. 2.3 Acronymns and Abbreviations AIR Aerospace Information Report ARP Aerospace Recommended Practice BC to RT Bus controller to remote terminal transfer BC Bus controller BIT Built-in-test BM Bus monitor CS Cl

39、ear Status dB Decibels DC Direct current EMC Electromagnetic compatibility ft Feet kHz Kilohertz LRU Line replaceable unit LSB Least significant bit MC Mode code MHz Megahertz MIL-STD Military Standard MSB Most significant bit ms Milliseconds mV Millivolts ns Nanoseconds PCM Pulse code modulation P

40、Parity RMS Root-mean-square RT to BC Remote terminal to bus controller transfer SAE INTERNATIONAL AS5652A Page 7 of 28 RT Remote terminal T/R Transmit/receive TBD To be determined TDM Time division multiplexing TF Terminal flag V Volt Zo Nominal characteristic impedance 3. GENERAL REQUIREMENTS 3.1 T

41、est and Operating Requirements All requirements as specified herein shall be valid over the environmental conditions, which the multiplex data bus system shall be required to operate. 3.2 Data Bus Operation The multiplex data bus system in its most elemental configuration shall be as shown on Figure

42、 1, consisting of a Bus Controller with 1 to 31 individual lines, having one line to each respective Remote Terminal. An example of the data bus including subsystems and bus monitors can be seen in Figure 3. The multiplex data bus system shall function asynchronously in a command/response mode, and

43、transmission shall occur in a half-duplex manner. Sole control of information transmission on the bus shall reside with the Bus Controller, which shall initiate all transmissions. The information flow on the data bus shall be comprised of messages, formed, by three types of words (command, data, and

44、 status) as defined in 3.3.3.5. Figure 3 - Data bus with subsystems and monitors Bus ControllerLogical Level HubSubsystemSubsystemwith embeddedRemote TerminalSubsystem(s)Remote TerminalBus MonitortoHub TrafficSubsystemwith embeddedRemote TerminalTerminal MonitortoRT Line TrafficSAE INTERNATIONAL AS5

45、652A Page 8 of 28 3.3 Characteristics 3.3.1 Data Form Digital data may be transmitted in any desired form, provided that the chosen form shall be compatible with the message and word formats defined in this standard. Any unused bit positions in a word shall be transmitted as logic zeros. 3.3.2 Bit P

46、riority The most significant bit (MSB) shall be transmitted first with the less significant bits following in descending order of value in the data word. The number of bits required to define a quantity shall be consistent with the resolution or accuracy required. In the event that multiple precisio

47、n quantities (information accuracy or resolution requiring more than 16 bits) are transmitted, the most significant bits shall be transmitted first, followed by the word(s) containing the lesser significant bits in numerical descending order. Bit packing of multiple quantities in a single data word

48、is permitted. 3.3.3 Transmission Method 3.3.3.1 Modulation The signal shall be transferred over the data bus in serial digital pulse code modulation (PCM) form. 3.3.3.2 Data Code The data code shall be Manchester II bi-phase level. A logic one shall be transmitted as a bipolar coded signal 1/0 (i.e.

49、, a positive pulse followed by a negative pulse). A logic zero shall be a bipolar coded signal 0/1 (i.e., a negative pulse followed by a positive pulse). A transition through zero occurs at the midpoint of each bit time (see Figure 4). 3.3.3.3 Transmission Bit Rate The transmission bit rate on the bus shall be 10 megabit per second with a combined accuracy and long-term stability of 0.1% (i.e., 10000 Hz). The short-term stability (i.