1、 Reference number ISO 17356-4:2005(E) ISO 2005INTERNATIONAL STANDARD ISO 17356-4 First edition 2005-11-01 Road vehicles Open interface for embedded automotive applications Part 4: OSEK/VDX Communication (COM) Vhicules routiers Interface ouverte pour applications automobiles embarques Partie 4: Commu
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5、ecretariat at the address given below. ISO 2005 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the
6、 address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2005 All rights reservedISO 17356-4:2005(E) ISO 2005 All rig
7、hts reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Interaction Layer. 1 3.1 Overview 1 3.2 Message reception 4 3.3 Message transmission . 7 3.4 Byte order conversion and message interpretation . 14 3.5 Deadline monitoring . 16 3.6 Notification 21 3.7 C
8、ommunication system management 22 3.8 Functional model of the Interaction Layer .26 3.9 Interfaces . 28 4 Minimum requirements of lower communication layers 43 5 Conformance Classes 44 Annex A (informative) Use of ISO 17356-4 (COM) with an OS not conforming to ISO 17356-3 46 Annex B (informative) Ap
9、plication notes. 47 Annex C (informative) Callouts .54 ISO 17356-4:2005(E) iv ISO 2005 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is nor
10、mally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in
11、the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepar
12、e International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that som
13、e of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 17356-4 was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical and electronic equipment. ISO 17356 consist
14、s of the following parts, under the general title Road vehicles Open interface for embedded automotive applications: Part 1: General structure and terms, definitions and abbreviated terms Part 2: OSEK/VDX specifications for binding OS, COM and NM Part 3: OSEK/VDX Operating System (OS) Part 4: OSEK/V
15、DX Communication (COM) Part 5: OSEK/VDX Network Management (NM) Part 6: OSEK/VDX Implementation Language (OIL) ISO 17356-4:2005(E) ISO 2005 All rights reserved v Introduction This part of ISO 17356 specifies a uniform communication environment for automotive control unit application software. It inc
16、reases the portability of application software modules by defining common software communication interfaces and behaviour for internal communication communication within an electronic control unit (ECU) and external communication (communication between networked vehicle nodes), which is independent
17、of the communication protocol used. This part of ISO 17356 describes the behaviour within one ECU. It assumes that the communication environment described in this part of ISO 17356 is used together with an operating system that conforms to ISO 17356-3. For information on how to run the communication
18、 environment described in this part of ISO 17356 on operating systems that do not conform to ISO 17356-3, refer to Annex A. Requirements The following main requirements are fulfilled by this part of ISO 17356: General communication functionality This part of ISO 17356 offers services to transfer dat
19、a between tasks and/or interrupt service routines. Different tasks may reside in one and the same ECU (internal communication) or in different ECUs (external communication). Access to ISO 17356-4 services is only possible via the specified Application Program Interface (API). Portability, reusabilit
20、y and interoperability of application software It is the aim of this part of ISO 17356 to support the portability, reusability and interoperability of application software. The API hides the differences between internal and external communication as well as different communication protocols, bus sys
21、tems and networks. Scalability This part of ISO 17356 ensures that an ISO 17356-4 implementation can run on many hardware platforms. The implementation requires only a minimum of hardware resources, therefore different levels of functionality (conformance classes) are provided. Support for ISO 17356
22、-5 (Network Management-NM): Services to support Indirect NM are provided. Direct NM has no requirements of this part of ISO 17356. Communication concept Figure 1 shows the conceptual model of this part of ISO 17356 and its positioning within the architecture defined by ISO 17356. This model is prese
23、nted for better understanding, but does not imply a particular implementation of this part of ISO 17356. ISO 17356-4:2005(E) vi ISO 2005 All rights reservedFigure 1 COMs layer model In this model, the scope of this part of ISO 17356 partly or entirely covers the following layers: Interaction Layer T
24、he Interaction Layer (IL) provides the ISO 17356-4 API which contains services for the transfer (send and receive operations) of messages. For external communication it uses services provided by the lower layers, whereas internal communication is handled entirely by the IL. Network Layer The Network
25、 Layer handles depending on the communication protocol used message segmentation/recombination and acknowledgement. It provides flow control mechanisms to enable the interfacing of communication peers featuring different levels of performance and capabilities. The Network Layer uses services provide
26、d by the Data Link Layer. This part of ISO 17356 does not specify the Network Layer; it merely defines minimum requirements for the Network Layer to support all features of the IL. Data Link Layer The Data Link Layer provides the upper layers with services for the unacknowledged transfer of individu
27、al data packets (frames) over a network. Additionally, it provides services for the NM. This part of ISO 17356 does not specify the Data Link Layer; it merely defines minimum requirements for the Data Link Layer to support all features of the IL. ISO 17356-4:2005(E) ISO 2005 All rights reserved vii
28、Structure of this document In the following text, the specification chapters are described briefly. Clauses 1 to 5 are normative, the appendices are descriptive. Clause 1: Scope This clause describes the motivation and requirements for this part of ISO 17356, the conceptual model used and the struct
29、ure of the document. Clause 2: Normative references Clause 3: Interaction Layer This clause describes the functionality of the IL of the ISO 17356-4 model and defines its API. Clause 4: Minimum requirements of lower communication layers This clause lists the requirements imposed by this part of ISO
30、17356 on the lower communication layers (Network Layer and Data Link Layer) to support all features of the IL. Clause 5: Conformance Classes This clause specifies the Communication Conformance Classes, which allow the adaptation of the feature content of ISO 17356-4 implementations to the target sys
31、tems requirements. Annex A: Use of this part of ISO 17356 (Com) with an OS not conforming to ISO 17356-3 Annex A gives hints on how to run this part of ISO 17356 on operating systems that do not conform to ISO 17356-3. Annex B: Application notes Annex B provides information on how to meet specific a
32、pplication requirements with the given ISO 17356-4 model. Annex C: Callouts Annex C supplies application examples for callouts. INTERNATIONAL STANDARD ISO 17356-4:2005(E) ISO 2005 All rights reserved 1Road vehicles Open interface for embedded automotive applications Part 4: OSEK/VDX Communication (C
33、OM) 1 Scope This part of ISO 17356-4 (COM) specifies a uniform communication environment for automatic control unit application software. It increases the portability of application software modules by defining common software communication interfaces and behaviours for internal communication (commu
34、nication within an ECU) and external communication (communication between networked vehicle nodes), which is independent of the used communication protocol. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only th
35、e edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 17356-2, Road vehicles Open interface for embedded automotive applications Part 2 OSEK/VDX specifications for binding OS, COM and NM ISO 17356-3, Road vehicles Open
36、interface for embedded automotive applications Part 3 OSEK/VDX Operating System (OS) ISO 17356-5, Road vehicles Open interface for embedded automotive applications Part 5 OSEK/VDX Network Management (NM) ISO 17356-6, Road vehicles Open interface for embedded automotive applications Part 6 OSEK/VDX I
37、mplementation Language (OIL) 3 Interaction Layer 3.1 Overview 3.1.1 Presentation The communication in this part of ISO 17356 is based on messages 1) . A message contains application- specific data. Messages and message properties are configured statically via OIL (ISO 17356-6). The content and usage
38、 of messages is not relevant to this part of ISO 17356. Messages with a length of zero (see zero- length messages, Annex B) are allowed. 1) Messages are often called signals. Thus, COM offers a signal-based interface. ISO 17356-4:2005(E) 2 ISO 2005 All rights reservedIn the case of internal communic
39、ation, the Interaction Layer (IL) makes the message data immediately available to the receiver (see Figure 2). In the case of external communication, the IL packs one or more messages into assigned Interaction Layer Protocol Data Units (I-PDU) and passes them to the underlying layer. The functionali
40、ty of internal communication is a subset of the functionality of external communication. Internal-external communication occurs when the same message is sent internally as well as externally. Administration of messages is done in the IL based on message objects. Message objects exist on the sending
41、side (sending message object) and on the receiving side (receiving message object). Figure 2 Simplified model for message transmission and reception in ISO 17356-4 The data that is communicated between the IL and the underlying layer is organized into I-PDUs which contain one or more messages (see F
42、igure 2). A message shall occupy contiguous bits within an I-PDU and shall not be split across I-PDUs. Within an I-PDU messages are bit-aligned. The size of a message is specified in bits. The byte order (endianess) in a CPU can differ from the network representation or from other CPUs on the networ
43、k. Therefore, to provide interoperability across the network, the IL provides a conversion from the network representation to the local CPU representation and vice versa, which is statically configured on a per- message basis. The IL offers an Application Program Interface (API) to handle messages.
44、The API provides services for initialization, data transfer and communication management. Services transmitting messages over network are non-blocking. This implies, for example, that a service that sends a message is unable to return a final transmission status because the transfer to the network i
45、s still in progress. This part of ISO 17356 provides notification mechanisms for an application to determine the status of a transmission or reception. The functionality of the IL can be extended by callouts. (3.8 contains a description of where callouts can be inserted.) ISO 17356-4:2005(E) ISO 200
46、5 All rights reserved 3 3.1.2 Communication concept Senders and receivers of messages are either tasks or interrupt service routines (ISRs) in an OS. Messages are sent to sending message objects and received from receiving message objects. Message objects are identified using message identifiers. Me
47、ssage identifiers are assigned to message objects at system generation. This part of ISO 17356 supports communication from “m” senders to “n” receivers (m:n communication). Zero or more senders can send messages to the same sending message object. Sending message objects are configured to store mess
48、ages in zero or more receiving message objects for internal communication and in zero or one I-PDUs for external communication. One or more sending message objects can be configured to store messages in the same I-PDU for external communication. An I-PDU can be received by zero or more CPUs. In each
49、 CPU which receives the I-PDU, each message contained in the I-PDU is stored in zero or more receiving message objects. Zero or more receivers can receive messages from a receiving message object (see Annex B for additional information). A receiving message object receives messages from either exactly one sending message object (internal communication) or exactly one I-PDU, or it receives no messages at all. A receiving message object can be defined as either queued or unqueued. While a message
