ISO 20794-2-2020 PDF

Full title and description

Road vehicles — Clock extension peripheral interface (CXPI) — Part 2: Application layer. This international standard specifies the CXPI application-layer protocol used in automotive on-board networks, covering application message structure, service interface and parameters, transfer management and fault handling.

Abstract

This document describes the CXPI application layer including application measurement and control data management, message transfer and fault management. It defines message structure and communication methods, optional network management, measurement and control data formats, error handling and the service interface (including service interface parameters).

General information

• Status: Published (International Standard, confirmed).
• Publication date: February 2020 (Edition 1: 2020-02).
• Publisher: ISO (International Organization for Standardization).
• ICS / categories: 43.040.15 (Car informatics; on-board computer systems).
• Edition / version: Edition 1 (2020-02).
• Number of pages: 37 pages.

Core bibliographic and status details as published by ISO.

Scope

Specifies the application layer protocol for CXPI (Clock eXtension Peripheral Interface) in road vehicles: message structure and formats, communication methods, (optional) network management, measurement and control data handling, error handling and the service interface and its parameters. The scope is limited to the application-layer services and interfaces that sit above the transport/network and data-link/physical layers defined in other parts of the ISO 20794 series.

Key topics and requirements

• Definition of application message structure and encoding rules.
• Application-level communication methods and transfer management.
• Measurement and control data management (formats and semantics).
• Optional network management functions relevant to the application layer.
• Error detection, reporting and fault management at application level.
• Service interface specification and parameters exposed to higher-layer applications.

These topics are drawn from the standard's abstract and clause structure.

Typical use and users

Used by automotive OEM system architects, in-vehicle network and ECU software designers, tier‑1 suppliers, semiconductor and transceiver IC vendors implementing CXPI stacks, test laboratories and conformance test tool developers, and technical authors preparing integration and diagnostic documentation. It is applied where CXPI is selected as a low-cost peripheral network (for sensors, actuators and body electronics) in vehicle architectures.

Related standards

ISO 20794 is a multipart series defining CXPI across OSI layers and conformance tests. Relevant parts include: ISO 20794-3:2020 — Transport and network layer; ISO 20794-4:2020 — Data link layer and physical layer; ISO 20794-5:2020 — Application layer conformance test plan; ISO 20794-6:2020 — Transport and network layer conformance test plan; ISO 20794-7:2020 — Data link and physical layer conformance test plan. These companion parts specify lower-layer protocols and the conformance test plans against which implementations of ISO 20794-2 are validated.

Keywords

CXPI, Clock extension peripheral interface, application layer, automotive, in-vehicle network, ECU, message structure, service interface, conformance test, ISO 20794.

FAQ

Q: What is this standard?

A: ISO 20794-2:2020 is the part of the ISO 20794 series that defines the CXPI application-layer protocol for road vehicles, detailing message formats, service interfaces and application-level error handling.

Q: What does it cover?

A: It covers application message structure, communication and transfer methods, measurement and control data management, optional network management at the application level, error handling and the definition of the service interface and its parameters used by higher-layer functions.

Q: Who typically uses it?

A: Automotive OEMs, ECU and embedded software engineers, semiconductor and transceiver IC vendors, tier‑1 suppliers, test houses and integrators implementing or verifying CXPI-based in-vehicle networks.

Q: Is it current or superseded?

A: As published it is Edition 1 (February 2020). ISO indicates the standard is published and maintained under the ISO review cycle (the 2020 editions of the 20794 parts have been subject to ISO confirmation/review). Users should check ISO or national standards bodies for the absolute latest status before procurement or compliance activities.

Q: Is it part of a series?

A: Yes — ISO 20794 is a multipart standard (parts 2–7 in the 2020 series) covering application, transport/network, data link/physical layers and associated conformance test plans for CXPI. Implementers normally use multiple parts together (e.g., parts 2, 3, 4 and the relevant conformance test parts).

Q: What are the key keywords?

A: CXPI, application layer, message structure, service interface, automotive network, in-vehicle communication, conformance test, ISO 20794.