Overview
ISO 20794-5:2020 defines the application layer conformance test plan for implementations of ISO 20794-2:2020 (the CXPI application layer). CXPI (Clock eXtension Peripheral Interface) is an automotive low‑speed single‑wire in‑vehicle network used for simple devices (switches, sensors) and supports wake‑up/sleep, event‑triggered and polling communication methods. This part of the ISO 20794 series specifies how to verify that an implementation conforms to the application‑layer requirements through structured test cases, test conditions and system configuration rules.
Key topics and technical requirements
- Scope of conformance testing
- Conformance tests are specified for: concept of operation, network management, transfer management, and error management.
- Test architecture and setup
- Defines test system set‑up, test conditions, SUT/IUT requirements, and configuration parameters (including node modes such as Ready/Sleep and master/secondary clock master settings).
- Network management tests
- State transition verification, wake‑up and sleep request/notification handling, and multi‑clock master processing CTCs are covered. (See sections for state transitions, master/slave wake‑up triggers.)
- Transfer management tests
- Conformance test cases for event‑triggered and polling methods for master and slave nodes (e.g., 7.CTC_10.1 through 7.CTC_10.4), and behavior on invalid ReqId or unused response bits (7.CTC_10.5–10.7).
- Fault and error management
- Error detection/recovery, CXPI network error CTCs, SCT error handling and inter‑node error notifications are specified to validate robustness and application error reporting.
- SUT initialization and special configurations
- Default, sleep, power‑off, transmission prohibition and clock supply initialization procedures for repeatable test execution.
Practical applications - who uses this standard
- Automotive OEMs and Tier‑1 suppliers to validate ECUs and modules that implement the CXPI application layer.
- Conformance test labs and QA teams for formal verification and compliance testing.
- Firmware and communication protocol engineers to design CXPI‑compliant application behavior (wake/sleep, event vs polling).
- Diagnostic and system integrators to ensure predictable error reporting and network management across nodes.
Related standards
- ISO 20794-2:2020 - CXPI Application layer (normative reference)
- Other parts of the ISO 20794 series (physical, data link, transport/network layers)
- ISO/IEC 7498-1 - OSI Basic Reference Model
- ISO 14229 series - vehicle diagnostic communication
Keywords: ISO 20794-5, CXPI, conformance test plan, application layer, in‑vehicle network, clock extension peripheral interface, network management, transfer management, error management, automotive ECUs.