ECU Bus Interface Codeword Switching for Non-Invasive Testing
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Solution Overview
Problem
Automotive ECU modules are difficult to test and debug without disassembly, as testing functions are only accessible via dedicated pins tied to supply and ground, limiting comprehensive debug and failure analysis in the field.
Innovation Solution
A system with a bus interface port, selection circuit, and initialization circuit that allows switching between different bus interface protocols, enabling non-invasive testing by detecting specific codewords to activate alternative test interfaces, such as the CAN interface for diagnostic access without disassembling the module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If dedicated test pins are used for component testing, then testing functionality is provided, but the pins are tied to supply and ground making them inaccessible for comprehensive debug and failure analysis
Solution Approach 1:
The bus interface port is designed to serve multiple functions: it operates as a standard communication interface during normal operation and can be configured as a test interface when a specific codeword is detected. This allows the same physical interface to provide both normal communication and comprehensive testing capabilities without requiring separate dedicated test pins.
Solution Approach 2:
The interface configuration is made dynamic by allowing the bus interface port to switch between different operational modes based on detected codewords. The selection circuit dynamically routes signals to different bus interface circuits (first for normal operation, second for testing) depending on the detected codeword, enabling flexible reconfiguration without physical changes.
2Measurement precision
If physical disassembly is performed for failure analysis, then comprehensive debugging is enabled, but time and expense are increased
Solution Approach 1:
The initialization circuit acts as an intermediary that detects the codeword and triggers the selection circuit to switch to the second bus interface circuit configured for testing. This intermediary mechanism enables test mode activation through the existing communication interface without requiring physical access to internal components, thereby providing comprehensive failure analysis capabilities while avoiding the time-consuming process of physical disassembly.
3Adaptability or versatility
If multiple bus interface circuits are implemented, then protocol switching capability is provided, but device complexity increases
Solution Approach 1:
The bus interface functionality is segmented into separate circuits: a first bus interface circuit for normal operation and a second bus interface circuit for testing. The selection circuit divides the single physical interface into two functional paths, allowing protocol switching between operational and test modes while keeping each individual circuit relatively simple and dedicated to its specific function.
Data Source
AI summary
In an embodiment, a system has a bus interface port, a selection circuit coupled to the bus interface port, a first bus interface circuit coupled to the selection circuit and a second bus interface circuit coupled to the selection circuit. The selection circuit is configured to select between the first bus interface circuit and the second bus interface circuit. The system also has an initialization circuit configured to detect a first codeword written to the bus interface port, and activate the second bus interface circuit if the first codeword is detected.