FlexRay Controller Loop-Back Testing via Channel Segmentation
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Solution Overview
Problem
Conventional FlexRay communication controllers lack comprehensive loop-back functionality for power-on checking and monitoring, as they cannot transmit data on one channel and receive it on the other, limiting the extent of path coverage and requiring additional controllers for full functional testing.
Innovation Solution
A communication controller that operates in two modes: a normal mode where data is not decodable between channels, and a test mode where the same cyclic redundancy code initialization values are used for both channels, enabling loop-back functionality without the need for a second communication controller, allowing for channel supervision and monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a second communication controller is used for monitoring and loop-back testing, then test coverage and functional monitoring capability are improved, but device complexity and hardware requirements increase
Solution Approach 1:
The patent merges the monitoring function and loop-back testing capability into the existing communication controller by utilizing the second communication channel. The controller can transmit data on the first channel and receive it on the second channel, creating an internal loop-back path without requiring a separate monitoring controller. This consolidation maintains comprehensive test coverage while reducing hardware complexity.
Solution Approach 2:
The communication controller is designed to perform multiple functions: normal data communication on both channels, self-monitoring of the first channel via the second channel, and loop-back testing. By making the controller universal and capable of handling both communication and monitoring tasks, the patent eliminates the need for a dedicated second controller while maintaining full functional coverage.
2Ease of manufacture
If loop-back functionality is implemented using existing FlexRay controllers, then partial testing capability is achieved, but the extent of path coverage is limited and cannot cover the connection to the physical interface converter
Solution Approach 1:
The patent segments the communication path into distinct segments that can be individually tested. By using the second communication channel as a separate test path, the system can isolate and test specific segments including the connection to the physical interface converter. The loop-back mechanism allows testing of the transmit path, receive path, and intermediate connections as separate testable segments.
Solution Approach 2:
The second communication channel acts as an intermediary medium for loop-back testing. Instead of directly connecting transmit and receive paths within the same channel, the data is transmitted through the second channel which serves as a mediator, enabling comprehensive testing of the entire signal path including connections to the physical interface converter that were previously inaccessible.
3Adaptability or versatility
If a communication controller transmits data on one channel and attempts to receive it on the other channel, then loop-back functionality is achieved, but FlexRay half-duplex protocol restrictions prevent this operation
Solution Approach 1:
The communication controller dynamically switches between different operational modes for each channel. During normal operation, both channels follow standard FlexRay half-duplex protocols. During loop-back testing, the controller dynamically reconfigures the second channel to receive and decode transmissions from the first channel, enabling adaptability without permanent protocol violations or hardware modifications.
Solution Approach 2:
The patent utilizes parameter changes in the cyclic redundancy code (CRC) initialization values to enable mode switching. By changing the CRC parameters based on the operational mode (normal communication vs. loop-back testing), the controller can seamlessly transition between functions while maintaining protocol compliance. The second channel can be configured with appropriate CRC parameters to decode transmissions from the first channel during testing.
Data Source
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AI summary
A communication controller (25) is described. The communication controller can exchange data on first and second communications channels (A, B). In a first mode, data transmitted on the first communication channel cannot be decoded on the second communication channel. In a second mode, data transmitted on the first communication channel is decodable on the second communication channel so as to provide loop back functionality.