Microcomputer Nonvolatile Memory Backup for OTA Updates
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Solution Overview
Problem
The existing methods for updating control software in electronic control units (ECUs) face challenges in ensuring high-speed rewriting of internal nonvolatile memory and simultaneous backup to external nonvolatile memory, especially when transitioning from wired to over-the-air (OTA) updates.
Innovation Solution
An electronic control device is designed with a microcomputer that includes internal and external nonvolatile memories, as well as communication units for both internal and external devices. This configuration allows the microcomputer to write received data from an external device to both internal and external nonvolatile memories, enabling high-speed rewriting and backup processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the control software is rewritten using the double bank method by dividing the internal nonvolatile memory into two areas, then the control software can be updated via OTA during normal vehicle use, but the internal nonvolatile memory capacity requirement doubles, increasing hardware cost and complexity
Solution Approach 1:
The patent segments the nonvolatile memory into a first nonvolatile memory for storing the control program and a second nonvolatile memory for storing backup data. This segmentation allows the control program to be rewritten in the first memory while maintaining backup capability in the second memory, enabling OTA updates without requiring the entire internal memory to be doubled in capacity.
Solution Approach 2:
The patent implements a copying mechanism where the control program stored in the first nonvolatile memory is copied to the second nonvolatile memory as backup data before rewriting. This copying approach enables the system to maintain a backup version of the control program without requiring the first nonvolatile memory to have doubled capacity, thus reducing hardware cost while supporting OTA update functionality.
2Productivity
If the control software is rewritten using the wired method in a repair shop, then high-speed rewriting can be achieved, but the control software cannot be updated during normal vehicle use and requires user storage time and effort
Solution Approach 1:
The patent creates a dynamic update system where the control program can be rewritten in the first nonvolatile memory while the backup remains in the second nonvolatile memory. This dynamic structure allows the system to support both high-speed wired rewriting (when needed in repair shops) and convenient OTA updates (during normal use), as the backup mechanism enables safe in-place rewriting without requiring user intervention or storage time.
3Reliability
If backup data is stored in the external nonvolatile memory before rewriting, then the control software can be rolled back if update fails, but the processing time increases due to additional write operations
Solution Approach 1:
The patent implements preliminary action by copying the control program from the first nonvolatile memory to the second nonvolatile memory before performing the rewrite operation. This preliminary backup action ensures that if the rewrite fails, the system can roll back to the previous version stored in the second memory. The patent optimizes this process by performing the copy operation efficiently and only when necessary, minimizing the time added to the overall processing while maintaining reliable rollback capability.
Data Source
AI summary
An electronic control device includes: a microcomputer including a processor that executes a predetermined program; and an external nonvolatile memory connected to the microcomputer, in which the microcomputer includes an internal nonvolatile memory, a first communication unit that communicates with the external nonvolatile memory, and a second communication unit that communicates with an external device, and the microcomputer writes data, which is received from the external device and rewrites the internal nonvolatile memory, in the internal nonvolatile memory and the external nonvolatile memory.