ECU Program Update Decompression for Limited Volatile Memory
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Solution Overview
Problem
Existing methods for updating electronic control units (ECUs) in vehicles face challenges in reducing reprogramming time due to limited volatile memory capacity, which restricts the size of the reference dictionary and compression rate, leading to insufficient speed-up in program updates when switching between different update systems.
Innovation Solution
A control apparatus and program update system that includes a reception unit for receiving compressed data, a decompression unit that switches decompression methods based on an update system designated in a header, and a restoration unit for updating the program, allowing for efficient decompression and restoration of new program data even with limited volatile memory capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of the reference dictionary is increased to improve compression rate, then the compression rate increases, but the volatile memory capacity requirement increases
Solution Approach 1:
The patent divides the reference dictionary into two separate storage areas: a first storage area in volatile memory for frequently accessed dictionary data, and a second storage area in non-volatile memory for additional dictionary data. This segmentation allows the system to achieve a larger effective dictionary size for compression while keeping the volatile memory footprint small, thus resolving the contradiction between compression rate and memory capacity requirements.
2Productivity
If the decompression buffer capacity is increased to support larger reference dictionary, then the compression rate can be increased, but the hardware resource margin decreases
Solution Approach 1:
The patent segments the buffer into a first buffer in volatile memory and a second buffer in non-volatile memory. The first buffer holds actively used dictionary data during decompression operations, while the second buffer provides additional storage capacity without consuming valuable volatile memory resources. This allows the system to maintain high compression rates while preserving hardware resource margins.
3Device complexity
If a single update system is used for all ECUs, then the system is simpler to manage, but the reprogramming time increases for ECUs with many programs
Solution Approach 1:
The patent implements a dynamic update system selection mechanism where the control apparatus can switch between a first update system (using volatile memory-based dictionary) and a second update system (using non-volatile memory-based dictionary) based on the specific ECU's characteristics and update requirements. This dynamic approach allows optimization of reprogramming time for different ECUs without significantly complicating the overall system management.
Data Source
AI summary
A control apparatus includes a reception unit which receives distribution data which contains compressed update data and a header which includes information to designate any one of a plurality of update systems, a decompression unit which decompresses the update data from the distribution data received by the reception unit, and a restoration unit which restores a new program after updating according to an update system designated in the header using the update data decompressed by the decompression unit. The decompression unit switches a decompression method when the update data is decompressed on the basis of the update system designated in the header.