Vehicle Keyless Ring Buffer for Complete Signal Acquisition
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Solution Overview
Problem
The control unit in vehicle keyless systems transitions from a sleep state to an operational state after receiving an interrupt signal, but during this transition, it may not acquire complete unit command signals due to the timing delay, leading to incomplete data acquisition and reduced communication accuracy.
Innovation Solution
The on-vehicle device employs a ring buffer to store received unit command signals and outputs an interrupt signal only when storage is complete, allowing the control unit to acquire data in a state where all signals are fully received, enabling accurate code analysis and command execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the control unit transitions from sleep state to operational state after receiving interrupt signal, then power consumption is reduced during idle periods, but data acquisition completeness deteriorates due to transition delay
Solution Approach 1:
The reception unit performs preliminary action by continuously receiving and storing unit command signals in the ring buffer even before the control unit is fully operational. This allows the control unit to acquire complete data sets without waiting for signal reception to finish, resolving the contradiction between power saving (sleep mode) and data completeness.
2Speed
If the control unit acquires data immediately after transitioning to operational state, then response performance is improved, but data completeness deteriorates due to ongoing signal reception
Solution Approach 1:
The ring buffer acts as an intermediary between the reception unit and the control unit. It temporarily stores incoming unit command signals, allowing the control unit to acquire complete data sets at its convenience without interfering with the continuous reception process, thus resolving the conflict between response speed and data completeness.
3Productivity
If multiple unit command signals are transmitted with short time intervals to improve communication efficiency, then productivity is improved, but data acquisition reliability deteriorates due to control unit transition timing
Solution Approach 1:
The reception unit continuously performs preliminary reception and storage of multiple unit command signals in the ring buffer before the control unit needs them. This allows high-speed transmission with short time intervals while ensuring the control unit always acquires complete data sets, resolving the contradiction between communication efficiency and data reliability.
Data Source
AI summary
At acquisition of a first unit command signal RC(1) of which storage is completed and in a case that the ring buffer stores a part of a second unit command signal RC(2), the CPU acquires the first unit command signal and the part of the second unit command signal upon receiving a first interrupt signal BQ(1), and then separates the first unit command signal and the part of the second unit command signal from each other. When having received a second interrupt signal BQ(2), the CPU acquires the remaining of the second unit command signal, and combines the remaining of the second unit command signal and the part of the second unit command signal. Accordingly, the second unit command signal once separated is acquired as a signal having all data completed.