Vehicle ECU Wake-Up Control for Multi-Signal Validation
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Solution Overview
Problem
Existing electronic control units for vehicles face limitations in handling multiple wake-up signals due to limited input trigger signals, high energy consumption, and a 'black hole' period where input trigger signals may be wrongly processed, leading to inefficiencies and increased costs.
Innovation Solution
The design incorporates two microcontrollers connected via a communication channel, where the first microcontroller wakes up the second and confirms whether input trigger signals are valid wake-up events or glitches, reducing energy consumption and allowing for flexible and scalable processing of multiple inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single microcontroller and SBC are used with limited input trigger signals, then device complexity is reduced, but the number of wake-up signals is limited resulting in high costs for designs with multiple wakeups
Solution Approach 1:
The system is segmented into two microcontrollers: a first microcontroller that remains active and monitors multiple input trigger signals, and a second microcontroller that sleeps and is awakened selectively. This segmentation allows the first MCU to handle multiple wake-up sources without requiring the second MCU to continuously monitor all inputs, thereby increasing adaptability while managing complexity.
Solution Approach 2:
The first microcontroller performs preliminary monitoring of all input trigger signals while the second microcontroller sleeps. When a trigger signal is detected, the first MCU preliminarily evaluates it and only awakens the second MCU if the signal is confirmed as valid. This preliminary action prevents unnecessary wake-ups and reduces the complexity burden on the sleeping MCU.
2Speed
If the second microcontroller wakes up immediately upon trigger signal, then response time is improved, but a 'black hole' period occurs where input trigger signals may change and be wrongly processed
Solution Approach 1:
The first microcontroller performs preliminary monitoring and validation of trigger signals before awakening the second microcontroller. It checks whether the trigger signal is stable and valid during a brief confirmation period, preventing the second MCU from waking up due to transient or invalid signals. This preliminary validation eliminates the 'black hole' problem while maintaining fast response to genuine triggers.
Solution Approach 2:
The system implements feedback through the first microcontroller continuously monitoring the trigger signals even after the second microcontroller has been awakened. If the trigger signal changes or proves invalid during the wake-up process, the first MCU can prevent or correct the wake-up action. This feedback mechanism ensures reliable signal processing while maintaining responsive operation.
3Use of energy by moving object
If the microcontroller stays asleep to reduce energy consumption below 100 uA, then energy efficiency is improved, but write-operations in non-volatile memory are limited to avoid memory problems
Solution Approach 1:
The system segments memory-related operations between two microcontrollers. The first MCU, which remains active, handles memory write operations and data buffering. The second MCU sleeps most of the time and only wakes up when necessary, minimizing its memory write operations. This segmentation allows the system to maintain low overall energy consumption while preserving memory lifetime by reducing total write operations.
Solution Approach 2:
The first microcontroller acts as a buffer or copy mechanism for data that needs to be stored. Instead of having the second MCU perform multiple small write operations while sleeping (which would consume energy and reduce memory lifetime), the first MCU collects and consolidates data, then performs fewer, more efficient write operations when the second MCU is active. This copying approach reduces memory stress while maintaining data integrity.
Data Source
Figure 1
AI summary
The invention relates to a method for waking up a second microcontroller (3) of an electronic control unit (1) for a vehicle, the electronic control unit (1) comprising a first microcontroller (2) connectable to a plurality of input trigger signals (4), whereby the second microcontroller (3) is communicatively connected with the first microcontroller (2) via a communication channel (5) and the second microcontroller (3) configured to fall asleep and to be woken up, the method comprising the steps of: waking up the second microcontroller (3) by the first microcontroller (2) in response to at least one of the input trigger signals (4); during the second microcontroller (3) wakes up, monitoring the at least one of the input trigger signals (4) by the first microcontroller (2); and asking the first microcontroller (2) by the second microcontroller (3) if the at least one of the input trigger signals (4) is confirmed as wakeup event.