Embedded Controller Data Recovery via BIOS and NVRAM Backup
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Solution Overview
Problem
Embedded controllers with only volatile memory lose data when entering a power-off mode, leading to functional failures upon recovery, especially when they lack non-volatile memory or a real-time clock function.
Innovation Solution
A data recovery method that backups data from an embedded controller to non-volatile random access memory (NVRAM) during power-off and restores it upon power restoration, using the BIOS to manage data consistency and real-time clock information for correct time calculation and scheduled activations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the embedded controller uses only volatile memory to store data, then the device complexity is reduced and cost is lowered, but data is lost when the controller enters power-off mode
Solution Approach 1:
The BIOS performs preliminary action by backing up data from the embedded controller's volatile memory to the NVRAM before the controller enters power-off mode. This proactive data preservation ensures that when power is restored, the original data can be recovered, thus resolving the contradiction between using simple volatile memory and preventing data loss.
Solution Approach 2:
The NVRAM serves as an intermediary storage medium between the embedded controller and the BIOS. It temporarily holds backup data during power-off periods, enabling data recovery without requiring the embedded controller to have its own non-volatile memory, thus maintaining device simplicity while preventing information loss.
2Device complexity
If the embedded controller lacks a built-in real-time clock function, then the device complexity and cost are reduced, but the controller cannot correctly calculate or determine current time after recovery
Solution Approach 1:
The BIOS acts as an intermediary that provides real-time clock information to the embedded controller after recovery. Instead of requiring the controller to have its own clock hardware, the BIOS supplies the necessary time data, enabling the controller to correctly calculate current time while maintaining a simple device structure.
Solution Approach 2:
The BIOS performs multiple functions including data backup, time information provision, and system initialization. By making the BIOS multi-functional, the system eliminates the need for dedicated real-time clock hardware in the embedded controller, thus reducing device complexity while maintaining time measurement capability.
3Use of energy by moving object
If the embedded controller enters power-off mode to save energy, then energy consumption is reduced, but the controller cannot provide related functions after recovery due to data loss
Solution Approach 1:
The system performs preliminary data backup to NVRAM before the embedded controller enters power-off mode. This ensures that when the controller wakes up, the data is already preserved and can be quickly restored, allowing the controller to regain full functionality without prolonged disruption, thus maintaining reliability while enabling energy-saving mode.
Solution Approach 2:
The embedded controller discards data temporarily during power-off mode by relying on the backup in NVRAM, and then recovers the data after power restoration. This discard and recover mechanism enables the controller to save energy during idle periods while ensuring functional reliability is restored upon wake-up.
Data Source
AI summary
A computer system and a data recovery method are provided. The computer system includes an embedded controller (EC). The data recovery method includes following steps. When the computer system stores data into the EC through a basic input/output system (BIOS), the data is backed up into a non-volatile random access memory (NVRAM) by the BIOS. The EC enters a power-off mode. The data is obtained from the NVRAM and is stored back to the EC after the EC leaves the power-off mode. Accordingly, the EC recovers from the power-off mode.