Memory Device Register Protection Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Nonvolatile memory devices, such as BIOS memory, face challenges in protecting stored data from improper alteration or deletion, which can lead to system malfunction if the information is not securely retained.
Innovation Solution
A memory device is designed with a register-protection bit that locks a protection area until a reset event, utilizing a status register with write-protect bits and a security register with register-protection bits to prevent unintended state changes, ensuring data integrity by controlling access and modifications within the memory array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nonvolatile memory device stores critical information such as boot codes and serial numbers, then the data retention capability is improved, but the vulnerability to improper alteration or deletion increases
Solution Approach 1:
The memory device is segmented into multiple functional components: a memory array for data storage, a status register for protection status, and a security register for write-protection control. This segmentation allows critical data to be stored while implementing layered protection mechanisms that prevent improper alteration.
Solution Approach 2:
The write-protection mechanism is activated in advance through the security register before any potential improper alteration can occur. The status register is configured with protection bits that are set beforehand to prevent unauthorized writes to critical memory regions, ensuring data integrity from the outset.
2Reliability
If write-protection mechanisms are implemented to prevent data alteration, then data security is improved, but the device complexity increases
Solution Approach 1:
The security register and status register serve multiple functions: they not only provide write-protection but also track protection status and enable conditional access control. This multi-functionality reduces the need for separate dedicated protection circuits, thereby limiting the increase in device complexity.
Solution Approach 2:
The protection mechanism is nested within the existing memory device architecture. The security register contains write-protection bits that control the status register, which in turn controls access to the memory array. This nested structure integrates protection functionality without requiring a completely separate protection system.
3Reliability
If the protection status is maintained across power cycles, then data integrity is improved, but the loss of time for resetting protection increases
Solution Approach 1:
The write-protection mechanism maintains protection status across power cycles through the nonvolatile security register, but allows selective resetting. Instead of requiring complete system reset, only the security register needs to be cleared to restore write access, reducing the time loss compared to full system initialization.
Data Source
AI summary
A memory device comprises a memory array, a status register, a status-register write-protect bit and a security register. The memory array contains a number of memory blocks. The status register includes at least one protection bit indicative of a protection status of at least one corresponding block of the memory blocks. The status-register write-protect bit is coupled with the status register for preventing a state change of the at least one protection bit. The security register includes at least one register-protection bit for preventing the state change in one of the at least one protection bit of the status register and the status-register write-protect bit.