Memory Card Controller Updating Capacity for Bad Blocks
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Solution Overview
Problem
Conventional memory card apparatuses do not provide accurate available memory capacity information to host devices, as they only transmit total memory capacity without reflecting the occurrence of bad memory blocks, leading to unrecognized actual available memory capacity.
Innovation Solution
A memory card apparatus with a controller that updates and transmits available memory capacity information by calculating and reflecting bad memory capacity, which is stored in a CSD register, ensuring the host device receives accurate memory capacity information by subtracting unavailable memory capacity from the total capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the memory card apparatus transmits total memory capacity information without updating for bad memory blocks, then the host device can recognize the total capacity, but the host device cannot recognize the actual available memory capacity excluding bad memory blocks
Solution Approach 1:
The controller proactively updates the memory capacity information in the CSD register to reflect bad memory blocks before the host device requests capacity information. This preliminary update ensures that when the host device queries the memory capacity, it receives accurate available capacity information that already accounts for bad blocks, eliminating the need for the host to detect or calculate unavailable capacity.
Solution Approach 2:
The controller continuously monitors the status of memory blocks and dynamically updates the capacity information in the CSD register based on detected bad blocks. This feedback mechanism ensures that the memory capacity information transmitted to the host device always reflects the current actual available capacity, maintaining measurement precision while preventing information loss about unavailable capacity.
2Measurement precision
If the memory card apparatus stores and transmits updated available memory capacity information reflecting bad memory blocks, then the host device can recognize actual available memory capacity, but the device complexity increases due to continuous monitoring and updating
Solution Approach 1:
The controller merges the function of monitoring bad memory blocks with the existing capacity information management in the CSD register. By combining these functions, the controller updates the same register structure that already stores capacity information, avoiding the need for separate complex tracking systems and reducing overall device complexity while maintaining measurement precision.
Solution Approach 2:
The controller automatically monitors memory block status and self-updates the capacity information in the CSD register without requiring external intervention or complex host-device coordination. This self-service approach simplifies the system by making the controller independently manage its own capacity information accuracy, reducing the burden on both the controller and host device.
Data Source
AI summary
A memory card apparatus includes a non-volatile memory and a controller configured to control the non-volatile memory and communicating with the host device, wherein the controller updates available memory capacity information according to occurrence of bad memory in the non-volatile memory and transmits the updated memory capacity information to a host device.