Flash Memory Controller RAM Multiplexing for Copy Operations
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Solution Overview
Problem
Existing flash memory systems face inefficiencies in copy operations due to reliance on external RAM, long processing times, and failure to utilize look-up RAM effectively, especially in systems lacking internal copy-back commands.
Innovation Solution
A method employing multiplexing techniques to efficiently copy data by searching for free sectors in flash memory using a look-up table, writing data to these sectors, and managing RAM space to maximize throughput without requiring large additional RAM, involving a system with a register module, comparator, and processor for executing read-write operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external RAM is used for copy operations in flash memory systems without internal copy-back commands, then the copy operation can be performed, but a large amount of RAM is required for temporarily storing data
Solution Approach 1:
The patent merges the LUT storage function with the copy buffer function by using the same RAM memory for both purposes. During copy operations, the RAM temporarily serves as both the LUT storage and the data buffer, eliminating the need for separate dedicated memory spaces and reducing total RAM requirements.
Solution Approach 2:
The RAM memory is designed to perform multiple functions: storing the LUT (logical-to-physical address mapping) and simultaneously serving as the buffer for copy operations. This multi-functional approach allows the system to perform copy operations without requiring additional dedicated RAM space.
2Quantity of substance
If a small part of RAM (512 Bytes) is used for multiple read-write operations, then RAM usage is minimized, but the processing time for copy operations increases significantly
Solution Approach 1:
The patent dynamically allocates and manages the RAM space for LUT and copy buffer based on the current operation state. The system can switch between different usage modes (LUT storage mode, copy buffer mode, or combined mode) to optimize performance while maintaining acceptable RAM usage levels.
3Quantity of substance
If the LUT is invalidated and rebuilt after copy operations, then the LUT RAM area can be reused, but the process becomes time consuming as all blocks need to be read again
Solution Approach 1:
The patent performs preliminary actions by maintaining the LUT in the RAM continuously and updating it incrementally during copy operations rather than invalidating and rebuilding it completely afterward. This approach prepares the LUT data in advance and updates it progressively, avoiding the time-consuming full rebuild process.
4Device complexity
If the LUT RAM area is not utilized during copy operations, then the RAM structure remains simple, but the available RAM capacity is wasted
Solution Approach 1:
The patent combines the LUT storage function with the copy buffer function in the same RAM memory, allowing the LUT RAM area to be utilized during copy operations without increasing the overall RAM structure complexity. The same memory space serves dual purposes.
Data Source
AI summary
A methodology for efficiently copying data is presented. An internal controller RAM is multiplexed between storing existing RAM data such as look up table data) and storing copy back data with respect to a flash memory. The data in the controller RAM is temporarily stored in a free space of the flash memory. The data of the flash memory, which is to be copied, is read from a source page and is stored in the free space of the controller RAM, and from there, the data is written to a destination block of the flash memory. After completion of the copy back operation, the data of the controller RAM that was moved to the free space is retrieved for storage back in the controller RAM.