| 摘要 |
An improved memory device and architecture has been detailed that enhances a Flash memory device that has an SDRAM compatible READ interface. The memory device employs a virtual paging scheme that allows for the architecture of the memory to implement an efficient Flash memory structure internally. Externally, the memory logically maps the internal Flash architecture to an SDRAM compatible interface and virtual architecture, allowing for memory access and operation with a compatible SDRAM controller device. Programming, erasing, block protection, and other Flash specific functions differ from SDRAM and are performed with an SDRAM command sequence. A memory device may have four times as many rows in a memory array bank as a comparable SDRAM device, but only one fourth as many columns. This reduces the number of sense amplifiers activating, therefore saving power and complexity in the memory device. Internal to the memory, memory array banks are divided into four equal segments by row range and logically re-mapped by placing the segments virtually beside each other. This logically re-mapped memory bank forming a virtual memory bank structure of equivalent rows and columns as the comparable SDRAM device. A memory device may have an extended memory interface with additional address lines, allowing for direct access to the internal Flash memory architecture without the abstraction of logical re-mapping the internal memory array. Additionally, the extended interface allows for full bank association and mapping of a segment row of an activated virtual row page to any segment of the bank for a subsequent memory access. More segments are available for the memory device versus a comparable SDRAM. Therefore, a memory has a higher hit rate for READs without necessitating activation of further new rows. This increases the memory array granularity and has the effect of decreasing power and latency. The improved latency effectively increases the available bandwidth of the memory device.
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