Mask ROM and Programmable ROM Mapping for Cost-Effective Reprogramming

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Solution Overview

Problem

Existing ROM technologies face challenges in balancing cost-effectiveness and re-programmability, as mask ROMs are inexpensive but non-reprogrammable, while reprogrammable options like EEPROMs and Flash ROMs are costly and inconvenient for mass production.

Innovation Solution

A memory storage device combining a mask ROM with a smaller programmable ROM, where the programmable ROM stores mapping information and replacement data, allowing selective reprogramming of sections without altering the entire device, and utilizing error correction codes to verify data integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If mask ROM is used, then manufacturing cost is reduced, but re-programmability is lost

Engineering Contradiction:

Improvemanufacturing costVSAvoidre-programmability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The memory device is divided into two distinct segments: a mask ROM portion for storing immutable data and a programmable ROM portion for storing reprogrammable data. This segmentation allows each portion to be optimized for its specific function, maintaining low manufacturing costs while enabling re-programmability where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent combines mask ROM and programmable ROM into a single integrated memory device. The controller manages both portions, allowing the system to benefit from both the cost-effectiveness of mask ROM and the re-programmability of programmable ROM within one unified structure.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If programmable ROM is used, then re-programmability is improved, but manufacturing cost increases

Engineering Contradiction:

Improvere-programmabilityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Instead of making the entire memory device programmable, only a specific portion (the programmable ROM portion) is made reprogrammable. This local application of programmability reduces manufacturing costs compared to fully programmable ROM while still providing re-programmability for specific data needs.

Inventive Principle:

Principle #3Local quality

3Loss of information

If entire mask ROM is reprogrammed, then data updates are achieved, but manufacturing waste increases

Engineering Contradiction:

Improvedata update capabilityVSAvoidmanufacturing waste

Core Design Contradiction:

Loss of informationVSLoss of substance

Solution Approach 1:

The patent extracts the reprogrammable data portion from the larger mask ROM structure and places it in a separate programmable ROM portion. This allows updates to be made only to the necessary data segments without requiring reprogramming or discarding of the entire memory device, thereby reducing manufacturing waste.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS7533240B1Device with mapping between non-programmable and programmable memory

Publication Date: 2009.05.12 MARVELL ASIA PTE LTD

AI summary

A memory storage device connectable to a bus comprises a first memory module that stores data, a second memory module that is capable of being programmed, and a memory controller that communicates with the first memory module, the second memory module, and the bus, and that determines an address mapping of selected areas of the first memory module onto the second memory module. When the memory controller receives an access request from the bus, the memory controller accesses data from the first memory module unless the address mapping specifies that the access request maps to the second memory module, whereupon the memory controller accesses replacement data from the second memory module.