Storage Device Data Output Circuit No-Write Region Handling
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Solution Overview
Problem
Conventional techniques for supplying ROMs with write-type nonvolatile memory are cumbersome, as they require lengthy manufacturing times and complex testing due to the need to write fixed values in no-write regions, which can contain unknown values, complicating the manufacturing and user testing processes.
Innovation Solution
A storage device with a memory core having distinct regions for program code, no-write region information, and fixed values, where a data selecting section outputs the fixed value when the physical address specifies the no-write region, simplifying the manufacturing process and satisfying user specifications by eliminating the need for active writing in the no-write region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed values are actively written to the no-write region in write-type nonvolatile memory, then user specifications are satisfied, but manufacturing time is lengthened
Solution Approach 1:
The patent extracts the fixed value output function from the physical writing process. Instead of actively writing fixed values to the no-write region, the system outputs predetermined fixed values directly from the memory circuit when read commands target the no-write region, eliminating the time-consuming writing step while satisfying user specifications
Solution Approach 2:
The patent creates a virtual copy of the fixed value data in the circuit logic rather than physically writing it to memory cells. The data output circuit generates fixed values (e.g., 00H, FFH) as copies of predetermined patterns, allowing the system to present correct data without the overhead of actual memory writing operations
2Manufacturing precision
If fixed values are actively written to the no-write region, then correct data is stored, but testing complexity increases
Solution Approach 1:
The patent removes the fixed value writing operation from the manufacturing process entirely. By using circuit logic to generate fixed values on-demand during read operations, the system eliminates the need for complex testing procedures that would verify whether fixed values were correctly written to the no-write region
3Ease of manufacture
If the no-write region stores unknown values, then manufacturing is simplified, but user testing becomes problematic
Solution Approach 1:
The patent introduces a data output circuit as an intermediary between the memory core and the external interface. This intermediary component intercepts read commands targeting the no-write region and substitutes unknown values with correct fixed values, allowing the memory core to remain simple while ensuring reliable data output
Solution Approach 2:
The system creates virtual copies of correct fixed value data through circuit logic rather than relying on physical storage. When the no-write region is accessed, the data output circuit generates accurate fixed values (00H, FFH, etc.) as logical copies, ensuring testing reliability without requiring actual data to be written in the memory cells
Data Source
AI summary
A memory is provided which simplifies the manufacturing process on the supplier side while satisfying specifications provided from the user side. An address space of a memory core includes an information storage region, a code region, and a no-write region. The information storage region includes a first region where no-write region information is written and a second region where a fixed value is written. Program code is written in the code region. The no-write region information indicates the position of the no-write region, and the fixed value indicates a fixed value that is intended to be written to the no-write region. The ROM selects between the fixed value and original read data that is obtained by a data selecting section directly from the memory core, and outputs the selected one as read data.