Storage device
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorMasanori Matsuura
Life of this patent
Estimating the term…
Abstract
A data mask section outputs memory data read from a memory array unit for a predetermined time period that is shifted from an edge timing of a clock signal, while a microcomputer takes in the data output from the data mask section at the edge timing of the clock signal. Thus, the microcomputer is capable of appropriately taking in the memory data only when the frequency of the clock signal is within a predetermined range, and accordingly, it is difficult to fraudulently obtain the memory data. Furthermore, the data mask section may output random data, or the like, during a time period other than the predetermined time period. In such a case, it is difficult to analyze the memory data, and the confidentiality of the memory data is improved.
Claims12
A storage device, comprising:
- a memory;
- a microcomputer for taking in data read from the memory according to a externally-supplied clock signal or a clock signal generated based on the externally-supplied clock signal;
- a timing signal output circuit for outputting a timing signal indicative of a timing that is shifted by a predetermined time period from a predetermined edge in a read control signal which is used for controlling reading of data from the memory;
- and
- a read data control circuit for performing control such that the microcomputer takes in the data read from the memory based on the timing signal only when the clock signal has a predetermined frequency.
A storage device, comprising:
- a memory;
- a microcomputer for taking in data read from the memory according to a externally-supplied clock signal or a clock signal generated based on the externally-supplied clock signal;
- a mask circuit for outputting the data read from the memory to the microcomputer for a predetermined time period;
- and
- a timing control circuit for performing control such that the predetermined time period during which the mask circuit outputs the data read from the memory and the timing for taking the data output from the mask circuit into the microcomputer are variable.
Dependencies are inferred from the claim text.