Semiconductor memory
AssigneeRohm Co., Ltd.
InventorsHiromi Uenoyama, Hiroki Takagi
Life of this patent
Estimating the term…
Abstract
A semiconductor memory has a main memory and an ID memory, of which both store data in a nonvolatile memory. The data stored in the ID memory is compared with data entered from outside by a verifying circuit. Whether access to the main memory is permitted or not depends on the result of the verification by the verifying circuit. The operation code for accessing the ID memory is different from the operation code for accessing the main memory. The operation code for the ID memory is changed in accordance with the data stored in the ID memory.
Claims22
A semiconductor memory comprising:
- first memory means for storing data;
- second memory means for storing ID data;
- verifying means for checking whether data for comparison is identical with the ID data stored in the second memory means;
- means for permitting access to the first memory means when a first operation code is entered only if the verifying means judges that the data for comparison is identical with the ID data stored in the second memory means;
- verification control means for making the verifying means check, when a second operation code that is different from the first operation code is entered, whether data entered from exterior circuits combined with the second operation code is identical with the ID data;
- and
- operation code changing means for changing the second operation code, which is used to activate the verifying means, in accordance with the data stored in the second memory means.
A semiconductor memory comprising:
- first memory means for storing data;
- second memory means for storing ID data;
- verifying means for checking whether data entered as ID data is identical with the ID data stored in the second memory means;
- read/write control means for controlling reading and writing operations performed on the first memory means;
- and
- a command decoder for producing a driving signal for driving the read/write control means,
- wherein the command decoder out puts the driving signal when a first operation code is entered only if the verifying means outputs a permission signal, and the command decoder outputs a signal for activating the verifying means when a second operation code is entered.
A game cassette having a program memory for storing a program and a backup memory for storing data in accordance with progress of the program being executed, wherein said backup memory comprises:
- first memory means for storing data;
- second memory means for storing ID data;
- verifying means for checking whether data entered for comparison is identical with the ID data stored in the second memory means;
- means for permitting access to the first memory means when a first operation code is entered only if the verifying means judges that the data for comparison is identical with the ID data stored in the second memory means;
- verification control means for making the verifying means check, when a second operation code that is different from the first operation code is entered, whether data entered for comparison together with the second operation code is identical with the ID data;
- and
- operation code changing means for changing the second operation code, which is used to activate the verifying means, in accordance with the data stored in the second memory means.
A game cassette having a program memory for storing a program and a backup memory for storing data in accordance with progress of the program being executed, wherein said backup memory comprises:
- first memory means for storing data;
- second memory means for storing ID data;
- verifying means for checking whether data entered as ID data is identical with the ID data stored in the second memory means;
- read/write control means for controlling reading and writing operations performed on the first memory means;
- and
- a command decoder for producing a driving signal for driving the read/write control means,
- wherein the command decoder outputs the driving signal when a first operation code is entered only if the verifying means outputs a permission signal, and the command decoder outputs a signal for activating the verifying means when a second operation code is entered.
Dependencies are inferred from the claim text.