| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a semiconductor memory device for quickly changing the data protection state of a nonvolatile memory, and also having a sufficient security strength. <P>SOLUTION: The data protection/deprotection state of the nonvolatile memory is specified by volatile protection state specifying sections, and the state of the protection states specifying sections is stored by nonvolatile initial state storage sections. Further, the fixed/unfixed state of the protection state specifying sections are set by a volatile protection state fixing sections, and the initial state of the protection states fixing section is decided by a nonvolatile storage section for password mode and nonvolatile storage section for non-password mode. In the case of password mode decided by the storage section for password mode, authentication by the password is required to change the setting of protection state fixing section. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
