| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor storage device where a password protection function of a high degree of freedom is realized by having the password protection function which prohibits reading of a part of or the whole blocks of memory blocks without releasing operation using the password so as to ensure the password protection function after prescribed operation such as reset operation. <P>SOLUTION: In state control of effectiveness/ineffectiveness of the password protection function based on a first state regulation value M and a second state regulation value P, the password protection function becomes effective when the first state regulation value M and the second state regulation value P are in a set state, and the password protection function becomes ineffective when at least the second state regulation value P is in a reset state. With respect to reset operation, the first state regulation value M has a property of keeping a former state, and the second state regulation value P has a property of following the state of the first state regulation value M. Thus, only when input of the password is proper, the releasing operation of making the second state regulation value P into the reset state is possible. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
