Nonvolatile semiconductor memory device with security function and protect function

摘要

The invention provides a flash memory having a security function and a protect function. When the release of the security function has been instructed, all data stored in each block of a flash memory main body is forcibly erased, ignoring the setting of the protect function. After that, the security function is released, thereby enabling readout of data. This being so, even if a third person releases the security function, leakage of data to the outside can be prevented.