Data protection method for a semiconductor memory and corresponding protected memory device

A semiconductor electronic memory device having a protection function for data stored therein, the memory device comprising:

• a memory matrix;
• a pre-decoding block having a memory address to be decoded;
• a decoding block having an input connected to the pre-decoding block and an output coupled to the memory matrix;
• a protected memory portion incorporated with said matrix;
• a command interpreter receiving control signals and having an output coupled to said protected memory portion;
• a programmable code filter having a data input and an output connected to an input of the command interpreter;
• and
• a plurality of dedicated decoding portions having an input coupled to the output of the command interpreter and an output coupled to the protected memory portion, the dedicated decoding portions being structured to decode a selection signal from the command interpreter and, in response to the selection signal, access the protected memory portion.

A memory system, comprising:

• a memory matrix for storing information, the memory matrix including an unprotected portion from which data can be erased and a protected portion from which data cannot be erased;
• a command interpreter coupled to the memory matrix, the command interpreter being programmed with a special instruction that reads the protected portion without reading the unprotected portion;
• and
• a decoder coupled between the command interpreter and the memory matrix, the decoder having a decoding portion dedicated to the protected portion of the memory matrix and accessible by the special instruction of the command interpreter.