| 摘要 |
<p>PROBLEM TO BE SOLVED: To cancel incomvenience to rewrite data already written in an address by inhibiting the data rewriting operation of a non-volatile memory unless the size of an address area in the non-volatile memory is established. SOLUTION: An external equipment is connected to a one-chip microcomputer. When address data of the address area A of EEPROM 1 is supplied from the external equipment to the one-chip microcomputer and latched by a latch circuit 4, fear that the program of the address area A is rewritten exists. Then, an address detecting circuit 18 detects that address data outputted from the latch circuit 4 belongs to the address area A of EEPROM 1, keeps a mode control signal MODE to be in a high level and inhibits that EEPROM 1 becomes the writing mode. Thus, incomvenience that data of the address area A of EEPROM 1 is rewritten is eliminated.</p> |
