| 摘要 |
<p>PURPOSE: To improve the operability of a user by discriminating an undefined command, making it invalid, and preventing an operation mode signal from being generated in a nonvolatile semiconductor memory controlling an operation mode by a software command. CONSTITUTION: An input command is latched by a latch circuit 102, decoded to a mode signal by a command decoder circuit 103 of a mode setting circuit, made a 'H' level corresponding to the command in a NOR circuit 104, then lowered to a 'L' level to generate pulses by a pulse generation circuit 105. Then, when an undefined command is inputted, all output mode signals of the command circuit 103 are made a 'L' level, the NOR circuit 104 is kept in a 'H' level, and pulses are not generated. Therefore, a transfer gate 106 is kept in an OFF state, an output of the latch circuit 102 is not transmitted to a mode latch circuit 108, and a state before inputting a command is held.</p> |
