| 摘要 |
<p>PROBLEM TO BE SOLVED: To reset only a specific internal circuit to an initial state in the case of restoring operation after the drop of power supply voltage by selectively initializing at least one of plural internal circuits when a detection signal is inputted and then setting up the selected internal circuit to an initial state. SOLUTION: When power supply voltage VDD is dropped, a low voltage detection circuit 2 outputs a low voltage detection signal (a) of a high level. The signal (a) is inputted to a 2nd OR circuit 14, and at the time of inputting a high level signal, a 2nd initialization signal (g) of a high level is inputted to the reset terminal of an I/O circuit 10. Thereby only the I/O circuit 10 is initialized. On the other hand, the signal (a) is inputted also to a PC setting circuit 5. At the time of inputting the signal (a) of the high level, the circuit 5 outputs a PC specification value setting signal (h) for changing an address indicated by a PC 8 to the leading address of an area storing an instruction program for setting up the initial state of the circuit 10 to the PC 8.</p> |
