INPUT CIRCUIT FOR SETTING OPERATION MODE OF MICROCOMPUTER

摘要

PROBLEM TO BE SOLVED: To provide the input circuit equipped with a means which cuts off the current path from the pull-up element of an input terminal. SOLUTION: The potential of an input terminal I1 is pulled up to a power source potential VDD by a P channel MOS transistor(TR) P1 and connected to one input terminal of a NOR circuit 101 through an N channel MOS TR N1. The other input terminal of the NOR 101 is connected to an input terminal I2 and the output terminal of the NOR 101 is connected to the gate electrode of the P channel MOS TR P1 and the input terminal of an inverter 102 respectively. The output terminal of the inverter 102 is connected to one input terminal of the NOR 101 through a TR N2. The input terminal I2 is further connected to the gate electrode of the TR N1 and the input terminal of the inverter 104 through a delay circuit 103, and the output terminal of the inverter 104 is connected to the gate electrode of the TR N2.