| 摘要 |
PURPOSE:To prevent changes in the content of a storage circuit of a microcomputer at changeover from a compensating power supply to a normal use power supply by providing a reset circuit outputting a reset signal preventing the operation of a storage circuit. CONSTITUTION:A storage circuit 43 uses a battery 47 to hold the content of a RAM until a power supply is given to a system and selecting terminals are brought into non-selecting state. When a power is applied, the power is changed over into a stabilized power supply by a switching circuit 48, a reset circuit 63 outputs a reset signal L, and the output of a decoder circuit 64 brings the circuit 43 into the non-selecting state because a transistor (TR)67 is in off-state. When the reset circuit 63 outputs an H signal after the reset time is elapsed, a current flows to a base of the TR67 via a diode 66 and a resistor 70. When a computer 40 starts its operation and selects the circuit 43 and allows the circuit 64 to output an L signal, the TR67 is turned on, the L signal is outputted to the circuit 43, causing it to be activated. |
