| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a useless power consumption in a switch reader for reading the setting conditions of a switch. SOLUTION: First ends of switches S1-S8 are connected to a power source (+V) through pull-up resistors R1-R8, and second ends are connected to the output of an AND circuit 4. The output of the AND circuit 4 is at a low level only in the duration of outputting a reading signal (RD) from a CPU 2 and sending a chip select signal (CS) from an address decoder 3 and at a high level (+V) in other durations. When the AND circuit 4 is at the low level on the output, a current flows on the route from the power source to the output of the AND circuit 4 via the pull-up resistor group, and the switch set on, while the levels on the first ends of the switches S1-S8 are inputted to the CPU 2 via a gate circuit 8 and a data bus 7. COPYRIGHT: (C)2005,JPO&NCIPI
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