| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic circuit capable of recognizing multi-valued fixed information set on a substrate by using a delay circuit for delaying the rise time of a signal based on an inherent CR time constant and a pulse signal of a fixed period outputted from a counter with a single I/O signal. SOLUTION: A comparator compares a signal inputted from an I/O port with a pulse signal generated from the counter, detects which pulse turns the I/O port signal to H and outputs the hit pulse number to a register. Finally, values 1 to 4 stored in the register are returned as the read values. For instance, the resistance becomes 1 kΩby parallel connection of resistors R1, R5 when SW1=ON. In this case, a rise waveform becomes "1", "1" coincides with a pulse "1" and the value "1" is stored in the register. When any one of SWs 2 to 4 is ON, its corresponding value 2, 3 or 4 is similarly read. When all the SWs 1 to 4 are OFF, a resistor R5 is applied, and since the rise time of the resistor R5 is the slowest and cannot be detected even by "4", "0" is read. COPYRIGHT: (C)2004,JPO&NCIPI
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