| 摘要 |
PROBLEM TO BE SOLVED: To provide a key input device that can reliably identify either input key even if two input keys are pressed simultaneously and can implement the identification by means of a minimum number of resistors. SOLUTION: A key input circuit 10 has eight input keys and six resistors (two resistors having a resistance value of R0 and resistors having respective resistance values of R1 to R4) and sets R1 and R2 sufficiently lower than R3 and R4 to provide characteristics of two voltage values input into a first input port 161 and a second input port 162 when the eight input keys are pressed. By executing an input key identification program 142 using a conversion table 141, a CPU 120 can not only identify the type of an independently pressed input key but also identify that either input key has been pressed independently even if any two input keys are pressed simultaneously. COPYRIGHT: (C)2009,JPO&INPIT
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