| 摘要 |
An input device having reduced GPIO(General Purpose Input Output) ports is provided to optimize the structure of key buttons, and to decrease the number of sensing lines, thereby minimizing the number of the GPIO ports of a processor required for key sensing. n sensing lines(SL1-SL3) sequentially correspond with digits of n-digit binary numbers. At least more than one of key buttons(20) consists of reference voltage terminals(21) to which reference voltages are applied and n signal terminals(23) sequentially corresponding with the digits of the n-digit binary numbers by being formed on the outer circumference of the reference voltage terminals(21), and wherein a certain one of the n-digit binary numbers is assigned. |
