| 摘要 |
A key input includes a keypad device and a micro controller unit. The keypad device has a matrix consisted of first signals lines, second signal lines, and switches located in corners which are formed by the first and the second signal lines, and a plurality of keys corresponding to the switches. The micro controller unit connects the first signal lines and the second lines and provides a pulse to the first signal line. When the switch is turned on by the key, the pulse is translated from the first signal line to the second signal line. Thus, the pulse is directly detected, so as to achieve the fast scanning and low sensitive impedance of carbon membrane efficient. |
