Apparatus and scanning method for key input apparatus

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.

主权项

1. A key input apparatus, comprising:
a keypad device having a matrix crisscross formed by a plurality of first signal lines and a plurality of second signal lines, each cross of said matrix having a switch coupled to adjacent said first signal line and said second signal line electrically, said keypad device further comprising a plurality of keys corresponded to said switch; and a micro controller unit coupling said plurality of first signal lines and said plurality of second signal lines, said micro controller unit configured to generate a pulse signal and configured to transfer said pulse signal to said plurality of first signal lines and configured to detect said plurality of second signal lines, wherein, when said plurality of keys turn on a corresponding switch, said micro controller unit detects said pulse signal on said second signal line which transferred from said first signal line, wherein said first signal line and said second signal line are electrically coupled to said corresponding switch.