Patent ID: 7800025

Claim:
A method for detecting states of a plurality of touch switches, comprising: (a) determining one of the touch switches for detection; (b) setting source of a first counter; (c) configuring the first counter and a second counter to stop counting when the first counter overflows; (d) initializing the first counter and the second counter; (e) starting a RC oscillator, the first counter and the second counter; (f) determining whether the first counter and the second counter stop or not; (g) storing content of the first counter in a first memory(X 0 ) of a micro-controller; (h) initializing the first counter; (i) setting content of the second counter to 0; (j) starting the RC oscillator, the first counter and the second counter; (k) determining whether the first counter and the second counter stop or not; (l) storing content of the first counter in a second memory(X 1 ) of the micro-controller; (m) determining whether (X 0 -X 1 ) is larger than a sensitivity value or not; and (n) repeating the steps (i) to (m).