Button-press detection and filtering

摘要

The disclosure provides a button-press detection and filtering method, related circuit, and button-press detection chip for a external device. A button-press signal from a wire control apparatus is coupled to the button-press detection chip for the external device. The button-press detection chip for the external device can digitally sample the button-press signal through the filter circuit and outputs a digital logic signal corresponding to a button to an audio codec according to the sampling result. The audio codec can determine a pressed button according to the digital logic signal and performs a corresponding function. With the solutions of the disclosure, a noise interference signal in a button-press signal may be avoided and a pressed button may be accurately detected, without using a dedicated chip or complex software codes in a wire control apparatus and an electronic device.

主权项

1. A button-press detection circuit, comprising:
a filter circuit configured to digitally sample a button-press signal from a button on a wire-control apparatus of an external device, to determine a pressed button on the wire-control apparatus using the digital sample, and to provide a digital logic signal to cause an audio codec to perform a function corresponding to the pressed button, wherein the filter circuit includes: a comparator sampling circuit configured to compare a reference voltage to a voltage of the button-press signal; a sampling result register having a sampling rate, the sampling result register configured to receive an output of the comparator sampling circuit and to provide a count result using the output of the comparator sampling circuit and the sampling rate; and a logic processing circuit configured to determine the pressed button according to the count result and to output the digital logic signal corresponding to the pressed button.