Detecting accessories on an audio or video jack

Abstract

A detection circuit can be configured to receive a digital value from an identification register and to determine a resistance at a conducting terminal of an audio or video jack plug using the digital value. The detection circuit can include a current source that outputs a current according to the digital value from the identification register and a comparator that compares a reference voltage to a voltage created by the current source across the resistance at the conducting terminal of the audio or video jack plug. A control logic circuit can be configured to store the digital value in the identification register, generate an interrupt signal to cause a processor to read the digital value, and identify a function of an accessory device including the audio or video jack plug, when the detection circuit determines the resistance at the conducting terminal of the audio or video jack plug.

Dependencies are inferred from the claim text.