Electronic Device and Audio Accessory Having a Plurality of Passive Switches for Controlling the Audio Device

摘要

According to some aspects, a system for controlling an electronic device including an audio accessory coupled to the electronic device. The audio accessory has at least one speaker adapted to provide audio output and a plurality of resistive switches. The electronic device has a bias voltage source adapted to provide power to the resistive switches via a bias resistor and a ground connection, and a measurement module. The measurement module is adapted to monitor a bias point to determine which of the at least one switch has been engaged based on effect of the resistive switches on the ground offset voltage after compensating for a ground offset voltage caused by the audio output.