Abstract: A system for detecting inductive objects includes an inductive sensor circuit for detecting changes in an electromagnetic field (“EMF”) environment and an integrated circuit (“IC”) device. The inductive sensor circuit generates an oscillating analog waveform with an envelope that indicates changes in the EMF environment. The oscillating waveform is coupled to the digital input pin of the IC. A digital interface circuit in the IC is coupled to the digital input pin and is configured for detecting if the oscillating waveform exceeds high and low threshold voltage levels. The detecting results in a digital pulse which represents changes in the EMF environment. In another implementation, a timer input capture pin can be used to detect the waveform envelope decay by storing the time when the waveform crosses a threshold value during a time period. A reduced capture time after the time period expires indicates a change in the EMF environment.

Abstract: An system for detecting inductive objects includes an inductive sensor circuit for detecting changes in an electromagnetic field (“EMF”) environment and an integrated circuit (“IC”) device. The inductive sensor circuit generates an oscillating analog waveform with an envelope that indicates changes in the EMF environment. The oscillating waveform is coupled to the digital input pin of the IC. A digital interface circuit in the IC is coupled to the digital input pin and is configured for detecting if the oscillating waveform exceeds high and low threshold voltage levels. The detecting results in a digital pulse which represents changes in the EMF environment. In another implementation, a timer input capture pin can be used to detect the waveform envelope decay by storing the time when the waveform crosses a threshold value during a time period. A reduced capture time after the time period expires indicates a change in the EMF environment.