Passive detection of device decoupling

Aspects of the present disclosure provide for a method. In at least some examples, the method includes controlling a switch to decouple a first node at which a pull-up signal is present from a second node. The method further includes measuring and storing a value of the pull-up signal as a reference value. The method further includes controlling the switch to couple the first node at which the pull-up signal is present to the second node. The method further includes determining whether a pull-down signal is present at the second node by comparing the reference value to a value of a signal present at the second node.