Apple Inc.
General purpose input/output with hysteresis

Abstract:

In an embodiment, an integrated circuit includes one or more GPIO pins coupled to a GPIO block in the integrated circuit. At least a first GPIO pin may include corresponding logic circuitry that may be programmed to apply one or more requirements to changes of the digital value received on the first GPIO pin before the change is forwarded to a destination within the integrated circuit. That is, if the requirements are not met for a given change, the logic circuitry may suppress the given change so that it is not provided to other circuits internal to the integrated circuit (e.g. the destination circuit that receives communication via the GPIO pins). The one or more requirements may be a form of hysteresis, for example.