Single wire serial interface

Abstract

A single wire serial interface for power ICs and other devices is provided. To use the interface, a device is configured to include an EN/SET input pin. A counter within the device counts clock pulses sent to the EN/SET input pin. The output of the counter is passed to a ROM or other decoder circuit. The ROM selects an operational state for the device that corresponds to the value of the counter. In this way, control states may be selected for the device by sending corresponding clock pulses to the EN/SET pin. Holding the EN/SET pin high causes the device to maintain its operational state. Holding the EN/SET pin low for a predetermined timeout period resets the counter and causes the device to adopt a predetermined configuration (such as off) until new clock pulses are received at the EN/SET pin.

What is claimed is: 
     
         1 . An interface for controlling a device, the interface comprising:
 a first circuit for accumulating a count of clock pulses encoded in a received signal;   a second circuit for mapping the count of clock pulses into a corresponding control state for the device; and   a third circuit for resetting the count of clock pulses to zero if the received signal is low for a period that exceeds a predetermined timeout value.