Circuit for interfacing asynchronous to synchronous communications

Abstract

An Asynchronous Communications Interface to Synchronous Circuit having three stages is disclosed. The first stage captures the control and data signals from an asynchronous bus and converts them into signals which are synchronous to the internal clocks of the interface chip. The second stage of the interface is a synchronous state machine which utilizes the synchronized signals generated by the first stage to determine the current state of the asynchronous bus. The third stage of the interface uses the data generated by the synchronous state machine and the control and data signal capture logic to validate the data in a synchronous manner. This allows further processing of the data from the asynchronous bus without the use of any further asynchronous logic or timing.