A Novel Stretchable Clock Based Communication Port Controller for GALS Pipeline Systems

The GALS (Globally Asynchronous Locally Synchronous) paradigm is a promising alternative to implement SoC (Systems-on-Chip). GALS systems are formed by synchronous modules that operate with unrelated clock signals and interact with self-timed communication. An asynchronous wrapper is generated for each synchronous module, where a clock generator and communication ports (asynchronous channels) are inserted. Two criticisms of GALS systems based on the asynchronous wrapper are the cost of communication and metastability. In this paper, we propose a new asynchronous wrapper geared towards the GALS pipeline. Compared to asynchronous wrappers from the literature, it reduces communication cost and area reduction and is free of metastability. Our wrapper's main feature is a new controller port that performs the two-phase protocol's input/ output communication functions and generates the stretchable clock signal.