Globally-asynchronous locally-synchronous architectures to simplify the design of on-chip systems

Refinement-Based Formal Verification of Asynchronous Wrappers for Independently Clocked Domains in Systems on Chip

“…These concerns can be generally attributed to data and system safety issues. Although the simulations and tests reported in [8] and [9] show that their design works properly, such simulations and tests can only cover a small fraction of all possible configurations of relative delays in asynchronous communication, while we find that various malfunctions may still emerge under different relative delays. Applying formal verification, we find the potential pitfalls and provide delay constraints that permit to size the circuits so that the pitfalls are avoided.…”

“…In this paper, we: 1) propose new data transition model to represent the implicit relationship between clock and data validity events; 2) construct comprehensive implementation models for the asynchronous wrapper and the asynchronous communication scheme; 3) report several design pitfalls, including hazards in a design, obtained from 3D synthesizing tool, which claimed by [9] to be hazard-free; 4) provide relative timing constraints that were not mentioned by [8] and [9], along with fault diagnosis which indicates that the disregard of these constraints can cause system deadlock or erroneous data transfers.…”

“…Globally-asynchronous locally-synchronous architectures (GALS), proposed by [33], [8] and [9] among others, show that a system can be partitioned into several independently clocked domains (subsystems) that communicate in a self-timed manner. To isolate each locally-synchronous domain from its globally-asynchronous environment, [1], [8] and [9] introduced an elegant design, called asynchronous wrapper, used to equip each locally-synchronous domain.…”

“…To isolate each locally-synchronous domain from its globally-asynchronous environment, [1], [8] and [9] introduced an elegant design, called asynchronous wrapper, used to equip each locally-synchronous domain. Asynchronous wrappers serve as controllers for data transfer between individual domains, and deliver a locally generated pausible clock for the synchronous part of circuitry [8].…”

An asynchronous GALS interface with applications

“…This is not the first GALS interface to have been designed. Examples of others are found in [4] and [5]. The most important difference between the interface presented here and others in the literature is that this one does not require the interface to control the local clock signals, whereas the others require a "stoppable clock".…”