This paper describes an implementation of a 2-dimensional DCT processor and shows that the Globally Asynchronous Locally Synchronous (GALS) approach is highly suitable for implementation of such processors. Primarily the GALS approach increases the design efficiency by supporting the divide-and-conquer approach. The port controllers described uses standard cells to minimize the design effort wh...

In this paper, we propose a VLSI implementation method for one-dimensional discrete wavelet transform (1D-DWT) based on the GALS systems approach. An asynchronous wrapper, which includes two data communication ports and a local clock controller, is designed for the asynchronous data communication between the locally synchronous filtering modules in the wavelet filter bank. The detailed design m...

Digital systems commonly use a single global clock signal to synchronize the whole system. This is not always possible and it can be more advantageously to divide the system into separate clock domains, where each clock domain can operate with its own clock frequency. Communication between the different clock domains are not trivial and must be handled with care. Several schemes can be used dep...

Globally asynchronous locally synchronous (GALS) clocking applied to a system-on-a-chip (SoC) results in a design in which each core is a synchronous block (SB) of logic whose locally generated clock has an independent frequency and phase. Data is exchanged between cores using an asynchronous communication protocol. The nondeterministic synchronization strategies used by most GALS architectures...

A specific class of Petri nets was extended with AsynchronousChannels (ACs) and Time-Domains (TDs) to support Globally-Asynchronous Locally-Synchronous (GALS) systems’ modeling, analysis and implementation. This non-autonomous class of Petri nets is targeted to support the development of automation and embedded systems using a model-based development approach. It benefits from a tool chain fram...

A Gals (Globally Asynchronous Locally Synchronous) system typically consists of a collection of sequential, deterministic components that execute concurrently and communicate using slow or unreliable channels. This paper proposes a general approach for modelling and verifying Gals systems using a combination of synchronous languages (for the sequential components) and process calculi (for commu...

We read with interest the comprehensive review on rheumatoid arthritis (RA) in the kingdom of Saudi Arabia (KSA) by Almoallim and Alharbi.1 We would like to make a few comments. The best predictors for the development of RA, are anti-citrullinated protein antibodies (ACPA) and rheumatoid factors (RF), which can appear more than 10 years before clinical arthritis.2 Screening using ACPA and RF ar...