The Argo NOC: Combining TDM and GALS

Argo is a network-on-chip developed for use in a multi-core platform designed specifically for hard real-time applications and it supports message passing across virtual end-to-end channels. Argo implements these channels using time-division-multiplexing (TDM) of the resources in the NOC following a static schedule. This requires some form of global synchrony across the platform. At the same time it is generally accepted that a large chip should employ some form of globally-asynchronous locally-synchronous (GALS) organization. By using asynchronous routers and by rethinking the microarchitecture of the network interfaces we have managed to combine TDM and GALS and obtain a very hardware-efficient implementation of the NOC. The paper gives a brief overview of the Argo NOC and focuses on two important issues: how to safely bring the NOC out of reset and timing analysis of the network of asynchronous routers.