A simple data transfer technique using local address for networks-on-chips

Networks-on-chips (NoCs) have been studied to connect a number of modules in a chip by introducing a network structure which is similar to that in parallel computers. Since embedded streaming applications usually generate predictable small-sized data traffic, the network structure can be customized to the target traffic. Accordingly, we develop a data transfer technique for simplifying routers for predictable small-sized communication in simple tile-based architectures. A data structure is split into single-flit packets, and a label is attached to each of them in order to route them independently. A label is transferred on dedicated wires beside data lines in a channel by taking advantage of relaxed pin count limitations of a channel. To reduce the wiring area for the label, the label is locally assigned according to a preanalysis of required communication pairs of nodes. Analysis results show that only a 3-bit local label is sufficient to route all data of evaluated streaming applications in the case of a 16-node 2D torus. The required amount of hardware for a router is reduced by 37 percent compared with that for a wormhole packet router with the same number of routing table entries.