Implementation of Parallel LFSR-based Applications on an Adaptive DSP featuring a Pipelined Configurable Gate Array

Linear feedback shift registers (LFSRs) are common structures in many application fields, including cryptography, digital broadcasting and communication. High-throughput requirements need highly parallel implementations, usually accomplished in state of the art system on chips (SoCs) with application specific coprocessors. Although this approach achieves the required performance, it rapidly shows lack of flexibility when those devices are proposed, as an example, for multi-standard modems or for security applications in which run-time update can provide added value. This paper shows the implementation of parallel LFSR-based applications on an embedded adaptive DSP featuring a Pipelined Configurable Gate Array (PiCoGA). With respect to standard embedded FPGAs, pipelined devices usually provide better performance, e.g. in terms of speed, but they commonly show the undeniable drawback of additional design constraints. As a test-case, we consider the implementation of the 32-bit CRC used in the Ethernet standard that achieves on the target architecture up to similar to 25Gbit/sec throughput, with a parallel LFSR processing 128 bit at time, which is comparable to the performance offered by some ASIC devices.