The Price of Routing in FPGAs

Among integrated circuits, field programmable gate arrays (FPGAs) may be the most spectacular benefactors of the steady progress of very large scale integration (VLSI) technology in the last two decades: current FPGA chips offer up to one million programmable gates. A close look at recent families of mainstream FPGAs, however, shows that the amount of silicon dedicated to routing increases much faster than that devoted to the gates themselves. The main reason for this is the fact that the routing needs to be reconfigurable. A simple quantitative analysis shows that this trend, if pursued, will lead to a widening gap between FPGA performance and full-cust- om VLSI performance. Some prospective solutions to this problem are exposed and discussed

The Price of Routing in FPGAs

Among integrated circuits, field programmable gate arrays (FPGAs) may be the most spectacular benefactors of the steady progress of very large scale integration (VLSI) technology in the last two decades: current FPGA chips offer up to one million programmable gates. A close look at recent families of mainstream FPGAs, however, shows that the amount of silicon dedicated to routing increases much faster than that devoted to the gates themselves. The main reason for this is the fact that the routing needs to be reconfigurable. A simple quantitative analysis shows that this trend, if pursued, will lead to a widening gap between FPGA performance and full-cust- om VLSI performance. Some prospective solutions to this problem are exposed and discussed

Programmable photonics : an opportunity for an accessible large-volume PIC ecosystem

We look at the opportunities presented by the new concepts of generic programmable photonic integrated circuits (PIC) to deploy photonics on a larger scale. Programmable PICs consist of waveguide meshes of tunable couplers and phase shifters that can be reconfigured in software to define diverse functions and arbitrary connectivity between the input and output ports. Off-the-shelf programmable PICs can dramatically shorten the development time and deployment costs of new photonic products, as they bypass the design-fabrication cycle of a custom PIC. These chips, which actually consist of an entire technology stack of photonics, electronics packaging and software, can potentially be manufactured cheaper and in larger volumes than application-specific PICs. We look into the technology requirements of these generic programmable PICs and discuss the economy of scale. Finally, we make a qualitative analysis of the possible application spaces where generic programmable PICs can play an enabling role, especially to companies who do not have an in-depth background in PIC technology

A Scalable Correlator Architecture Based on Modular FPGA Hardware, Reuseable Gateware, and Data Packetization

A new generation of radio telescopes is achieving unprecedented levels of sensitivity and resolution, as well as increased agility and field-of-view, by employing high-performance digital signal processing hardware to phase and correlate large numbers of antennas. The computational demands of these imaging systems scale in proportion to BMN^2, where B is the signal bandwidth, M is the number of independent beams, and N is the number of antennas. The specifications of many new arrays lead to demands in excess of tens of PetaOps per second. To meet this challenge, we have developed a general purpose correlator architecture using standard 10-Gbit Ethernet switches to pass data between flexible hardware modules containing Field Programmable Gate Array (FPGA) chips. These chips are programmed using open-source signal processing libraries we have developed to be flexible, scalable, and chip-independent. This work reduces the time and cost of implementing a wide range of signal processing systems, with correlators foremost among them,and facilitates upgrading to new generations of processing technology. We present several correlator deployments, including a 16-antenna, 200-MHz bandwidth, 4-bit, full Stokes parameter application deployed on the Precision Array for Probing the Epoch of Reionization.Comment: Accepted to Publications of the Astronomy Society of the Pacific. 31 pages. v2: corrected typo, v3: corrected Fig. 1