Towards reliable 5Gbps wave-pipelined and 3Gbps surfing interconnect in 65nm FPGAs

ABSTRACT

FPGA user clocks are slow enough that only a fraction of the interconnect's bandwidth is actually used. There may be an opportunity to use throughput-oriented interconnect to decrease routing congestion and wire area using on-chip serial signaling, especially for datapath designs which operate on words instead of bits. To do so, these links must operate reliably at very high bit rates. We compare wave pipelining and surfing source-synchronous schemes in the presence of power supply and crosstalk noise. In particular, supply noise is a critical modeling challenge; better models are needed for FPGA power grids. Our results show that wave pipelining can operate at rates as high as 5Gbps for short links, but it is very sensitive to noise in longer links and must run much slower to be reliable. In contrast, surfing achieves a stable operating bit rate of 3Gbps and is relatively insensitive to noise.

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.8 Performance and Reliability
      B.8.0 General

Additional Classification:
  C. Computer Systems Organization
  C.5 COMPUTER SYSTEM IMPLEMENTATION
      C.5.4 VLSI Systems

General Terms:
Design, Performance, Reliability

Keywords:
bit-serial, fpga, interconnect, network-on-chip, on-chip serdes, programmable, reliable, surfing, wave pipelining