What technology SoC engineers need for next-gen chips?

About 318 engineers and managers completed a blind, anonymous survey on 'On-Chip Communications Networks (OCCN), also referred to as an “on-chip networks”, defined as the entire interconnect fabric for an SoC. The on-chip communications network report was done by Sonics Inc. A summary of some of the highlights is as follows.

The average estimated time spent on designing, modifying and/or verifying on-chip communications networks was 28 percent (for the respondents that knew their estimate time).

The two biggest challenges for implementing OCCNs were meeting product specifications and balancing frequency, latency and throughput. Second tier challenges were integrating IP elements/sub-systems and getting timing closure.

As for 2013 SoC design expectations, a majority of respondents are targeting a core speed of at least 1 GHz for SoCs design starts within the next 12 months, based on those respondents that knew their target core speeds. Forty percent of respondents expect to have 2-5 power domain partitions for their next SoC design.

A variety of topologies are being considered for respondents’ next on-chip communications networks, including NoCs (half), followed by crossbars, multi-layer bus matrices and peripheral interconnects; respondents that knew their plans here, were seriously considering an average of 1.7 different topologies.

Twenty percent of respondents stated they already had a commercial Network-on-Chip (NoC) implemented or plan to implement one in the next 12 months, while over a quarter plan to evaluate a NoC over the next 12 months. A NoC was defined as a configurable network interconnect that packetizes address/data for multicore SoCs.

For respondents who had an opinion when commercial Networks-on-Chip became an important consideration versus internal development when implementing an SoC, 43 percent said they would consider commercial NoCs at 10 or fewer cores; approximately two-thirds said they would consider commercial NoCs at 20 or fewer cores.

The survey participants’ top three criteria for selecting a Network on Chip were: scalability-adaptability, quality of service and system verification, followed by layout friendly, support for power domain partitioning. Half of respondents saw reduced wiring congestion as the primary reason to use virtual channels, followed by increased throughput and meeting system concurrency with limited bandwidth.