I spoke with Todd Westerhoff of SiSoft about their new Virtual Prototype Analysis that can simulate large systems with thousands of serial links at DesignCon 2012. You can see the video interview here and below is a short description and link to a technical paper that described the analysis of such a large system.
While not long ago systems had only several serial links, it’s now becoming common for systems to include hundreds – and even thousands – of such links. This paper describes the development and analysis of a large system with thousands of serial links. Due to the system’s size and complexity, the design team invested in a multi-year effort to build and qualify a virtual environment capable of both verifying connectivity and simulating any and all of the channels. Problematic channels with incomplete system-level connections, poor eye openings, or high BER are quickly identified. Performance limiters such as inherent discontinuities (and their associated resonances), and Tx/Rx equalization imbalance are found and examined in detail. The virtual system is also used to guide design choices such as layer stacking, via construction, back-drilling, and trace/connector impedances. Processes to optimize and select equalization choices are also described.