Fight Club: Automated vs. Hand Crafted PinMultiplexing

blogs.synopsys.com /breakingthethreelaws/2015/02/fight-club-automated-vs-hand-crafted-pin-multiplexing/

Posted by Michael Posner on February 27th, 2015

This week a prototypingengineer challenged me thathis customized and handcrafted pin multiplexingcapability was better than theHAPS High Speed Time-Domain Multiplexing, HSTDM.My response, Faster, maybe,better NO. This blog explainswhy the HAPS HSTDMcapability will beat out acustom coded multiplexingcapability hands down everytime.

First lets list of the positivesand negatives of a customcoded pin multiplexingcapability

Positives

Its tailored to the exact design requirementsIts tuned for a specific set of FPGA pins and inter-FPGA connections to push performance to thelimits

Negatives

Its hand crafted meaning effort to developIt has to be manually inserted into the designIt breaks if the design requirements changeIts tuned so will need to be customized to different FPGA pins and inter-FPGA connectionsMight be unreliable leading to mystery ghost bugs to chase down

I am sure the list of negatives is longer but I would bet that you already get the idea. While its possible tocraft a pin-multiplexing block that eeks out every possible drip of performance the overhead of insertion,modification to different design and hardware requirements and testing makes it inferior to the HAPSHSTDM capability.

HAPSHSTDM wasdesigned todeliver anautomated,cycleaccurate,highest

performance, reliable, modular and scalable pin multiplexing solution for the HAPS systems. Automatedinsertion through ProtoCompiler ensures that the usage is as unobtrusive as possible. HAPS HSTDM istested to run on every qualified IO pin across the HAPS-70 system. It will reliably run on any HAPSplatform, we can claim this as the HAPS hardware itself is performance tested as part of the productionmanufacturing tests ensuring that all systems and interconnects meet the minimum required performancefor HSTDM operation. It supports multiple ratios meeting the need of many different design requirements.It is very high performance using the latest differential signaling and training techniques with built in errordetection. Just looking at this list its clear that HAPS HSTDM has many advantages over custom.

But wait, there is more. I would challenge that using the flexible capabilities of the HAPS hardwareinterconnect combined with the HAPS HSTDM capabilities that the overall HAPS prototype will run at ahigher system performance. Ive talked about this capabilities a couple of times. The HAPS systems do nothave any dedicated PCB traces between FPGAs. All interconnect is done via intelligent cabling. Thismethod enables the HAPS hardware to be customized to better match the DUTs interconnect needs. Thismeans you can create more interconnect density where the DUT needs it. More dense interconnect canhelp reduce the overall pin multiplexing ratio required resulting in higher performance system operation.Remember your prototype is only as fast as the slowest link.

This HAPSflexibleinterconnectcombinedwith theHAPSHSTDMautomatedanddeployed by

ProtoCompiler is a very powerful solution and this is why I claim that its better than a hand craftedscheme.

Do youagree?

Fight Club: Automated vs. Hand Crafted Pin Multiplexing