[phkahler]

I find the above pair of comments really interesting. I'm guessing there are parallels with differences of opinion and approach in other areas of engineering. There are always reasons for the differences, and those are usually rooted in more than just opinion or dogma.

In this case, I'd guess its got a lot to do with cost vs relevance of the simulation. If you're Intel or AMD making a processor, I bet FPGA versions of things are not terribly relevant because it doesn't capture a whole host of physical effects at the bleeding edge. OTOH for simpler designs on older processes, one might get a lot of less formal verification by demonstrating functionality on an FPGA. But this is speculation on my part.

[gluggymug]

"If you're Intel or AMD making a processor, I bet FPGA versions of things are not terribly relevant because it doesn't capture a whole host of physical effects at the bleeding edge."

Exactly. When you verify a design via an FPGA you are only essentially testing the RTL level for correctness. Once you synthesise for FPGA rather than the ASIC process, you diverge. In ASIC synthesis I have a lot more ability to meet timing constraints.

So given that FPGA validation only proves the RTL is working, ASIC projects don't focus on FPGA. We know we have to get back annotated gate level simulation test suite passing. This is a major milestone for any SoC project. So planning backwards from that point, we focus on building simulation testbenches that can work on both gate level and RTL.

I am not saying FPGAs are useless but they are not a major part of SoC work for a reason. Gate level simulation is a crucial part of the SoC design flow. All back end work is.

[dreamcompiler]

Let me try to summarize part of this: When you're building an ASIC, you have to care about the design at the transistor level because you're going for maximum density, maximum speed, high volume, and economies of scale. When you're building an FPGA, you are only allowed to care about the gates, which is one abstraction level higher than transistors.

In an FPGA, you cannot control individual transistors. (FPGAs build "gates" from transistors in a fundamentally different way than ASICs do, because the gates have to be reprogrammable.) And that's okay because FPGA designs aren't about the highest possible speed, highest density, highest volumes or lowest volume cost.