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Which Simulators

I'm sure this kind of things has come up in the past, but given that things change, I'd like to throw this out there.

Which simulators do people like to use for their HDL purposes?

I have tried a couple of simulators and I was curious about peoples recommendations.

I have used Modelsim XE starter for my purposes (I am just a hobbyest now), icarus verilog and GPL cver. I have used the built-in quartus simulator as well.

So a couple questions regarding these. Which simulators do people consider feature complete? Why do I never hear about cver in this group? Does nobody use it? If not, why? What's really wrong with Modelsim. People seem faily opposed to it. They say the error messages are bad, but I certainly feel that icarus error messages are worse.

Also, I haven't really discussed VHDL. Which are best for this? I've heard GHDL is pretty good.

I've mostly discussed free simulators, but I'm also interested in how expensive simulators compare to the free sims.

-Arlen

Reply to
gallen
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-- Mike Treseler

Reply to
Mike Treseler

I would concur. We do exactly the same with a combination of licenses from these two vendors. ActiveHDL is very good at sorting file order out automatically and has in-built libraries that you don't need to compile to get going. The detachable waveform windows are very nice especially when you run multi-monitor machines like we do at Enterpoint. The cut and paste between these windows is also useful.

In the last couple of years Mentor have improved the user interface of Modelsim and I hope they will continue the trend. I think they got a bit complacent. Five years ago I would have said Modelsim was the best but now I'm not so sure.

Both these companies give out evaluation licenses so go try them out and see which you like best.

John Adair Enterpoint Ltd. - Home of Broaddown2. The Ultimate Spartan3 Development Board.

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Reply to
John Adair

I use a combination of Aldec and Modelsim PE. Aldec is more user friendly and is really a complete design entry suite where Modelsim is a simulator. I prefer Aldec for ease of use. Some customers insist on Modelsim, so I have it. Modelsim is about the fussiest VHDL parser you'll find, and it is absolutely true to the LRM, so it does serve as a decent VHDL code check to make sure you aren't doing something that is slipping past your other tools but might get you in trouble down the road. It is also useful to run on a second machine while I'm, doing more design entry on Aldec. If I were to buy just one, my choice would be Aldec for the more complete design entry suite, the better customer support and the lower price.

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--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930     Fax 401/884-7950
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Reply to
Ray Andraka

I've been using GHDL quite a lot lately.

I'm not sure how 'feature complete' GHDL is (if you define 'feature complete' to mean language features). I haven't run into any problems lately (I'm currently using the latest 0.18 release), but that doesn't mean that problems don't exist.

If you count a frontend GUI as part of being 'feature complete' then it's probably not what you're looking for. Personally, for my useage, a GUI often gets in the way. I prefer to write scripts or Makefiles to compile/simulate my designs, though, so for me it's a feature. Also, I've been doing some mixed-language modelling (part of my algorithm is writen in C and part in VHDL, the two communicate via pipes) so the fact that GHDL is just another frontend to GCC is a big plus since it's easy to write foreign models in C and link them to the testbench. The open source nature of GHDL is helpful for this mixed-language approach since I can always look at the source to figure out some of its internals if need be.

The author of GHDL readily admits that it's not as fast as Modelsim (used to be considered the fastest VHDL simulator - is it still?). But GHDL is free, so if you have a cluster of machines simulating your designs you don't need to buy a license for each machine. And since PCs running Linux are way cheaper than ModelSim licenses, if you need better performance you can just add more PCs to your cluster. Also, I suspect that there is still a lot of room for performance improvements in GHDL - the author has been concentrating on features and bug fixes so far; he has said that he would concentrate more on performance later.

Phil

Reply to
Phil Tomson

I think the best commercial simulator is by far Cadence's ncsim. This can support verilog or vhdl or both. I know it is relatively new to the FPGA simulation world, but is supported in Xilinx's ISE now. I have used it extensively for verilog HDL development, and found it extremely fast, has good, intelligent syntax/error messages, and a fantastic GUI (modelsim's gui really gets on my nerves!). (it also allows features such as tracing the source of an X on a net (schematically), which is not one I have seen in other simulators. I dont know if it is faster than modelsim, (I've never compared them) but it definatly feels slicker. As for feature complete - I'm guessing you mean language coverage? - I dont know about VHDL, but I always code in verilog-2001, and have never seen it unable to handle these "new" constructs. I've tried ModelSim, Virsim, Verilog-XL, ncsim (ncverilog), and without doubt ncverilog wins. It does take a little getting used to, but it's more than worth it!

gallen wrote:

I've

Reply to
John McGrath

Which version of Modelsim? There is a feature in (or available for) SE that lets you chase down those X's.

Sorry, I haven't used ncsim. (Years ago, I did use something from them. It's been so long, I don't remember much about it.)

Jason

Reply to
jtw

Hi, I saw your post about ncsim. I was used to modelsim and really liked it but I have to use ncsim now. I wonder how you use it. You say the GUI is very good, so I wonder how you launch it and run it. I assume you launch it from the command line. What arguments are you using? It would help me if you can simply give me a general idea of your flow.

Thank you very much, David

John McGrath wrote:

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Reply to
gretzteam

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