Are VHDL post-93 versions used in real life?
I've just finished implementing VHDL protected types, as defined in the VHDL 2000 standard.
As part of our quality assurance process, we run a bunch of VHDL code through our tool. In fact, we've downloaded all freely available VHDL from the internet to stress test our tool. However, none of these projects seem to use protected types. All I can do is run the tests that I have created and compile the VHDL files that one of our users has sent me.
This makes me wonder if the world will ever upgrade from VHDL-93? It has been seventeen years since that standard was approved. Pretty soon, we will start training engineers that were not even born in 1993!
My hypothesis is that engineers won't use more recent standards because EDA companies won't implement them and EDA companies are not interested because their customers don't use the newer standards. The Wikipedia contains a list of simulators with information on which VHDL version is supported. If this list is correct about half of the simulators support VHDL-93. The other half supports VHDL-2002. Never mind VHDL-2008, for which I have the language reference manual lying on my desk. Now I know that Wikipedia might or might not be accurate: if you see any errors in Wikipedia, please update that wiki page.
As an interesting note, the documentation for Xilinx ISim states that their mode for VHDL-200X "provides support for select additional constructs introduced post-VHDL-93." That is exactly what we support: select additional constructs. However, this is a temporary situation. Eventually all EDA providers should strive to support the latest standards in full. What else are standards for? (Which reminds me I should get a copy of Karen Bartleson's book on Effective Standards.)
Anyway, here are two questions for all of you:
- Which VHDL standard do you use? (and why)
- If you have any VHDL-2002 or VHDL-2008 lying around that you can share, please do. It would be great for our quality assurance and for proving to the world that recent VHDL standards are useful after all.
-- Philippe
Comments
Hi, IMHO the question is more
Hi,
IMHO the question is more which version of VHDL do you use for the design itself and for the testbench.
Even the small part of the 2008 VHDL standard at this moment implemented in Modelsim is already nice to use at the testbench level.
Finally it's possible to stop the test without an "Error: this is not an error" message. @check The stop and finish procedure
The hierarchical names (e.g. << signal .tb.uut.o_n : std_logic >> ) works to probe signals into the design. No NcMirror or other simulator depending code is needed anymore.
jan,
I would like to reiterate the
I would like to reiterate the previous comment. The reason that full VHDL 2008 features are not used in the real world is because the tool vendors refuse to support these features. I believe a more active community would follow VHDL if the tool vendors supported it better. It feels like every time you write something clever or abstracted you run into a need for VHDL 2008 or the tool balks for some other strange reason.
I have requested numerous times that Synopsys, Altera, Xilinx, Mentor, and Aldec work to implement support for the standard fully. Each time I am asked to provide a list of the priority for each feature. My reply to this is that I would like full support of the standard as soon as possible. VHDL 2008 was well thought out by the standard team and each feature has a definite and useful purpose.
I would encourage all active VHDL designers to hammer on these tool vendors and demand full support for this standard as soon as possible.
Sigasi is a good tool and should strive to fully support the standard. The problem of tool choice is exacerbated by the fact that I must have full support of a feature by both my simulation and synthesis vendor in order to use it. Sigasi should work to not add to this problem.
Since many people are
Since many people are interested in having these post-93 features, I started a new thread to ask which features are used and which features are desired.
http://www.sigasi.com/forum/which-vhdl-20022008-features-do-you-need
I am using VHDL-93 because I
I am using VHDL-93 because I am a beginner.
Also I think vhdl-200x is not fully supported by all tools. So I didnt want to take any risk getting an error message after completing the code..
--vipin
http://vhdlguru.blogspot.com/
Also, there is no clear
Also, there is no clear definition stating the difference between the VHDL standards (Atleast in open source!!!).
Hi There, The difference
Hi There,
The difference between successive versions is defined by the IEEE-1076 standards. You can buy the standardisation documents from IEEE. People have written books about each version of VHDL, including a book specifically about the latest standard. In addition, Doulos does a great job at explaining the new VHDL standards on their website.
I have found VHDL 2008 has
I have found VHDL 2008 has several good features which are now currently supported in Altera Quartus. Not all the VHDL 2008 features, but several of them. I use Active HDL from Aldec and to the best of my knowledge all the features of VHDL2008 are supported. Aldec seems to be out in front of the other EDA companies in this regard. I will submit a question to Altera technical support and ask them what their roadmap is for supporting all of the VHDL2008 features. -James