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Constraints learning materials

Hello,

I'm new in FPGA world. I read some VHDL books and I can create not much advanced, but working projects. Most of my designs I tested on Spartan3. And the only constraints I always use are LOC to assign pins.

It works, but I know that in more advanced projects it is necessary to use other constraints. I read Xilinx tutorials, but don't feel it from them.

I'm trying to find something where it is explained on some real examples, maybe some examples with growing level of difficulty.

Do you know some book, pdf, website?

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pavel.m
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I checked on Linux and Windows, on different browsers and see that my post's lines aren't wrapped. Sorry for that, don't know why.

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Reply to
pavel.m

Did you look at the Xilinx user forum. There is a Blog section and in there is a 5-part (IIRC) series of articles about timing constraints. I definitely agree that the Constraints Guide is very hard to use, mostly because the "examples" don't show a complete constraint, but rather a strange BNF-like definition of the constraint syntax. I find that I very often look through UCF files of old projects to see how the constraint is actually defined.

You could of course use the constraints editor from the Xilinx GUI, but I've found that it tends to trash my UCF files, so I generally stay away from it.

-- Gabor

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Gabor

That looks very useful. I have to read and understand it. Thank you. Maybe you have some idea how to create not complex example where I could see that it works only with constraints?

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pavel.m

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