Constraints learning materials

[pavel.m]

Hello,

I'm new in FPGA world. I read some VHDL books and I can create not muc
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 us
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]

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 t
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?



---------------------------------------
Posted through http://www.FPGARelated.com

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

---------------------------------------
Posted through http://www.FPGARelated.com

 

[Gabor]

pavel.m wrote:

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?



---------------------------------------
Posted through http://www.FPGARelated.com


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.

---------------------------------------
Posted through http://www.FPGARelated.com

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

 

[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

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 coul
see that it works only with constraints?

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