Hi there!
I am wondering what the default IOSTANDARD is on pins for which it is not explicitly assigned in the UCF of the project. Here, the project uses LVCMOS25 for some pins where nothing is set explicitly - is that always the default value? Is it a good style to always define the IOSTANDARD in any case?
Thanks for any hints, Torsten
Yes, the default is LVCMOS25. I always specify the IOSTANDARD, but I usually don't use LVCMOS25.
Thanks! Did you get that information from the documentation? I did not find it when I tried.
BTW: Is there a way to add a CONFIG STEPPING directive to the generated .ucf file from a .xbd file? Anyone? ;-)
Greetings, Torsten
Just from experience.
May I recommend ALWAYS specifying the defaults? The designer should know what the IOSTANDARD and other attributes should be for each port, and should not rely on the tools for a default. What if the software were to change the defaults?
No "what if" about it - ISE did exactly that sometime around 5.1 (+/-
1 :-) I now always specify my IOSTANDARD.Marc
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