pullup in Xilinx ISE 10.1

I tried building a small project in ISE 10.1 using the CoolRunner II CPLD XC2C128 and ran into a problem with pullups. I defined a few inputs with pullup in the UCF file, and the mapper complained about a conflict between keeper and pullup on the same pin. I had to set unused pins and inputs to default to pullup to get rid of the error, otherwise I just got the keeper and no pullup. it seems the ucf command for pullup isn't being obeyed. Is the CoolRunner II only able to have pullups if they are used on all (input) pins?

Thanks,

Jon

Reply to
Jon Elson
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Yup, that's it, now I remember seeing that in the data sheet, not very boldly described, either. The selection of keeper or pullup/pulldown is a GLOBAL option for all inputs. Well, at least what I saw was consistent with the docs.

Jon

Reply to
Jon Elson

You can select whether you have any termination on a pin-by-pin basis, but for those pins that have termination, it must be the same. So in effect pullup vs. keeper vs. pulldown is global, but any of these vs. tristate is available on a pin-by-pin basis.

-- Gabor

Reply to
Gabor

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