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XC4000XLT: Should the Vtt Pins be prohibited when using an XLT part?
Keywords: xlt, prohibit, vtt, ucf
General Description: Should the Vtt pins on XLT parts be "PROHIBITED"
from use by constraining them?
Absolutely. The UCF files supplied with the LogiCORE PCI32 4000
for XLT devices already use this constraint.