Answers Database

XC3000/XC4000: Are the internal tri-state busses(3k,4k) PULLED Up by default?


Record #1423

Product Family:  Software

Product Line:  FPGA Core

Problem Title:
XC3000/XC4000: Are the internal tri-state busses(3k,4k) PULLED Up by
default?



Problem Description:
Keywords: Tristate, BUFT, BUFE, XC3000, XC4000

Urgency: Standard


Description
Internal tri-state bus for 3k and 4k families does not have
pullups on the outputs by default.


Solution 1:

For a schematics based design, connect a PULLUP symbol on the
outputs of the internal tri-state bus.
For a behavioral design, instantiate a PULLUP primitive.
Refer to the appropriate Interface Guide for more information.



End of Record #1423