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AR# 12209

10.1i Virtex-II MAP - The IOB packer fails to use unbonded pads as instructed by the LOC=UNBXX constraint


I am attempting to use the registers in unbonded IOBs by assigning a LOC attribute to the register in the form of:


However, this leads to the following error:

"ERROR:Pack:18 - The design is too large for the given device and package. Please check the Design Summary section to see which resource requirement for your design exceeds the resources available in the device."

The following resource summary is given:

Number of bonded IOBs: 93 out of 88 - 105%


This problem is not scheduled to be fixed. The use of registers in unbonded IOBs is not supported except by using hard macros to bypass this IOB packing limitation.
AR# 12209
Date Created 08/29/2007
Last Updated 12/15/2012
Status Active
Type General Article
  • Virtex-II