TBUF with black boxes


I am writing VHDL and attempting to use the precompiled functions: okHostInterface, okWireIn, and okWireOut and having some issues during synthesis:

XST:2183 - the following tristate(s) are NOT replaced by logic (Please refer to Answer Record 20048 for more information): ti_data, ti_data, ti_data, etc…

looking at Xilinx’s Answer Record 20048: one situation where XST is not able to replace a tristate by logic is when the tristate is connected to a black box.

Synthesis is also telling me that More than 100% of Device resources are used because I’m using 48 out of 0 TBUFs.

Is there anything I can do about any of these things so I can make this work?
a) ti_data is a tristate
b) it is connected to a black box
c) therefore it cannot be replaced by logic (ie needs a TBUF)
d) there are 0 TBUFs available to me (3s1500fg320-4)



Hi Ryan-

These should be only warnings and can safely be ignored. They will be replaced by logic at a later stage when the logic from the black boxes becomes available. They end up becoming MUXes.

Are you having a problem where synthesis is actually failing from these? If so, can you include the full text from synthesis?



Sounds like you are trying to get the ngc files to work under EDK?

I have a support case going on with Xilinx about this… Works for ISE not for EDK… my FAE is telling me that this is because the MHS MPD [parse?] rules do not allow for tri-state. I think Xilinx has a bug they need to fix…

Still Waiting on Xilinx,