TBUF with black boxes

Spartan-3 USB 2.0 Modules
1

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)

Thanks,
Ryan

2

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?

3

Hello,

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,

Bill