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How to fiix LUT inputs?

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d0nathan

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I implemented ring oscillators on an Altera Cyclone IV with Quartus II.

The compilation choses arbitrarily which inputs of the LUTs are used.
I could edit each LUT seperatly but this is very time-consuming.

Is there a way to determine which LUT inputs are used without changing each one severally?
 

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TrickyDicky

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Unfortunately, the only way to do this is but hand editing each lut. The tools are not really meant for this kind of logic.
 

ads-ee

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Instantiate the LUTs using library primitives. I don't recall either Xilinx or Altera swapping pins when you instantiate a LUT.
 

FvM

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When using cyclonexx_lcell_comb, the inputs may be reassigned by the fitter. As far as I understand, this done due to routing constraints, the routing options aren't orthogonal.
 

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