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Altera_Forum's avatar
Altera_Forum
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16 years ago

FFT Megacore resource usage different between software and user guide

Dear all, I post a message because I have some trouble with the resource usage of the FFT MegaCore function. I follow the procedure described in user guide (p 2-1 -> 2-7) to evaluate resource u...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

i would say there may be a bug in the MegaWizard and the ALUTs and MULTs are off by a factor of 2.

i did a 4096-point 16-bit streaming FFT on Stratix III with all other settings as default. MULTs are estimated at 48 but are actually 24 after the mapper. LUTs are estimated at 6077 but are 3770 after the mapper.

i know the resource estimator is not supposed to be 100% accurate but there is probably a bug in the math somewhere.