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Altera_Forum's avatar
Altera_Forum
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8 years ago

Maximum inputs per LAB

Can't find this documented anywhere. Is there a cap on the total number of signals that can be routed into a single LAB? Take Cyclone V, to be specific. From the datasheets, I was under the imp...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
8 years ago

Failing paths differ with every run. The one commonality is routing overload. The entire area where pipeline stages sit is bright red in the "routing hotspots" view. And it is difficult to optimize the design if you don't know the limitations of the hardware. If there is indeed an undocumented limit on the number of inputs per LAB, I could at least try to rework the algorithm to reflect that constraint.