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Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

problem in Fitter

Hi,

I am using Quartus 9.1 Service Pack 1 Web Edition.

The device is Cyclone III, EP3C16E144I7

The summary of my design is :

Total logic elements 15338/15408 (100%)

Total combinational functions 15204/15408 (99%)

Dedicated logic registers 7999/15408 (52%)

But the Fiiter is not successful, which says:

Fitter requires 966 LABs to implement the project, but the device contains only 963 LABs.

Why is that? From the summary, it seems I have not exceeded the capacity of the device. What is the relation between logic elements and LABs?

Thank you!

1 Reply

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Basically the LAB's are a routing resource for interconnection that you have over-utilized.

    Typically, when you are not 100% full, it can also use LE's for routing, but in your case, you have already used almost all the LE's. Try moving some of you logic to ram blocks if you can.

    or reducing the design by optimizing for area versus speed. Or remove non-critical logic.

    Pete