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Niko3's avatar
Niko3
Icon for Occasional Contributor rankOccasional Contributor
11 months ago
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deleting logic increases macrocells?

Hi, I have a very curious effect: The design of my project is a schematic for an EPM3064ATC100. After compilation 51 macrocells from 64 available ones are used. When I remove an AND with 4 inputs a...
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  • ShengN_altera's avatar
    ShengN_altera
    11 months ago

    Hi,


    This is possible behavior. The original 51 macrocells likely benefited from logic optimization which AND (4 inputs) and NAND (2 inputs) could have been part of a wider combinational logic structure, allowing the fitter to place more logic in fewer macrocells.

    When you removed those gates, the fitter had to restructure the logic, which could have increased the number of macrocells


    Thanks,

    Regards,

    Sheng


ShengN_altera's avatar
ShengN_altera
Icon for Super Contributor rankSuper Contributor
11 months ago

Hi,


This is possible behavior. The original 51 macrocells likely benefited from logic optimization which AND (4 inputs) and NAND (2 inputs) could have been part of a wider combinational logic structure, allowing the fitter to place more logic in fewer macrocells.

When you removed those gates, the fitter had to restructure the logic, which could have increased the number of macrocells


Thanks,

Regards,

Sheng