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t_alars's avatar
t_alars
Icon for New Contributor rankNew Contributor
2 years ago
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Logic elements utilization in FPGA

Hello All, I have an old design on cyclone 3 with Quartus 10 and the used logic elements (in ALMs) are 20k. Now, I migrate exactly the same design to Quartus 21 also I changed the FPGA to Cyclone V...
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  • Nurina's avatar
    Nurina
    2 years ago

    Hi Taha,


    Yes, with a large software jump I would expect differences in the project. Be it ALM usage or place & route or timing performance.

    This is because as the Quartus versions change the optimization algorithm also changes.


    I would suggest to also check for nodes that have been synthesized away. If your design is small enough, you can see it in the netlist viewers. It is easier to check in the warning messages too. Check for the below warning message

    "Warning (14320): Synthesized away node"


    Regards,

    Nurina


Nurina's avatar
Nurina
Icon for Regular Contributor rankRegular Contributor
2 years ago

I'm not entirely sure. Have you checked for any logic/register that have been synthesized away? Is the design working as expected in simulation and hardware tests?


Regards,

Nurina


  • t_alars's avatar
    t_alars
    Icon for New Contributor rankNew Contributor
    2 years ago

    Thank you for quick reply @Nurina .

    The total registers drop from 10k to 7k. I am still facing some issues with the testing however, I just want to know if I can consider this drop as normal.

    Sure later on with simulation and test i will get the correct answer.

    But for know, is this might be normal cuz we have 11 years gap between the Quartus version and the fpga used?

    Cheers,

    Taha