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Altera_Forum
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13 years ago

What is mean of timing model in EDA Gate Level Simulation?

When I use ModelSim-Altera to do simulation, I run modelsim from Quartus II using Tool-> Run EDA Simulation Tool -> EDA Gate Level Simulation. Then there are three options:

Slow-81.2V 85 Model

Slow-81.2V 0 Model

Fast-M 1.2V 0 Model

I just wonder what is difference between them and how can I decide which one I should use?

Thanks very much.

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    --- Quote Start ---

    When I use ModelSim-Altera to do simulation, I run modelsim from Quartus II using Tool-> Run EDA Simulation Tool -> EDA Gate Level Simulation. Then there are three options:

    Slow-81.2V 85 Model

    Slow-81.2V 0 Model

    Fast-M 1.2V 0 Model

    I just wonder what is difference between them and how can I decide which one I should use?

    --- Quote End ---

    All three.

    Your systems should be designed to be robust over all process, voltage, and temperature variation (also known as PVT).

    http://en.wikipedia.org/wiki/process_corners

    These three timing models are different PVT setups.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    Thanks very much, Dave! I will read the link you give. And do you know can we estimate the power consumption of our design in Quartus II after completed compilation?

    Thanks!
  • Altera_Forum's avatar
    Altera_Forum
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    --- Quote Start ---

    And do you know can we estimate the power consumption of our design in Quartus II after completed compilation?

    --- Quote End ---

    You write a testbench that enables the design as you intend to use it, i.e., with realistic traffic on its I/Os, and realistic processing using internal logic.

    You run this testbench in Modelsim and create a Value Change Dump (.vcd) file. Then use Altera's power analysis tool to get a power estimate (I think that's right, its been a while since I've done it).

    Depending on the FPGA you are using, you need a machine with a huge amount of memory. For the Stratix II design I was working with, I ended up created designs with 5%, 10%, 20%, 30% of the logic I planned on using in the final design, and then extrapolated to a full FPGA.

    For a worst-case power analysis, you can create a Qsys system with blocks of registers that you can enable to toggle their outputs. You can create a block size that is say 5% of a device, and then enable one block for a 5% power load, two blocks for 10%, etc.

    Cheers,

    Dave