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Altera_Forum's avatar
Altera_Forum
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15 years ago

Using I/O registers

Can anyone tell me how I can specify that I want to enable the registers/flipflops at the input buffers (ie. use register packing at the I/O buffers) in Quartus II?

I have spent a few minutes searching for this in Q II with no obvious answer.

I am currently using the Cyclone II.

3 Replies

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

    Thanks that's indeed what I meant, but the "Fast Input" option disappears if the I/O type is LVDS. Is it not possible to have fast inputs with LVDS?

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    You probably have DDR input on those pins too, in Cyclone DDR is done inside the logic fabric and not in the IO-ring so the Fast Input Register is not possible.