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Altera_Forum's avatar
Altera_Forum
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14 years ago

Fitter ignores fast i/o assignments.

Why does fitter ignore the sdram fast i/o assignment? The warning is: 

Warning (176250): Ignoring invalid fast I/O register assignments. See the Ignored Assignments panel in the Fitter Compilation Report for more information.

Ignored registers are "za_data[*]~reg0" and "m_data[*]". Why?

1 Reply

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

    Quartus can't promote registers to IO registers when:

    for outputs: you read the output signal back in your logic

    for inputs: you use both registered and unregistered inputs in your logic