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Fitter ignores fast i/o assignments.

Altera_Forum
Honored Contributor II
‎04-07-2012 03:27 PM
1,778 Views

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?
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Altera_Forum
Honored Contributor II
‎04-11-2012 11:56 AM
650 Views

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
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