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Altera_Forum's avatar
Altera_Forum
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13 years ago

fast io assignment ignored

I used a fast io assignment for my input and output flops and it got ignored in the fitter (listed as such in the fitter report) I am guesing this is because of using a global clock to clock the...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
13 years ago

All fast I/O can be driven by a global, and in most designs, are driven. The most common reason I've seen is that there's logic between the register and the I/O cell. (Check Technology Map Viewer, not just your RTL, to see if something got synthesized differently than expected).