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Altera_Forum
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13 years ago

how to constrain my output port

hi Alt-Gurus: I am constraining my output port say 'foo' in the usual way set_output_delay –clock clk_A –max 3 [get_ports “foo”] Now this port is driven by a register which is clo...
Altera_Forum's avatar
Altera_Forum
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13 years ago

The clock used by set_output_delay should be whatever clock the external register is using -- I assumed it is clk_A.

You don't need to use get_fanouts, if it's not possible/convenient.

Just use any combination of -from/-through/-to to restrict the affected paths.

Ie, -from [get_ports foo] should be enough.

But multi-cycle paths can be tricky, specially when they involve different clocks.

Read this first:

http://pt.scribd.com/doc/14475172/multi-cycle-paths