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17268 Discussions

how to determine the parameter of set_max_fanout?

Altera_Forum
Honored Contributor II
2,566 Views

Hi: 

I have known the function of set_max_fanout,but I don't understand how to confirm the parameter which following set_max_fanout.please help me! 

thank you!
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4 Replies
Altera_Forum
Honored Contributor II
1,591 Views

That's the max fanout value. So if a register has a fanout of 35, and you do that assignment, you'll end up with 5 copies, 4 that have a fanout of 8 and 1 that has a fanout of 3. The following might help: 

http://www.alterawiki.com/wiki/register_duplication_for_timing_closure
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Altera_Forum
Honored Contributor II
1,591 Views

is the parameter confirmed acconding to the target library?

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Altera_Forum
Honored Contributor II
1,591 Views

Are you talking about an ASIC? 

Max fanout is your constraint that you would manually enter to help timing. You can enter whatever value you want. The main purpose is to help the fitter place logic closer together, and hence achieve better timing.
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Altera_Forum
Honored Contributor II
1,591 Views

ok,I will look up some data.thanks for your response!

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