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

MAX_FANOUT problem

Hi

I have set a global fanout constraint to 25 and the tool is also inserting cells as shown in the info generated.

But still when i see the fitter report there are NON-GLOBAL signals with fanouts of 400 .

Even by using the assignment editor if i set the instance fanout assignments for those signals the tool is accepting it and no report for ignored fanout assignments are genrated but still the signals are having the same fanout if i check the fitter rpt.

The state is quite confusing that the assignment is not ignored and not even implemented.

Please guide me with this.

Thanks

2 Replies

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

    There could be answer that the signals are outputs of a combinatorial black and the max_fanout constraint applies only to registers .

    Is there a way to constraint the fanouts of combinatorial blocks.
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    Hi,

    Synthesis report <project>.map.rpt has "Registers Duplicated to Honor Maximum Fanout Requirements" section.

    It lists all the registers, required fanout and number of duplicated registers created for those registers.

    Thanks,

    Evgeni