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Altera_Forum's avatar
Altera_Forum
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17 years ago

ECO and global signal constraints

Hi

I'm often running into the following problem:

I try to make some simple ECOs in a design. When committing them, I get warnings about global signals that cannot be implemented ("Warning: Can't implement Global Signal option for node <somedefinedanduserpromotedclock> that drives nodes that cannot change routing due to incremental compilation -- other nodes are affected") and finally a fitter error ("Error: Following nodes use the same resource <someclock>").

The warning shows up for all clocks that I promote to a global signal. The design fits when compiling normally (didn't try different netlist configurations).

The change does not concern any of these clocks. In one case I remember, I routed an additional signal to a pin (kind of manual signal probe). In an other one I inserted an LCELL by hand.

Am I doing something wrong here? Or is that something I have to live with?

Thanks and regards,

emanuel

2 Replies

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

    The following is the cause of the error message (from Quartus II Message Help):

    "There are too many nodes that use the specified resource. Perhaps they are placed too close to each other. For example, they may all be placed on the same side, or the design may have assigned the nodes to use the same type of resources when other types are available."

    Do your ECO changes contribute to the above condition? For example, is the new LCELL placed too close to the nodes in the error message?

    - Ivan
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    17 years ago

    Well, I didn't get the reason for this message the first time, but now that you ask it this way... I have to check this, even if I don't think this is the problem.

    Thanks

    emanuel