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DRC rules for specific board area or chip

cosborne2000

Is there any way to create different DRC rules for specific areas or chips on a board?

 

For example, I would like to setup a large width on the ground net but this trace needs to neck down to connect to various chips.

Fine pitch devices also require a narrow trace width to connect.

 

Currently I have to approve all the errors on the fine pitch devices but is there a more efficient way?

  • cosborne2000 <communitymanager@premierfarnell.com> wrote:

    Is there any way to create different DRC rules for specific areas or chips on a board?

     

    For example, I would like to setup a large width on the ground net but

    this trace needs to neck down to connect to various chips.

    Fine pitch devices also require a narrow trace width to connect.

     

    Currently I have to approve all the errors on the fine pitch devices but

    is there a more efficient way?

     

     

    Have a look at classes.

     

  • in reply to Former Member

    Maybe there's a section I'm missing.

     

    For example: I want a 12 width/12 clearance rule for the GND net but I need an exception for the neck down on fine pitch or BGA packages.

    Is there any way I can avoid all the DRC errors that occur at the chip?

    If I set for the tighter rules for the chip then this rule applies to the whole board.

  • in reply to cosborne2000

    cosborne2000 schrieb:

     

    For example: I want a 12 width/12 clearance rule for the GND net but

    I need an exception for the neck down on fine pitch or BGA packages.

    Is there any way I can avoid all the DRC errors that occur at the

    chip? If I set for the tighter rules for the chip then this rule

    applies to the whole board.

     

    "Exceptions" from the DRC settings are currently not supported/possible

    with EAGLE.

     

    In such situations, I normally use the coarser DRC settings for the

    board and then "accept" all DRC complaints in the fine pitch area since

    I know it's OK there. (To be sure, you yould run a "finepitch" DRC before.)

     

    Tilmann

     

  • in reply to Former Member

    Any idea if V6 will handle neck downs?

     

    With fine pitch high pin count chips you can have a long list of exceptions.  It wouldn't be a big deal but if I make any type of adjustment to the chip position the DRC exceptions don't follow.