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how to fix channel gap

gops
Can any one please tell me how to fix the (channel gap) spacing between the adjacent macros?

  •  Can you be more specific or post a picture of the problem?

  • You can maintain a fixed distance between two blocks using relative floorplan constraints. See the following solution for examples and details:

    http://support.cadence.com/wps/mypoc/cos?uri=deeplinkmin:ViewSolution;solutionNumber=11649020

    Hope this helps,

    Brian

     

  • Thank Kari and Brian for your replies. I think my query is not so clear. Please find the attached picture. In the picture there are measurements shown with red arrows .

    I would like to know how to fix these gaps

    a) spacing between both macros ( 50um in the diagram)

    b) spacing between macro and standard cells .

    thanks
    Gops

  • Hi Gops,

    For spacing between the macros and std cells, use a halo on the macro. (Looks like you have one, but it's very small.) Go to Floorplan->Edit Floorplan->Edit Halo. Select the macro you want and then pick "Selected Blocks/Pads" on the form. Type in the distances you want for top/bottom/left/right and hit OK.

    For the space between macros, I think the relative floorplan functions that Brian suggested are your best shot.

     - Kari

  • Hi Kari,
     
    I have fixed the space as 50um between the macros. But I choose the space as 50um as random. I need to know whether there is any rules by calculating the channel gap. Can you please tell me how I can do the same.
     
    thanks
    Gops

  •  There's no single rule. It's going to depend on your design. Do you need to get routing inbetween the macros? Do you need to place std cells between the macros? If so, you need to make sure there is enough room to get your power grid in between too. Are these macros analog blocks that may require some extra clearance? The minimum is that you pass DRC rules. But other design considerations like I mentioned may mean that you need more than the minimum room.

  • is there any rule of thumb like Total number of nets crossing / total number of pins facing the channel * MET2 pitch

  •  I don't have any rule like that, but try the estimatePtnChannel command. Even though it sounds like it only works on partitions, I think it works on macros too.

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