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A problem with a BlackBox

meri

 Hi! I'm using a RAM of the AMS in my digital circuit. 

I've defined a blockbox with the line:  setImportMode -treatUndefinedCellAsBbox 1, and now I'm trying to load its floorPan (because I would like to see in the layout the metal of this block). These are the errors and warnings (they appears either if I load the floorPlan before then after defining the floorplan of the whole circuit):

**ERROR: Die Area is not defined
**WARN: Design Area's lower left corner is not on manufacture grid.
**WARN: Design Area's upper right corner is not on manufacture grid.
**ERROR: Incorrect width (0.00000)

Thanks a lot! 

 

Parents

  •  Hi Meri,

    Encounter is using the LEF, whereas Virtuoso uses the actual layout. LEF is an abstract of the layout, meaning it's not the full layout - just a representation of the important parts. It will have the pins, so you can route to them, but usually blockages where other metal is.

    If you have a LEF for the RAM, then it's not really a blackbox. I'm not sure what you mean when you say the ram is "recongized as a blackbox". Maybe your LEF is incomplete. If Encounter is routing over it, then it sounds like you are missing the blockage info (the OBS section of the RAM LEF). In most RAMS, you can route over them in the top couple of layers in your process, but you should not be able to route over them in all layers. Turn on Cell Blockage in your Encounter window and then turn the metal layers on and off, one by one, to see what blockages exist.

    As for the pwr/gnd pins, you need to use Sroute to connect the RAM pwr/gnd pins to your grid. (Route->Special Route) The "Block Pins" option is what you want; see the settings for Block Pins on the Advanced Tab and select All Pins.

    I'm not sure what's going on with the filler cell and the short - could you send a picture of that?

    - Kari

Reply

  •  Hi Meri,

    Encounter is using the LEF, whereas Virtuoso uses the actual layout. LEF is an abstract of the layout, meaning it's not the full layout - just a representation of the important parts. It will have the pins, so you can route to them, but usually blockages where other metal is.

    If you have a LEF for the RAM, then it's not really a blackbox. I'm not sure what you mean when you say the ram is "recongized as a blackbox". Maybe your LEF is incomplete. If Encounter is routing over it, then it sounds like you are missing the blockage info (the OBS section of the RAM LEF). In most RAMS, you can route over them in the top couple of layers in your process, but you should not be able to route over them in all layers. Turn on Cell Blockage in your Encounter window and then turn the metal layers on and off, one by one, to see what blockages exist.

    As for the pwr/gnd pins, you need to use Sroute to connect the RAM pwr/gnd pins to your grid. (Route->Special Route) The "Block Pins" option is what you want; see the settings for Block Pins on the Advanced Tab and select All Pins.

    I'm not sure what's going on with the filler cell and the short - could you send a picture of that?

    - Kari

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