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Power port connection

Greatrebel

Hi all,

 I have some problem with power/ground port connection. The problem is that when I did special routing, the power and ground were not connected. I got some clue from Encounter log to check my netlist. So I instantiated power and ground cells under the top module which is a dummy module and includes all IO cells and the core design module.

I added two pins in the pin list of the top module as well, called VDD_PIN and VSS_PIN. In my design, the global power/ground net are called VDD/VSS. The power pad cell has two inout ports, I connected one of them to the VDD_PIN. For the other one, according to the specification, it should be connected to core. But I do not know where I should connect it to. If I connect it to the power net VDD, I will get a warning saying "This can create a short circuit if the output is 0.  Check the connectivity in the netlist." So I just leave it floating.

 When I tried to connect power/ground port to global net VDD/VSS by using 

GlobalNetConnection: VDD -pin VDD_PIN -inst * -type pgpin -module {}
GlobalNetConnection: VSS -pin VSS_PIN -inst * -type pgpin -module {}

I got errors below:

A global net connection rule for connecting P/G pins of the pattern 'VDD_PIN' was specified.  But the connections cannot be made because there is no such pin in any cell.  Check the pin name pattern and make sure it is correct.

A global net connection rule for connecting P/G pins of the pattern 'VSS_PIN' was specified.  But the connections cannot be made because there is no such pin in any cell.  Check the pin name pattern and make sure it is correct.

Any help for how to connect power/ground ports will be greatly appreciated.

 

Thanks in advanced

Wei

Parents

  •  On the sroute form, there are many options of things to connect. It looks like you may be selecting the options to connect blocks and IO cells without meaning to. (Blocks would be non-std cell macros, like RAMs, analog blocks, or other IP.) If you don't have any blocks but told sroute to route to them, then you would see this warning. You can probably ignore it, but I understand you wanting a clean run with no warning messages.

    As for the IOs, it looks like you may be trying to create a pad ring - I'd have to check the sroute options for that. But take a closer look at the form (I'm assuming you're using the gui and not command-line), and make sure you only have the things checked that you really want to connect.

    For your IO voltage, if you have components in your design that will connect to a 2.5v source, then you probably need a global connect statement for those. If it's only the IO power that is 2.5v, then that is usually taken care of by the IO cells abutting each other, and you don't have to do anything. It's hard to say without knowledge of your design though.

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  •  On the sroute form, there are many options of things to connect. It looks like you may be selecting the options to connect blocks and IO cells without meaning to. (Blocks would be non-std cell macros, like RAMs, analog blocks, or other IP.) If you don't have any blocks but told sroute to route to them, then you would see this warning. You can probably ignore it, but I understand you wanting a clean run with no warning messages.

    As for the IOs, it looks like you may be trying to create a pad ring - I'd have to check the sroute options for that. But take a closer look at the form (I'm assuming you're using the gui and not command-line), and make sure you only have the things checked that you really want to connect.

    For your IO voltage, if you have components in your design that will connect to a 2.5v source, then you probably need a global connect statement for those. If it's only the IO power that is 2.5v, then that is usually taken care of by the IO cells abutting each other, and you don't have to do anything. It's hard to say without knowledge of your design though.

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