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Is it necessary to have set_load and set_drive in SDC file, when IO libary is used for P&R

I am designing P&R for a project using Encounter.I modified the netlist of the design, created a top dummy module which contains both the core design and IO cells. After I input the design, I got a lot of errors like the ones below.

**ERROR: (TCLCMD-917): Cannot find 'ports' that match 'clk' (File results/matrix.sdc, Line 15).

The reason I got those errors is because I have some set_drive and set_load commands in the SDC file and there is no ports for the top dummy module in the netlist. I am wondering whether set_load and set_drive are still needed in SDC file, if IO cell library is included as Encounter P&R design input. Or I need to add a port list for the dummy top module.

Thanks in advance

BobD over 15 years ago

Now that you have the IO cells in the design, the loads and drive strengths should be characterized by the .lib models for the IO cells. The timing constraints previously used to model these things can be safely removed.
Hope this helps,
Bob
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Greatrebel over 15 years ago

Thank you very much for your help, Bob
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