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Constraint File Variable Definitions

rrsquez

Hello. The following is a line from the MicroZed constraint file (microzed_7z010_master_XDC_RevB_v1.xdc).

Here is one line:

set_property PACKAGE_PIN T10 [get_ports{JX1_LVDS_0_N}]

Where is definition for "JX1_LVDS_0_N" and the other variables used in these constraint files?

 

Another example:

The Zedboard also has a constraint file (zedboard_master_XDC_RevC_D_v3.xdc) that also uses variables in this manner.

Here is one line: 

set_property PACKAGE_PIN U11  [get_ports {OLED_VBAT}];  # "OLED-VBAT"

Again, where would the "OLED_VBAT" variable be defined? It is a number between 54 and 57.
 

Thank you, Richard V

  • 0

    When pinning differential pairs in a constraint file, you only need to enter in the _P.  The _N will automatically come along for the ride!

    If you use those pins for SINGLE ended, you will need to modify the constraint.

    --Dan

  • 0 in reply to drozwood90

    Hello Dan. Sorry, but you still haven't answered my question.

    This is 1 line from the constraint file provided on the website:

    set_property PACKAGE_PIN T10 [get_ports{JX1_LVDS_0_N}

     

    Again, I have to ask:
    Where is definition for "JX1_LVDS_0_N" and the other constants used in these constraint files? I didn't create this file. I don't care that it's a differential signal.

     

    Thank you, Richard V

  • 0

    Richard,

    I think I am not understanding what you are asking.  Let me try again and let me know if I am not answering you.

    The name JX1_LVDS_0_N comes from the definitions in the tool, which can be objects in the code or just created in the XDC.

    Vivado KNOWS what T10 is.  It is given that association based on the package you choose.  From there, get_ports is a XDC call that gets all objects that are ports.  Lastly, the JX1_LVDS_0_N is a name Avnet created that is the same name (or similar) given by our schematic.  If your design is not using that signal, you can remove it from the constraint as it will only cause you warning messages.

    --Dan