IsPortConnected < P1076

P1076 Web>Vhdl2019CollectedRequirements>IsPortConnected (2020-07-02, JimLewis) (raw view)EditAttach

---+ API and Attributes for PSL



---++ Proposal Editing Information
   * Who Updates: 
   * Date Proposed: 2020-June-4
   * Date Last Updated: 
   * Priority:
   * Complexity:
   * Focus: Testbench
   * Proposal Maturity: 
---++ Requirement Summary

In VHDL, it is allowed to leave an output port of a component open. Is there a function to detect that from within the component so that other hardware could be generated?

I don't want to wait on the optimisation step, since I would like to modify the hardware in case a port is left open.

Specifically, I'm generating a component with differential output, in which I would like to include a OBUFDS in case both _P and _N are connected, and I don't want to include that component in case the _N is left open.


---++ Rationale



---++ Related and/or Competing Issues:



---++ Proposal

---+++ Attribute Determined at Elaboration Time

<verbatim>
CreateDriver : if Sig_N'Driven generate -- Attribute name up for discussion, Driven, Undriven, 

  ... -- instantiate a differential driver

else

  ... -- instantiate a single driver to drive Sig_P only

end generate CreateDriver ;
</verbatim>

Also need to be able to do Sig.N'Driven where sig is:
<verbatim>
type SigType is record
  N : std_logic ;
  P : std_logic ; 
end record SigType ; 
</verbatim>

---++ Questions

---++ General Comments


---++ Supporters


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Topic revision: r2 - 2020-07-02 - 19:11:12 - JimLewis

P1076