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Verilog generics on vhdl instances

fbochud

 Hi,

I'm trying to use verilog generic on my vhdl instance via the defparam option of ncelab and I get the following message:

"Attempted propagation of defparam results to a non-Verilog instance"

The generic in my dut instance are not set and use the default value. Is that not supported?

 

Example: 

module tb_top;

   parameter G_DATA_WIDTH = 8;

   wire [G_DATA_WIDTH-1:0] data_in;

   wire [G_DATA_WIDTH-1:0] data_out;

  [...]

   /* DUT */
   top #(.G_DATA_WIDTH (G_DATA_WIDTH))
   my_dut (
        .clk                 (clk),
        .data_in         (data_in),
        .data_out       (data_out),
     );

endmodule

 Thank you for the help

Florian

Parents

  • NC as a tool does not allow you to propagate the new value across the language boundary. The default initial value of the parameter is taken as its value.

    The defparam statement tries to re-propagate the value of G_DATA_WIDTH in the VHDL instance and this warning suggests that the tool is not able to do so and retains the value of G_DATA_WIDTH to be 8 only.

    A VHDL generic is an elaboration time constant and we do not have a way to re-evaluate it based on a new defparam statement.

    To work around this, you can use the "-gpg" flag or a combination of “-defparam/-generic” options .

    % irun -mess ...... -generic "tb_top.my_dut.G_DATA_WIDTH => 16"

    Or

    % irun -mess ...... -gpg "tb_top.my_dut:G_DATA_WIDTH => 16"

Reply

  • NC as a tool does not allow you to propagate the new value across the language boundary. The default initial value of the parameter is taken as its value.

    The defparam statement tries to re-propagate the value of G_DATA_WIDTH in the VHDL instance and this warning suggests that the tool is not able to do so and retains the value of G_DATA_WIDTH to be 8 only.

    A VHDL generic is an elaboration time constant and we do not have a way to re-evaluate it based on a new defparam statement.

    To work around this, you can use the "-gpg" flag or a combination of “-defparam/-generic” options .

    % irun -mess ...... -generic "tb_top.my_dut.G_DATA_WIDTH => 16"

    Or

    % irun -mess ...... -gpg "tb_top.my_dut:G_DATA_WIDTH => 16"

Children

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