Adding header files in Verilog

Question

I wanted to add a header file to my Verilog project. This should be a very easy thing to do. However, it turns out is is not trivial. This my header file. Let's say the file name is parameters.vh

`ifndef _parameters_vh_
`define _parameters_vh_
parameter Tm = 2;
parameter Tn = 2;
`endif

Then I include it to the top module

`include "parameters.vh"

But it cannot get synthesized. This is the error message:

Verilog HDL error at parameters.vh(3): declaring global objects is a SystemVerilog feature. I am wondering if anyone can help me here.

Martin Zabel · Accepted Answer · 2015-12-12 13:43:18Z

3

In Quartus-II, you can enable SystemVerilog features via menu Assignments -> Settings -> Verilog HDL Input.

Otherwise you have to move the inclusion of the parameters file within a module definition like here:

module top (x,y);
`include "parameters.vh"
   input x;
   output y;
   assign y = x;
endmodule // top

answered Dec 12, 2015 at 13:43

Martin Zabel

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1 Comment

dave_59 Over a year ago

Although it is legal in SystemVerilog, it is never a good idea to put global definitions outside a module. Much better to put them in a package and import the package.

Sam · Accepted Answer · 2015-12-15 20:56:27Z

1

it's not a systemverilog issue, just think of what the pre processor is doing when it finds your include line. you can't have parameters outside modules, doesn't make sense.

answered Dec 15, 2015 at 20:56

Sam

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