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Altera_Forum's avatar
Altera_Forum
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9 years ago

Error (10759): Verilog HDL error... -> is Verilog-2001 not supported?

Hi All,

I'm receiving the "Error (10759): Verilog HDL error at rly.v(18): object rl_sck declared in a list of port declarations cannot be re-declared within the module body" on the following code: 


module rly 
 (//** System
  input           clk,
  input           rstn,
  output          rl_sck,
);
//////////////////////////////////////////////////////////////////////
//* DECLARATIONS
//////////////////////////////////////////////////////////////////////
reg            rl_sck;
endmodule

why this is an error? This is actually a legal verilog-2001 syntax. This module is defined as SystemVerilog HDL file in Quartus-II.

Thank you!

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    9 years ago

    SystemVerilog is SystemVerilog-2005, and the LRM 19.8 says:

    --- Quote Start ---

    For the first port, if neither a type nor a direction is specified, then it shall be assumed to be a member of a

    port list, and any port direction or type declarations must be declared after the port list. This is compatible

    with the Verilog-1995 syntax. If the first port kind or data type is specified, but no direction is specified,

    then the port direction shall default to inout. If the first port direction is specified, but no port kind or data

    type is specified, then the port shall default to a net of net type wire. This default net type can be changed

    using the ‘default_nettype compiler directive, as in Verilog.

    --- Quote End ---

    So because you declared rl_sck as output, it defaults to wire type and cannot be re-declared

    So yes - it is legal 2001 syntax, but not 2005 (which systemverilog is)
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    9 years ago

    Thanks! It's really that SV-2005 is no so compatible with V-2001!

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    9 years ago

    --- Quote Start ---

    Thanks! It's really that SV-2005 is no so compatible with V-2001!

    --- Quote End ---

    Yes - SV is not fully backward compatible.