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Altera_Forum's avatar
Altera_Forum
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13 years ago

Generic component inside generic component

Hello.I am designing a vhdl code that has a generic size setting a bunch of operations.I cannot synthetize it with quartus (Error (10346): VHDL error at mac.vhd(7): formal port or parameter "width" must have actual or default value), but I am able to compile with modelsim.My question is, can I put a generic component inside another? If dont, how should I proceed?

entity mac is

generic (

width : integer); -- QUARTUS POINTS HERE

port (

clk : instd_logic;

rst : instd_logic;

a_i : instd_logic_vector(width-1downto0);

b_i : instd_logic_vector(width-1downto0);

acc : instd_logic_vector(2*width-1downto0);

out_o : outstd_logic_vector(2*width-1downto0)

);

end mac;

architecture bhv of mac is

component mul

generic (

W_g : integer);

port (

clk : instd_logic;

rst : instd_logic;

a_i : instd_logic_vector(W_g-1downto0);

b_i : instd_logic_vector(W_g-1downto0);

outm_o : outstd_logic_vector(2*W_g-1downto0)

);

endcomponent;

component soma

generic (

W_gs : integer);

port (

clk : instd_logic;

rst : instd_logic;

outm_o : instd_logic_vector(2*W_gs-1downto0);

acc : instd_logic_vector(2*W_gs-1downto0);

outs_o : outstd_logic_vector(2*W_gs-1downto0)

);

endcomponent;

5 Replies

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

    You can put generics anywhere you like. The error is due to the fact you did not assign a value anywhere. Modelsim would have produced the same error had you tried to elaborate the design.

    You can set generics using Quartus and Modelsim commands, however, you can also set a default value in your design, eg, 

    
generic (
    width : integer := 8
);

    The width generic can then be overridden in Modelsim using vsim option -gwidth=16, and in Quartus via the set_parameter Tcl command (or using the GUI).

    Cheers,

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

    Value of width is provided by another entity.

    I found what was wrong. I didnt knew i have to set the top level entity.

    But thanks =D
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    --- Quote Start ---

    Value of width is provided by another entity.

    --- Quote End ---

    Right, but the error was because the component MAC did not have a value set.

    --- Quote Start ---

    I didn't knew i have to set the top level entity.

    --- Quote End ---

    Ah, I see, you accidentally had MAC as the top-level component.

    I have got into the habit of putting default values in the entity/architecture file so that I can run a synthesis check, and then deleting them on the component definition in a package, so that I don't forget to put the generics on the component when I instantiate it.

    Cheers,

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

    No, the error was because the component MAC get its value from another entity, a top-level one.

    Thanks for the hint
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    --- Quote Start ---

    No, the error was because the component MAC get its value from another entity, a top-level one.

    --- Quote End ---

    Ok, you didn't put the generic map on the component when you instantiated it.

    It sounds like you've got things sorted out now.

    Note that if you have a generic (or a port) that would normally take on a specific value, then in your component definition, you can supply a value, and then that value will be used if you do not list that generic (or port) in the generic map.

    Cheers,

    Dave