Forum Discussion

OldMarty's avatar
OldMarty
Icon for New Contributor rankNew Contributor
9 months ago

Can Instantiation components be repeated easier??

Hi all,

When Instantiating multiple components, my U1,U2,U3 "adders" would be as follows:
 
    U1 : Adder
        Port map ( A => A,
                   B => B,
                   Sum => Sum);

    U2 : Adder
        Port map ( A => A,
                   B => B,
                   Sum => Sum);

    U3 : Adder
        Port map ( A => A,
                   B => B,
                   Sum => Sum);

Is there a way (when using IDENTICAL components) to state something like the following code?:

    U1,U2,U3 : Adder
        Port map ( A => A,
                   B => B,
                   Sum => Sum);


general

3 Replies

  • FvM's avatar
    FvM
    Icon for Super Contributor rankSuper Contributor
    9 months ago

    Hi,

    no it's neither legal nor meaningful VHDL syntax.

    You can refer to formal definition of instantiation statement in VHDL language reference IEEE Std 1076

     component_instantiation_statement ::=
   instantiation_label :
     instantiated_unit
        [ generic_map_aspect ]
        [ port_map_aspect ] ;

 instantiated_unit ::=
     [ component ] component_name
     | entity entity_name [ ( architecture_identifier ) ]
     | configuration configuration_name

    U1, U2, U3 are instantiation labels, there can't be multiple lables in an instantiation.

    Semantic-wise, it makes no sense to have multiple statements with identical port mapping. In this case, you are creating multiple drivers for signal Sum. Meaningful multiple instantiations will have at least some ports different.

    Generate statements can however compact your code

    genadders: 
for i in 1 to 3 generate 
  U : Adder 
    Port map ( 
      A => A(i), 
      B => B(i), 
      Sum => Sum(i)); 
end generate;