(newbie) Configure in vhdl (freehdl)

[Javier M Mora (jamarier)]

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Hi, i'm absolute newbie and i'm trying freehdl as simulator of VHDL (it was
easiest to install in my gentoo box).

Below is halfadder.vhdl there are a line with 3 cases. In every try i
only uncomment one of them:

In 1st case: I get: "Sorry, only default component binding is currently
supported. No default binding for component halfadder found!" (it's
normal, no configure binding).

In 2nd case: I get: "halfadder is not a entity" Why? halfadder it's an
entity. It's a little above

In 3rd case: I reference halfadder inside its package: "work". but in
this time freehdl-v2cc fails an assertion (break with error message) :-(

I can run than file if I use 1st case and use
- --relaxed-component-visibility option in gvhdl. But i think that is
"cheat".

How can I set binding between architecture and components?

If the problem is freehdl is too unstable, my second choice is use
Alliance but it appears difficult to use.

What do you think about?

Thanks, javier m mora

- ----------8<---------- halfadder.vhdl
entity halfadder is
port (x,y: in bit;
s,c: out bit);
end entity halfadder;

architecture RTL of halfadder is
begin
s <= x xor y after 10ns;
c <= x and y after 20ns;
end architecture RTL;

entity test_halfadder is
end entity test_halfadder;

architecture test_halfadder of test_halfadder is
signal a,b: bit;
signal s,c: bit;
component halfadder
port (x,y:in bit; s,cut bit);
end component;
- -- --1st case
- -- for all: halfadder use entity halfadder(RTL); --2nd case
- -- for all: halfadder use entity work.halfadder(RTL); --3rd case
begin
U1: halfadder port map (a,b,s,c);
a <= '1' after 50ns, '0' after 100ns;
b <= '1' after 0ns, '0' after 75ns;
end architecture test_halfadder;
- ----------8<---------- end halfadder.vhdl
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[Paul Uiterlinden]

Javier M Mora (jamarier) wrote:

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Hash: SHA1

Hi, i'm absolute newbie and i'm trying freehdl as simulator of VHDL
(it was easiest to install in my gentoo box).

Below is halfadder.vhdl there are a line with 3 cases. In every try
i only uncomment one of them:

In 1st case: I get: "Sorry, only default component binding is
currently supported. No default binding for component halfadder
found!" (it's normal, no configure binding).

In 2nd case: I get: "halfadder is not a entity" Why? halfadder it's
an entity. It's a little above

In 3rd case: I reference halfadder inside its package: "work". but

"work" is not a package, it is a library.

in this time freehdl-v2cc fails an assertion (break with error
message) :-(

I can run than file if I use 1st case and use
- --relaxed-component-visibility option in gvhdl. But i think that
is "cheat".

How can I set binding between architecture and components?

My preferred way is to use a configuration declaration. This is a
separate design unit (design units are: entity, architecture,
package, package body and configuration).

What you use in you example is a configuration specification. It is
not a separate design unit, so there can only be one configuration
specification. Using configuration declarations, there can be more
than one, e.g. for using different implementations of a design.

The configuration declaration for your testbench would be (untested):

CONFIGURATION test_halfadder_cfg OF test_halfadder IS
FOR test_halfadder_arch
FOR ALL: test_halfadder
USE ENTITY work.halfadder(rtl);
END FOR;
END FOR;
END CONFIGURATION test_halfadder_cfg;

It is test_halfadder_cfg that you need to load into you simulator.

By the way: you should rename the architecture of test_halfadder (to
something like test_halfadder_arch, behav or simply arch). I would
not expect it to be legal to name an entity and architecture the
same. And even if it was, I would not recommend it.

If the problem is freehdl is too unstable, my second choice is use
Alliance but it appears difficult to use.

I do not have any experience with either of them. So I don't know if
my solution will work. It is legal VHDL, but I do not know whether
freehdl supports configuration declarations.

--
Paul.
www.aimcom.nl
email address: switch x and s