Constant port map in component instantiation

[Chi Fung]

I understand that the standard format for component instantiation
using port map is

U1: comp1
port map(component_pin=>signal_node);

where signal_node has been declared previously right
below the currrent architecture.

My problem is, let say, if I want to port map component_pin
to a constant, e.g. '1' instead of signal_node, how am I
suppose to code that? I have tried

port map(component_pin=>'1');

but it doesn't seem to work.

Thanks for any hints.

[mjen...@iastate.edu]

On Mon, 16 Aug 1999 09:52:36 +0800, "Chi Fung" <cff...@sp.edu.sg>
wrote:

>
> port map(component_pin=>'1');
>
>but it doesn't seem to work.
>
>Thanks for any hints.
>
>

constant assignments at the port map are a feature of VHDL '93.

MJ

[Richard Wilkinson]

Chi Fung wrote:
>
> I understand that the standard format for component instantiation
> using port map is
>
> U1: comp1
> port map(component_pin=>signal_node);
>
> where signal_node has been declared previously right
> below the currrent architecture.
>
> My problem is, let say, if I want to port map component_pin
> to a constant, e.g. '1' instead of signal_node, how am I
> suppose to code that? I have tried
>

> port map(component_pin=>'1');
>
> but it doesn't seem to work.
>
> Thanks for any hints.

Define a constant of type std_logic equalling '1':

constant ConstantValue : std_logic := '1';
U1: comp1 port map(component_pin => ConstantValue);

Cheers,

Rich

[Andy Peters]

Richard Wilkinson wrote in message <37B7C06B...@art-render.com>...

>Define a constant of type std_logic equalling '1':
>
>constant ConstantValue : std_logic := '1';
>U1: comp1 port map(component_pin => ConstantValue);

Hmmm ... I've tried that before; doesn't work. Maybe it's an FPGA
Express/VHDL'87 thing.

I create a "constant signal" instead:

signal vcc : STD_LOGIC;

begin -- architecture

vcc <= '1';

u1 : meshugga (pin1 => vcc ... );

works for me. ymmv.

--
-----------------------------------------
Andy Peters
Sr Electrical Engineer
National Optical Astronomy Observatories
950 N Cherry Ave
Tucson, AZ 85719
apeters (at) noao.edu

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