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-   -   how to test benching a bidircetional port? (http://www.fpgacentral.com/group/showthread.php?t=66112)

jtj 10-02-2003 03:56 PM

how to test benching a bidircetional port?
 
Hi All

I would like to test a bi-directional port in a test bench.
To generate the test bench I use Bencher, a GUI tool that is bundled with
Xilinx ISE.
Assigning OUTDATA to PADPIN works fine but when I try to assign a value to
PADPIN form the test bench
Modelsim gives the following error: "Nonresolved signal padpin has multiple
sources."

What is the trick? -Any help is appreciated since I'm starting to be
frustrated.

Thanks in advance
-Jan


-------------------------------------------------

library IEEE;
use IEEE.std_logic_1164.all;

entity BIPAD is port (
PADPIN : inout std_ulogic_vector(15 downto 0);
RD : in std_ulogic;
WR : in std_ulogic;
OUTDATA : in std_ulogic_vector(15 downto 0);
INDATA : out std_ulogic_vector(15 downto 0));
end BIPAD;

architecture test of BIPAD is

begin
PADPIN <= OUTDATA when (WR = '1' and RD = '0') else "ZZZZZZZZZZZZZZZZ";
-- PADPIN <= OUTDATA when (WR = '1' and RD = '0'); --else
"ZZZZZZZZZZZZZZZZZZZZZZZZ";
INDATA <= PADPIN when (WR = '0' and RD = '1');
end test;





Allan Herriman 10-03-2003 05:14 AM

Re: how to test benching a bidircetional port?
 
On Thu, 2 Oct 2003 15:56:10 +0200, "jtj"
<[email protected]> wrote:

>Hi All
>
>I would like to test a bi-directional port in a test bench.
>To generate the test bench I use Bencher, a GUI tool that is bundled with
>Xilinx ISE.
>Assigning OUTDATA to PADPIN works fine but when I try to assign a value to
>PADPIN form the test bench
>Modelsim gives the following error: "Nonresolved signal padpin has multiple
>sources."
>
>What is the trick? -Any help is appreciated since I'm starting to be
>frustrated.


Change that signal from std_ulogic(_vector) to std_logic(_vector).
This will make it a resolved signal, which matches what you are trying
to do.
BTW, The 'u' in std_ulogic stands for 'unresolved'.

Allan.


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