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[500milesaway]

Hello everyone,
I am very new in VHDL programming. For my work I am using ISE 10.1 and ModelSim XE III 6.3c. I am facing some problems in programming a simple code. the code is as follows:
------------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity test is
port(
clk: in std_logic;
in_i1: in std_logic_vector(7 downto 0);
out_i1: out std_logic_vector(7 downto 0)
);
end test;

architecture a of test is
signal signed_out_i1: signed(7 downto 0);

begin

process(clk)
begin
if (clk'event and clk = '1') then
signed_out_i1 <= -signed(in_i1);
end if;
end process;

out_i1 <= std_logic_vector(signed_out_i1);

end a;
----------------------------------------

Problem # 1:

I want "signed_out_i1" will be changed to negative of "in_i1" at each clock change to 1. the behavioral (functional) simulation works alright and shows the expected result. But the in the Post-translate simulation the output is not as expected. I used the following testbench code:

--------------------------------------
library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity test_tb is
end test_tb;

architecture test_tb_arch of test_tb is
component test
port(
clk: in std_logic;
in_i1: in std_logic_vector(7 downto 0);
out_i1: out std_logic_vector(7 downto 0)
);
end component;

signal clk: std_logic;
signal in_i1,out_i1: std_logic_vector(7 downto 0);

begin
aaaa: test port map(clk,in_i1,out_i1);

process
begin
clk<='0';
in_i1<="11111111";
wait for 50 ns;

clk<='1';
in_i1<="00000001";
wait for 50 ns;

clk<='0';
in_i1<="00000001";
wait for 50 ns;

clk<='1';
in_i1<="11111111";
wait for 50 ns;
end process;

end test_tb_arch;

configuration AOA of test_tb is
for test_tb_arch
end for;
end AOA;
-----------------------------------------------------------
the expected output should be either "00000001" or "11111111". But in the output it shows "11001001" and "00110111". Can anyone explain what is the problem?

Problem # 2:
Another problem is that when I run Post-map Simulation or Post-route simulation in ISE 10.1 the simulation output is not shown in Modelsim. It shows the following ERROR in ModelSim:

# ** Warning: Design size of 12274 statements or 0 non-Xilinx leaf instances exceeds ModelSim XE-Starter recommended capacity.
# Expect performance to be quite adversely affected.
# ** Error: (vsim-SDF-3250) netgen/map/test_map.sdf(0): Failed to find INSTANCE '/UUT'.
# Error loading design
# Error: Error loading design
# Pausing macro execution
# MACRO ./test_tb.mdo PAUSED at line 8

How to solve the problem?

I will be very greatful if anyone can help me to solve the problems.

Thanks and best regards,

Pantho

[muddassir_asif]

Hi!
i am having same problem, i am using ISE 8.1 adn modelsim 5.7f.
when i run post-map and post route simulation, modelsim gives error...

** Error: (vsim-SDF-3250) C:/Xilinx/xorrngxilinx3/netgen/map/xorrng1_map.sdf(0): Failed to find INSTANCE '/UUT'.
# Error loading design

can anyone please help me!! i really need to do post-par simulation!
thanks in advance

[joris]

That means, you need to rename the component you are testing, to UUT. You currently have "aaaa" as name. Xilinx assumes the name to be "UUT"

In case you don't want to do that, you can:

1. Right-click "Simulate Post-Place and Route model"
2. Change the value of "ISim UUT Instance Name" (clicking the value field, it becomes editable)

Hope that helps,

Joris

[Mike]

I the warning below when I tried to perform post PAR simulation.

Loading work.tb_post_par_sim(func)
# ** Warning: (vsim-3473) Component instance "uut : ssdn_bb_fpga_ert_timesim" is not bound.
# Time: 0 ps Iteration: 0 Region: /tb_post_par_sim File: tb_post_par_sim.vhd

Please help on resolve this. I already spent more than a week to deal with this problem.

Thank you very much.

Mike