How to extract signal to start or stop dumping

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roger

Joined: 27 Aug 2003
Posts: 182
Helped: 7

16 Jul 2004 7:49 fsdbdumpon

How to extract signals to start or stop dumping using VHDL, ModelSim?

Please.

xigu

Joined: 05 Jul 2004
Posts: 10

18 Jul 2004 2:18 fsdbdumpoff

from modesim user manual
-->
A VCD file from source to output
The following example shows the VHDL source, a set of simulator commands, and the resulting VCD output.
VHDL source code

The design is a simple shifter device represented by the following VHDL source code:

library IEEE;
use IEEE.STD_LOGIC_1164.all;

entity SHIFTER_MOD is
port (CLK, RESET, data_in : IN STD_LOGIC;
Q : INOUT STD_LOGIC_VECTOR(8 downto 0));
END SHIFTER_MOD ;

architecture RTL of SHIFTER_MOD is
begin
process (CLK,RESET)
begin
if (RESET = '1') then
Q <= (others => '0') ;
elsif (CLK'event and CLK = '1') then
Q <= Q(Q'left - 1 downto 0) & data_in ;
end if ;
end process ;
end ;

VCD simulator commands
At simulator time zero, the designer executes the following commands:

vcd file output.vcd
vcd add -r *
force reset 1 0
force data_in 0 0
force clk 0 0
run 100
force clk 1 0, 0 50 -repeat 100
run 100
vcd off
force reset 0 0
force data_in 1 0
run 100
vcd on
run 850
force reset 1 0
run 50
vcd checkpoint
quit -sim

roger

Joined: 27 Aug 2003
Posts: 182
Helped: 7

18 Jul 2004 15:08 vcd checkpoint

What I mean is I wanna to start dumping when some signals
are active. I think you can not use run 20 ??sec, vcd file ...
because we don't know exactly the time when signals are active.
Hopt to share your idea.tks!

galant

Joined: 19 Jun 2003
Posts: 58

19 Jul 2004 4:45 fsdbdumpoff

Use the following tcl commands.
"probe -shm -all"
It can dump the all signals in verilog-xl. You can have a try in Model-sim.

roger

Joined: 27 Aug 2003
Posts: 182
Helped: 7

06 Sep 2004 10:27 fsdb extract

galant wrote:

Use the following tcl commands.
"probe -shm -all"
It can dump the all signals in verilog-xl. You can have a try in Model-sim.

In that way, the dump file would probably be too big.

AlexWan

Joined: 26 Dec 2003
Posts: 305
Helped: 6

07 Sep 2004 13:08 nwave extract signal

Have you have the PLI for debussy?

initial
begin
$fsdbDumpfile("fsdbfilename.fsdb");

wait (a_valid)
$fsdbDumpvars;

wait (b_valid)
$fsdbDumpoff;

wait (c_valid)
$fsdbDumpon;

...
...
end

Certainly, Dumping VCD have the same commands. Ref the GU of ModelSim.

Good Luck.

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07 Sep 2004 13:08 Ads

xmizi

Joined: 21 Feb 2002
Posts: 35

01 Oct 2004 20:30 dump signals in verilog

use:

initial
begin
$dumpfile("./***.vcd");
$dumpvars;
end

you can also specify the signals and level of hierarchical in the $dumpvars.

Then use debussy to translate vcd to fsdb or running power analysis or whatever you want with the vcd file

VCD is usually much bigger than fsdb etc.

roger

Joined: 27 Aug 2003
Posts: 182
Helped: 7

10 Oct 2004 8:28 tcl fsdbdumpvars

xmizi wrote:

That's verilog ,not VHDL ok!

aji_vlsi

Joined: 10 Sep 2004
Posts: 640
Helped: 72
Location: Bangalore, India

11 Oct 2004 5:50 fsdb + dumpvars

roger wrote:

Not sure if this is do-able in Modelsim. With NC you can do:

database -disable -shm;
run 100 us
database -enable -shm;

To have it controlled using a signal (as you've asked), you can use "stop" command in conjunction with this. A pseudo-code (as you don't use NC anyway).

stop -condition {/top/dump_start == 1} -execute {database -enable -shm}

stop -condition {/top/dump_stop == 1} -execute {database -disable -shm}

NOTE: Options might be wrong in the above TCL, it is an idea than actual code.

I don't find such commands in MTI, they recently intorduced some thing called wlfman - but that's for post processing.

Regards,
Ajeetha
http://www.noveldv.com

saho

Joined: 04 Apr 2003
Posts: 65

23 Nov 2004 18:49 modelsim + disable dumping

Hello.

Let me suggest a solution.

I have learned that Novas (certainly latest version Debussy and possibly Verdi) does support extraction of sub-signal waveform from a large waveform log.

The trick is it is a FSDB formatted file. Luckily, Novas has kindly provided conversion utility in its tools.

Now, if you have the orginal waveform in VCD. Novas may have a utility to convert VCD to FSDB format, Soon you have the converted FSDB file, you can load into nWave for signal extraction.

Conclusion: It is possible, albiet some pains involved. Read Novas's Knowledge base articles (you will need userID and password) and Debussy's user manual.

SAHO