Major Tools
Other Tools
General Info

This is a list of frequently asked questions (FAQ) for Dinotrace users. A hypertext version is available on the web at /faq.html.

Please send updates and corrections to the FAQ to

1. General Questions

1.1 Where can I get the latest version of Dinotrace?

The latest version is Dinotrace 9.4e. It can be down-loaded from the veripool, at

1.2 Can I copy Dinotrace?

Dinotrace is covered under two Copyrights. The latter one is the GNU Copyleft, which allows free use and modification, provided that you in turn provide free use and modification to all others that request it. This is described in the ‘COPYING’ distributed with Dinotrace.

Code created before 1998 was Copyrighted by Digital Equipment Corporation. Their Copyright also disclaims any warranties, and disallows reproduction for sale. Observing the GNU Copyleft should also cover this Copyright for any software distributed not for a fee. (The water is murky if embedding Dinotrace.)

1.3 Where should I report bugs and other problems with Dinotrace?

Currently the author is tracking bugs; contact There is a Anti-Spam filter on this account, so be sure you have a valid return address to meet the filter’s challenge.

1.4 What other public domain tools work with Dinotrace?

The primary tool you will want are GNU Emacs, with ‘verilog-mode.el’, ‘dinotrace.el’, and ‘sim-log.el’ installed. This will let you back-annotate the values of signals onto your source code.

You may also want Verilator, a public domain simulator, and other tools available at the Veripool.

1.5 Will Dinotrace work with Windows NT/Windows XP?

Yes, though it may not have the look and feel you expect. (Because your expectations were unfortunately defined by Microsoft, not Unix.) Some consider that a feature.

Read the installation instructions on the Website. You’ll need cygwin, and a bunch of subpackages that are a part of cygwin.

2. On-line Help, Printed Manuals, Other Sources of Help

2.1 How do I get a printed copy of the Dinotrace manual?

A html file is available at /index.html. Your web browser should be able to print this.

The more ambitious can build the manual themselves. The texinfo source is included with Dinotrace. Typing ‘make dinotrace.dvi’ will create a dvi file that may then be printed with ‘dvips’. This will require TeX, texinfo, and a bunch of libraries, all good for a day’s worth of downloading.

2.2 How do I install a piece of Texinfo documentation?

An info file for Dinotrace comes with the package, ‘’. Copy this file to a directory in your info path, usually ‘/usr/local/info’. Then edit the master directory, usually ‘/usr/local/info/dir’ to include the line:

  * Dinotrace: (dinotrace).  Signal waveform viewer

3. Common Things People Want To Do

3.1 How do I have dinotrace always display a group of signals together?

Dinotrace doesn’t really have the concept of groups yet. Instead, use the signal_move or signal_copy to accomplish the desired effect.

For example, if out of a huge trace you want only ‘foo’ and ‘bar’ to be displayed, put in your ‘dinotrace.dino’:

signal_delete *
signal_add foo
signal_add bar

Dinotrace will create similar code for you by selecting the Customize Save As... menu option then checking the Save signal ordering box.

3.2 How do I make a signal that is a concatenation of other signals?

Dinotrace will only collapse signals with the same basename. Make another signal that is a concatenation of the two.

If the signal is never used, then it will be eliminated by Synopsys. If you’re using Verilint or a similar tool that finds unused nets, you may want to make another signal, unused_ok, to make it obvious that the net is fake. The below example does this. It uses the weird ORing on unused_ok so that any number of any width signals can be added in, yet it will still always hold a constant high.

wire [2:0] first;
wire [7:3] second;
wire [7:0] concatenated_for_dino = {first, second};
wire unused_ok = (|{

3.3 How do I find the next time a signal changes?

There is no direct way to move to the next edge. You can see the next time that the value changes by using Value Examine or <MB2>, then pan to that point manually or with Goto.

3.4 How do I make a "register window" with the values at a current time?

Just make a fake Verilog file with the registers laid out in ASCII as you wish. Then use the Emacs Dinotrace keys to annotate and manipulate the values. You can even have the signals commented out in your normal module; annotation updates comments too. (As long as the needed signals are uncommented elsewhere in the module.)

4. Bugs/Problems

4.1 How do I get around the "Over maximum of 256 signal states" error message?

You have two basic options. First, for one hot and similar state machines, define another less wide signal that is derived from the wide signal, then apply a signal_state command to that new signal.

Alternatively, do the decoding in Verilog. A Configuration Command signal_radix *_ascii* ascii with the code below should work:

reg [8*4-1:0] machine_ascii;	// Decoded ascii state of machine
always @ (/*AUTOSENSE*/machine) begin
   casex ({machine})
    4'b0000: machine_ascii = "----";
    4'b1000: machine_ascii = "s0  ";
    4'b0100: machine_ascii = "exit";
    4'b0010: machine_ascii = "stop";
    4'b0001: machine_ascii = "idle";
    default: machine_ascii = "%ERR";

4.2 Why do I see X’s for a bus that isn’t all X’s?

If a signal value has even a single bit that is X or Z, but isn’t entirely X or Z, then it will be displayed as X. You can see the real value by using Value Examine or <MB2>.

4.3 Why does(n’t) Dinotrace compress bits into a single vector?

Dinotrace must form all vectors when the trace is being read in. The vector_separator command must be set to the character used to separate bus bits from the rest of the signal name. If you don’t want bits to be collapsed to vectors, just set it to some character that doesn’t occur in signal names, like @.

4.4 Why doesn’t a signal appear in Dinotrace?

Check first that it is really in the trace. The strings program will find signal names in every format that Dinotrace supports.

If the signal exists in the trace, it may have been deleted by a configuration command. Use the Signal Select popup to add all signals, then use Signal Search to find it.

In Verilog VCD files, if a identical signal exists at many levels of hierarchy, only the top level signal will exist. If your naming convention is sane, and doesn’t change names at hierarchy boundaries, you still should find the signal, just with a different hierarchy in front of the base signal name. Furthermore, signals with over 1024 bits are dropped, since they would take too much space on the screen.

A bug is not impossible either, though usually Dinotrace manages to eek out a warning message when it is about to lose a signal.

4.5 Why doesn’t a signal I can see in Dinotrace appear in the annotation?

Under the Value Annotate is a option menu which chooses which signals are included in the annotation. By default, deleted signals aren’t included. Often signals that are constant through the whole trace are deleted, and thus don’t get included in the annotation. Change the option to include deleted signals, or add the needed signals back.

4.6 Why do I get the wrong value for an annotated signal?

Because you know more than Emacs. (At least for the time being.) Emacs simply does a search and replace for the signal name, totally ignoring the bus bits, module name, and hierarchy.

First off, this means bus subscripts are ignored. The traced signal ‘foo[5:0]=6'b101010’ when annotating ‘foo[5]’ will show the value of the whole vector, not just bit 5: ‘foo`101010'[5]’.

Furthermore, having multiple signals with the same name will confuse things, as the hierarchy isn’t known. If the trace has the signals ‘[5:2]’ and ‘[5:2]’ with different values, and the code references foo, you could get either the a or b version. Your best bet is to delete the signals that don’t apply to the module you are annotating. (If a signal like the clock is in many modules, but identical, there’s nothing to worry about.)

5. Suggestions

5.1 Can Dinotrace directly read VCD+/VPD format files?

Nope, sorry. VCD+ is a proprietary format, and the reading code must be licensed for a fee before being used. This is obviously not possible with the distribution philosophy of Dinotrace.

You can however convert VCD+ files on the fly using vpd2vcd. See the documentation for details.

5.2 I’d like Dinotrace to...

Send a note to the author, I’ll see what I can do. As my time is limited, consider using the force, and editing the source.