( ESNUG 319 Item 9 ) --------------------------------------------- [5/26/99]
From: "Jim Avant" <javant@homewireless.com>
Subject: Are There No Waveform Viewers For DSP & Ram Intensive Designs?
John,
We've been auditioning simulators and stand-alone waveform viewers and
I've identified a couple of common holes in the feature lists. I thought
that maybe some of your subscribers may be able to help. Or at least let
me know if I'm the only one who cares.
I do a lot of DSP verilog code development and I'd like to be able to
right click on a signal and format the signal as analog AND as 2's
complement. Furthermore I'd like to be able to scale and offset the
resulting waveform as well as control the height of the field allocated
for its display. I'd also like to be able to independently change the
color of this signal.
I've found several waveform viewers that each do part of this (ModelSim
comes closest but doesn't understand sign-magnitude vs. 2's complement).
Of course the work-around is to create code in your testbench which
dredges up signals buried in the hierarchy and reformat the signals for
display (this is not even possible with some waveform viewers).
The other thing I want to do but haven't found anything close is to view
the contents of a RAM at the time selected by the cursor in the waveform
display window. This should be a separate display window with a column
for address on the left side and data laid out to the right. A new row
should start every 8 data items but if you stretch the window wide enough,
it should change to every 16 data items. Of course there should be
features in this view such as scroll bars and the ability to search for a
pattern. There are ample examples of how this should work in logic
analyzers, device programmers, etc.
I realize that this could be very compute/time intensive especially for
large memories. But in DSP designs, you often have lots of small memories
or register files to keep track of. I'd like to be able to open several
"memory monitor" windows and see the contents change as simulation time
progresses (or turn off updating to speed up the simulation).
I know I can write a PLI to do some if not all of this but it seems to me
that this is a feature that should be incorporated into the waveform
viewer and that many designers could make use of this.
Am I the only one who's asking for these features? Are there any
relatively painless work-arounds that anyone has found?
- Jim Avant
Home Wireless Networks
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