Cadence Tutorial
Spectre Netlist Simulation - Graphical
Interface
Authors: David
Donofrio, Jos Sulistyo, Meenatchi Jagasivamani and Carrie Aust
This tutorial explains how to simulate
your extracted Spectre netlist using Analog Artisit (graphical interface).
To simulate using spectre from the command line go to spectre simulation from the command
line
Netlist Simulation
Procedure when starting from Composer (schematic netlist):
- From Analog
Artist:
- Choose
Setup->Simulator/Directory/Host
- Set Spectre to be the
current simulator
- Project Directory
is top level simulation work directory (cadence will create multiple
subdirectories under this one)
- Choose
Setup->Model
Path
- Type full path
(including filename) of any model(s) needed for
simulation
- NOTE: The
default model specified by Composer is d25.m (download
it!).
If you wish to change
this model name, it must be done in Composer by displaying an
objects properties (Select object, press 'q' shortcut, change "Model
Name" field - note that the '.m.' extension is implied)
- Choose
Outputs -> To
be plotted . . . -> Select on Schematic
- Schematic window
will come to the foreground.
- Click on any
signals (i.e. the WIRE) you wish to plot, you will see the wire change
color once it is selected
- Choose
Analysis ->
Choose
- Choose your
desired Analysis
Example: Transient analysis, choose 'tran' and then
type in the total time you wish to run (ex. 40n or
40e-9)
- Choose
Setup ->
Stimuli
- A window will
appear where you may graphically set up the stimulus
signals
Once you are done
setting up a signal, choose "change"
- NOTE: if you do
NOT wish to stimulate a node that has been declared as
input/output
be sure to disable it by un-selecting "enabled."
- Click the Green
Traffic Light Icon (bottom right corner of Analog Artist) to run the
simulation
If no
warnings or errors occur, the simulation will run and all requested signals will
be plotted
Netlist Simulation
Procedure when starting from Virtuoso (layout netlist):
From
Analog Artist:
- Choose Setup->Simulator/Directory/Host
- Set Spectre to be the
current simulator
- Project Directory is
top level simulation work directory (cadence will create multiple
subdirectories under this one)
- Choose Setup->Model
Path
- Type full path
(including filename) of any model(s) needed for simulation
- NOTE: The
default model specified by Virtuoso is d25.m
(download it!).
- Choose Analysis ->
Choose
- Choose your desired
Analysis
Example: Transient analysis, choose 'tran' and then
type in the total time you wish to run (ex. 40n or
40e-9)
- Click the Green
Traffic Light Icon (bottom right corner of Analog Artist) to run the
simulation
If no warnings or errors occur, the
netlist will be extracted and displayed.
- The file generated by
Analog Artist at this point is ready, once the inputs are stimulated., to be
simulated by Spectre. In
order to stimulate the inputs it is necessary to manually edit the file
generated by Analog Artisit and add the stimiulus
commands into the file. This can be done with any
simple text editor, such as vi.
- The file inverter.scs is an example of the output
generated by Analog Artist for an extracted
inverter layout with the
necessary commands to stimulate the inputs added. The models used in this
example may be found in the file d25.m (download
it!).
From the
command line:
- After you have completed all the
steps from within Analog Artist listed above:
- Switch to the directory where
spectre has placed your resulting netlist (will be given at the bottom of the
Analog Artist window)
- Open the netlist file (typically
input.scs) and add the necessary stimilus commands, if you have not done so
already.
The file inverter.scs is an example of the output
generated by Analog Artist for an extracted inverter layout with the
necessary commands to stimulate the inputs added.
- To peform spice simulation, type the
command.
spectre inverter.scs
(where
'inverter.scs' is the name of the netlist file generated by Analog
Artist)
- To plot the results, type the
command.
awd -dataDir
inverter.raw/ (where 'inverter' is the
name of the netlist file generated by Analog Artist)
NOTE: for the above to
work, make sure inverter.scs is in your current working directory.
Four windows appear.
Activate
"Result Browser" window.
- Click left buton on
input.raw
Yellow node numbers show up on the
right end of the hierarchy.
- Clcik right button on any nodes you wish to
display.
"Waveform Window" displays the
waveform.
- To make a hard copy of the
plot
- Choose hardcopy menu from
Windows menu on "Waveform Display" window.
A windows appears.
- Verify Laser Writer is chosen as
"Plotter Name".
- Click "Send Plot Only to File.,"
and type in the file name. Click apply to generate a postscript
file.
Additional
Info:
For details of
Spice and Spectre, refer to the online manuals. They can be opened as:
cdsdoc
&
Choose the
following menus in the sequence.
IC Tools -> Analog and Mixed Signal
Simulation
-> For SPICE choose "HSPICE/SPICE Interface ..."
-> For
Spectre choose "Spectre User Guide."
IMPORTANT:
There must be one blank line at
end of file. Spectre is case-sensitive.
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