PinPort
Application: Accurate Models
The
Challenge
You are
building a system out of package parts interconnected on a printed
circuit board (PCB). To verify the operation of the system prior
to designing and manufacturing the PCB, you want to use logic
simulation. You realize that this requires simulation models
for all of the parts on the PCB.
You checked
and you can get some of the models from semiconductor vendors.
Others you can get from sites off the web. A few are simple and
you can write them yourself. However, for two of the more sophisticated
parts you can find no models. Since these parts are the heart
of your system, you can't stub them out of the system simulation.
Because the parts are complicated, it would be too time-consuming
to write the models yourself.
Do you
abandon your system simulation plans? Will you do the first verification
of the integration of your system on a bread-board or do you
create the PCB and do it then? Do you hire someone to write the
models? If you hire someone to write the models, how will you
ensure that they are accurate? Are there other alternatives for
getting the needed simulation models?
The
Approach
By using
PinPort, the actual parts can be used to provide models in the
system simuilation.
Create
the Models
Mount
the part on an adapter board and insert the adaptor board into
a PinPort device. The PinPort device is connected to a workstation
through a SCSI interface. A Verilog logic simulator running on
the workstation communicates with the part through the PinPort
programming interface (a collection of Verilog PLI calls). A
Verilog wrapper module presents the pin interface of the part
to the test bench and communicates signal changes between the
testbench and the part by making PLI calls.
Add
Timing
If timing
is desired in the simulation of the PCB, the wrapper modules
are extended to incorporate it. These extensions take the form
of propagation delays on inputs, outputs, and/or between pins.
If you want to automatically check that timing conditions are
satisfied, you can add setup, hold, and pulse width checks. This
information is obtained from the databooks for the parts
Simulate
the System
You run
your system simulation with full confidence that all digital
parts are included in the simulation. You are assured that the
Verilog wrapper module / PinPort combinations provide 100% functionally
accurate models of two of your most complex parts. You use the
full interactive debugging capabilities of your simulator to
see signal values propagate between and through parts, regardless
of how they are modeled. You are pleasantly surprised that the
Verilog wrapper modules are evaluated by the simulator in a small,
relatively constant amount of time, even though the parts in
the PinPort are quite complex compared to most of the other parts
in the system.
The
Result
This application
of PinPort allows full system simulation with accurate and efficient
models for complex parts. These models are created without requiring
time-consuming model writing. The end result is that the system
is functionally verified before the PCB is completely designed
and built |
