Cadence Mixed-Signal Circuit Design Environment User Guide
Netlisting Options
October 2003
140
Product Version 5.0
An interface net has as many IEs as there are terminals on primitive digital instances
connected to the interface net. Interface split nets are created to reconnect primitive digital
instance terminals to the interface net so that the mixsim-verimix interface can store different
state values on these split nets. These interface split nets do not correspond to any actual
nets on the design.
Note: The design expansion done by the IE generator is not the same as the design
expansion done in the flat netlisting step. In FNL, the design expansion algorithm used by the
IE generator in detailed mode is similar to the design expansion step used by the FNL
netlister, but the algorithm used by the IE generator in non-detailed mode is different from the
design expansion step used by the FNL netlister.
Detailed IE generation improves the accuracy of simulation results (compared to non-detailed
IE generation) but reduces netlisting and simulation speed. Having too many interface
elements can slow down the analog simulator.
Detailed IE generation is necessary if each digital output pin on the net has a different driving
voltage or if each digital input pin on the net has a different threshold.
Note: Whenever the IE generator resolves a problem of multiple outputs or inputs on an
interface net because of non-detailed IE generation, the results of your simulation can be
inaccurate. Review these interface elements thoroughly.
FNL Testfixture File
The following shows the contents of an FNL
testfixture.template
file.
//timescale set according to user specification
`timescale 100ps / 100ps
//Begins test module definition.
module test
N1_00
N1_01
N1_10
N1_11
N1
N1
Original schematic
After IE insertion
Analog
block
Analog
block
D2A
D2A
A2D
A2D
Summary :
Cadence Mixed-Signal Circuit Design Environment User Guide Netlisting Options October 2003 140 Product Version 5.0 An interface net has as many IEs as there are terminals on primitive digital instances connected to the interface net. Interface split nets are created to reconnect primitive digital instance terminals to the interface net so that the mixsim-verimix interface can store different state values on these split nets.
Tags :
interface,design,net,fnl,expansion,different,generator,digital,nets,generation,used,analog,step