Piped and Non-Piped Simulations

The following sections describe the differences in piped and non-piped simulations for the various SPICE simulators. Each section also describes the argument syntax required to invoke each of the template simulators. This information is needed when writing the user translation module, since these are the arguments supplied by IC-CAP when it calls the translation module. For information on the translation module and adding a simulator, refer to the section "Adding a Simulator" in the User's Guide.

Piped and Non-Piped SPICE Simulations

A non-piped simulation receives the input deck information from a file, performs the simulation and sends the binary output data and resulting text output to other files. The simulator process is restarted for every simulation.

A piped simulation receives the input deck information from a pipe connected to standard input, performs the simulation and sends the output data to a pipe connected to standard output. The simulator process will remain on until another simulator is selected. Setting the RETAIN_SIMU variable to TRUE overrides this behavior and allows multiple simulators to remain running. This uses additional memory but increases speed when frequently switching between simulators. In all cases, a piped simulator process will be turned off when the Simulation Debugger is turned on.

The text output from a simulation usually contains an explanation of any errors which may have been encountered during the simulation. Piped simulations do not save any text output from the simulation. If an error occurs during a piped simulation, IC-CAP issues a message in an error box stating that an error has occurred and recommending that the simulation be repeated with the Simulation Debugger turned on. IC-CAP performs non-piped simulations when the Simulation Debugger is ON.

In general, piped simulations are faster than non-piped simulations for any given simulator because the simulator process does not have to be restarted for every simulation and less file activity is required.

Syntax: Non-Piped 2G.6, 3E2, and HPSPICE Simulations

The command formats for non-piped simulations are shown next:

UCB SPICE 2G.6

 ucbspice2g6 rawfile 

where:

rawfile is the output binary data file.

The input deck file containing the circuit description and analysis commands comes from standard input and the output text file containing the results of the simulation goes to standard output.

UCB SPICE 3E2

 spice3e2 -b -r rawfile -o textfile deckfile 

where:

-b specifies batch mode.

rawfile is the output binary data file.

textfile is the output text file containing the results of the simulation.

deckfile is the input deck file containing the circuit description and analysis commands.

HPSPICE

 spice2.4n1 deckfile textfile rawfile 

where:

deckfile is the input deck file containing the circuit description and analysis commands.

textfile is the output text file containing the results of the simulation.

rawfile is the output binary data file.

Syntax: Piped 2G.6, 3E2, and HPSPICE Simulations

The command formats for piped simulations are shown next:

UCB SPICE 2G.6

 ucbspice2g6 - 

where:

The "-" denotes that the binary data output is going to the standard output pipe. The input deck information comes from the standard input pipe and the output text is sent to the file /dev/null.

UCB SPICE 3E2

 spice3e2 -s 

where:

The -s option specifies that the input deck information is coming from standard input and the binary data output is going to standard output.

HPSPICE

 spice2.4n1 - /dev/null - 

where:

The first "-" denotes that the input deck information is coming from the standard input pipe.

The output text is sent to the file /dev/null.

The last "-" denotes that the binary data output is going to the standard output pipe.

Non-Piped HSPICE Simulations

Non-piped HSPICE simulations are identical to non-piped SPICE simulations. This type of simulation is performed when the Simulation Debugger is set to ON. If CANNOT_PIPE is specified for HSPICE, even when the Simulation Debugger is OFF, it still performs a non-piped simulation. This means that HSPICE must be restarted for every simulation. Because of this, there is no noticeable difference in simulation speed when the Simulation Debugger is set to ON or OFF.

Syntax: Piped HSPICE Simulations

The command format for an HSPICE piped simulation is as follows:

hspice -I

load deckname and run commands are then passed to the running HSPICE process.

Syntax: Non-Piped HSPICE Simulations

The command format for an HSPICE non-piped simulation is as follows:

hspice -i deckfile -o logfile 

where

deckfile is the input deck file containing the circuit description and analysis commands.

logfile is the listing of information about the simulation generated by HSPICE. If the simulation debugger is open, this file will be displayed in the Output Text portion of the simulation debugger.

The output binary data file is written to a file named deckfile.suffix where suffix depends on the type of analysis being performed. Refer to the HSPICE User's Manual for more information.

Syntax: Client/Server mode HSPICE Simulations

On Windows, provides a method of invoking a standing server process to access HSPICE licenses. If this was launched via the hspui program, IC-CAP can simulate faster by launching HSPICE with the followin syntax:

hspice -C deckfile -o logfile 

where

deckfile is the input deck file containing the circuit description and analysis commands.

logfile is the listing of information about the simulation generated by HSPICE. If the simulation debugger is open, this file will be displayed in the Output Text portion of the simulation debugger.

However, if the server has not been started, the simulation still occurs but at a slower speed.

To configure IC-CAP to send the -C instead of -i, specify the template name hspice-C as the second field in your usersimulators line example:

 hspiceC hspice-C c:\synopsys\Z-2007.09\bin\hspice.exe "" 
CANNOT_PIPE

Non-Piped ELDO Simulations

Non-piped ELDO simulations are identical to non-piped SPICE simulations. This type of simulation is performed when the Simulation Debugger is set to ON. ELDO is not capable of performing a piped simulation, so even when the Simulation Debugger is OFF, it still performs a non-piped simulation. This means that ELDO must be restarted for every simulation. Because of this, a there is no noticeable difference in simulation speed when the Simulation Debugger is set to ON or OFF.

Syntax: Non-Piped ELDO Simulations

The command format for an ELDO non-piped simulation is as follows:

 eldo deckfile 

where

deckfile is the input deck file containing the circuit description and analysis commands. The name of this deckfile is in the form <circuit_name>.cir.

The output binary data file is written to a file named <circuit_name>.spi3. This output binary data format is similar to the output binary format of the UCB SPICE3 simulator and is generated when you specify the option

  .option spi3bin 

Refer to the ELDO User's Manual for more information.

The output text file, is sent to the file named <circuit_name>.chi This file is displayed in the Output table of the Simulation Debugger if it is on.