TA Page Home

Accessing vlsicad

CAD Tools Setup

Design Flow

Selected Links

CAD tools demos

HSPICE tutorial

HSPICE & CSCOPE Quick Tutorial

Here is a brief review of the steps required for running HSPICE and CSCOPE on vlsicad.

1.      Start Xming

2.      Use SSH to connect to your account at username@vlsicad.ecs.umass.edu

3.      Change dir to vlsix

4.      Generate your SPICE file using text editor

5.      Run HSPICE    vlsicad:> hspice filename.spice

6.      Run CScope using vlsicad:> cscope 

Here is an example of a simple RC circuit file where a step input is applied to R1:

image2

HSPICE input file for the circuit is given below where .MEASURE statement use used to measure the propagation delay from the step input at node ‘a’ to a 50% rise in voltage at node ‘b’.

* Simple RC circuit

.OP

.OPTION POST

R1 1 2 1K                          * Resistance

C1 2 0 1uF                         * Capacitnace

V1 1 0 PWL (0s 0V 2ms 0V 2.001ms 1V 10ms 1V)     * piece wise linear waveform

.TRAN 1us 10ms                                   * Transient analysis till 10ms

* Measure delay from v(1) to v(2)

.MEASURE TRAN td TRIG=v(1) VAL=0.5 RISE=1 TARG=v(2) VAL=0.5 RISE = 1

.END

 

Perform the following steps:

1.       The file is stores as rc_circuit.spice

2.       Run hspice vlsicad:> hspice rc_circuit.spice > rc_circuit.log. It will generate rc_circuit.tr0 file and an rc_circuit.mt0 file. rc_circuit.tr0 contains the waveform information to be viewed in CScope and rc_circuit.mt0 contains the time value measured by .MEASURE statement. Check the rc_circuit.log file to see if the simulation concluded or was aborted.

3.       Start CScope by using vlsicad:> cscope command. In CScope open the file rc_circuit.tr0 to view the waveforms and make manual measurement

image6

1.       The propagation time is obtained as 692us from the rc_circuit.mt0 file and 697.5us from manual measurement. The more accurate value is the one obtained from HSPICE.