u nodename x nodename clock node val vectoe label nodes set vector value clear q Make node logic unknown input Removes nodes from input lists Define sequence of value for clock node Define bit vector Assign value to vectoe Clear analyzer windows Quit Typical command file for the example inverter circuit inv cmd would look like the following ana Vin Vout stepsize 20 l Vin s h Vin s l Vin s h Vin s After adding the commands save the command file 4 Starting up IRSIM To startup IRSIM type in at the unix prompt irsim prm file sim file where prm file hp cmos26g prm if 0 8um tech is being used scmos2um prm if 2um tech is beng used Example unix prompt irsim hp cmos26g prm inv sim Startup IRSIM for the file inv sim IRSIM version 9 3 prob4a sim Ignoring lumped resistance R construct 9 nodes transistors n channel 5 p channel 5 parallel txtors none irsim irsim inv cmd Open the command file inv cmd The analyzer window opens up displaying the signals defined in the command file irsim q Quit from irsim IRSIM Handout Spring 1998 EE577a IRSIM is an event driven logic level simulator for MOS both N and P transistor circuits Two simulation models are available SWITCH Each transistor is modeled as a voltage controlled switch Useful for initializing or determining the functionality of the network We shall be using this model extensively to verify functionality of the circuits that are designed for this class LINEAR Each transistor is modeled as a resistor in series with a voltage controlled switch Each node has a capacitance Node values and transition times are computed from the resulting network using Chorng Yeoung Chu s model RC Chris Terman s original model is not supported any more The prm file is the parameter file that configures the devices to be simulated The hp cmos26g prm for scmos sub 0 8 micron technology and scmos2um prm for 2 um technology files shall be used IRSIM ANALYZER The analyzer provides a graphical interface to irsim displaying the state of the nodes or vectors Every invocation of the command adds a new set of signals to the display list The view is split into 3 regions a trace window a text window and a banner The banner displays the name of the simulation from the sim file and the menu headers The text window is a 1 line window used to request and display certain information The trace window displays the following information names of the signals nodes vectors is displayed On the left and right sides the time corresponding to the left and right edges of the trace window are displayed and in the center the time of the current position Steps for using IRSIM 1 If you did setup according to Magic handout then you don t have to do any setup for IRSIM 2 Converting ext file to irsim file To convert the ext file obtained from magic layout type at the unix prompt ext2sim t filename without any extension Filename sim file is created 3 Making Command file for IRSIM Create a file called filename cmd ex inv cmd where a file called inv sim exists and include commands in this cmd file by using any editor e g emacs vi pico The following is a summary of basic commands that can be added to the command file For other commands refer the CAD Tools Tutorial IRSIM section Command Summary filename cmd ana nodename stepsize n s n takes command from the command file display nodes in analyzer window set simulation stepsize to n ns simulate for n ns default stepsize c n l nodename h nodename Simulate n clock cycles Make node logic low 0 input Make node logic high 1 input