Hi Bob, Simply put, you will be better served utilizing scheme B. If in fact your timing is tight long runs of ones or zeros followed by a single instance of the opposite may yield longer timing that could cause you problems. A pseudo random sequence can help model this behavior. If your tool limits you to only a pulse imput, you may wish to extend the period of the pulse in order to get a true picture of the settling time. Be careful about sweeping statements about buses not running at the rate of the clock. In todays world of dual edge clocking and multi-level signalling, things may actually 'worse' than simply toggling at the rate of the clock. When working through your timing calculations, remember that clock to out on the device is specified in a given test load. Adding your simulated flight time number to this test load number will give an overly large number which may indicate set up times are violated when they aren't or that hold time is OK when it isn't. A number of the tools have the ability to subtract out this number, but if you are doing things manually you need to be aware of this. I hope that this helps. MG -----Original Message----- From: Bob Patel [mailto:whizplayer@xxxxxxxxx] Sent: Tuesday, October 16, 2001 10:31 PM To: si_list Subject: [SI-LIST] Address bus simulation Hi! I don't know if the above topic was discussed before because I could not find it in the archives on a quick scan. Say, we need to do find out whether we can run the address bus to two loads in Star configuration with clock at 200Mhz. Now, first the address bus will be not running at this frequency clock frequency. So, in terms of simulation what should be the approach a) Run simulation with pulse source at 200Mhz--->Not true picture b)Run simulation with random bit pattern? I want to know what would be appropriate in simulating this? Thanks in advance Bob __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals. http://personals.yahoo.com ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu