You're trying to sweep an output pin that is driving high. My guess is either: (1) you connected the curve tracer to a 5V power pin by mistake; or (2) the current scale on the curve tracer is set much too sensitive. If it's set to show you nanoamps or microamps full-scale, the voltage is not going to move noticeably from 5V. Set the curve tracer so that it shows you at least tens of milliamps full-scale. Regards, Andy > Sounds like you may have a slight current leak or resistive pullup in your > device. The DMM, being very hi impedance will read a high. Putting the > curve tracer on it shows no current. Try loading the output with a 1K > resistor when using the DMM. This will tell you if you really have a high. ... >> I am a newbie to the world of IBIS modelling. Recently, I've tried to curve >> trace an I/O at a high state. When verified using a multimeter the pin >> confirms to output high. However when I try to curve trace this particular >> pin, I get a dead straight line at 5V (Vdd is powered at 5V). Where did I go >> wrong? ------------------------------------------------------------------ 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