From owner-ibis Wed May 15 03:14:08 1996 Received: from alcatel.fr (ns.alcatel.fr [194.133.58.131]) by vhdl.vhdl.org (8.7.3/8.7.3) with ESMTP id DAA01389 for ; Wed, 15 May 1996 03:14:06 -0700 (PDT) Received: from alcatel.fr (gatekeeper-ssn.alcatel.fr [155.132.180.244]) by mailgate.alcatel.fr (8.7.3/8.7.3) with ESMTP id LAA09302 for ; Wed, 15 May 1996 11:06:59 +0200 Received: from ln.cit.alcatel.fr (las40304.ln.cit.alcatel.fr [155.132.225.2]) by nsfhh5.alcatel.fr (8.7.3/8.7.3) with SMTP id MAA00390 for ; Wed, 15 May 1996 12:04:50 +0200 (METDST) Received: from las41247.ln.cit.alcatel.fr by ln.cit.alcatel.fr (4.1/SMI-4.1) id AA09564; Wed, 15 May 96 12:04:50 +0200 Received: from las41247 (localhost) by las41247.ln.cit.alcatel.fr (4.1/SMI-4.1) id AA01376; Wed, 15 May 96 12:07:56 +0200 Sender: fitzpat1@ln.cit.alcatel.fr Message-Id: <3199ACFB.59E2B600@ln.cit.alcatel.fr> Date: Wed, 15 May 1996 12:07:55 +0200 From: FITZPATRICK John Organization: Alcatel CIT, 22304 Lannion, France X-Mailer: Mozilla 2.0 (X11; I; SunOS 4.1.3_U1 sun4c) Mime-Version: 1.0 To: ibis-users@vhdl.org Subject: Use of [Ramp] keyword Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hello all, A short question regarding interpretation of a model: In the IBIS 2.1 spec, the ramp rate is defined as dV 20% to 80% voltage swing -- = -------------------------------------- dt Time to take to swing the above voltage When I scan through a random set of IBIS models, I see the following entries after the [Ramp] keyword of the following types: a) dV/dt_r 1.84/0.65n 1.77/0.65n 1.87/0.53n b) dV/dt_r 4.1/1n 1.6/1n 8.2/1n From my point of view, a) is correct, but b) is not good. I would like to be able to extract dV and dt individually. As [Ramp] is an obligatory keyword, I hoped it would be safe to do so .... until I saw b). Thanks for your help, John -- John Fitzpatrick Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France Tel: (+33)96.04.79.33 Fax: (+33)96.04.85.09 From owner-ibis Wed May 15 07:51:24 1996 Received: from convex.convex.com (convex.convex.com [130.168.1.1]) by vhdl.vhdl.org (8.7.3/8.7.3) with SMTP id HAA09849 for ; Wed, 15 May 1996 07:51:18 -0700 (PDT) Received: from flare.convex.com by convex.convex.com (8.6.4.2/1.35) id JAA01211; Wed, 15 May 1996 09:41:34 -0500 Received: from localhost by flare.convex.com (8.6.4/1.28) id JAA09871; Wed, 15 May 1996 09:41:31 -0500 Date: Wed, 15 May 1996 09:41:31 -0500 From: schumach@flare.convex.com (Richard A. Schumacher) Message-Id: <199605151441.JAA09871@flare.convex.com> To: John.Fitzpatrick@ln.cit.alcatel.fr, ibis-users@vhdl.org Subject: Re: Use of [Ramp] keyword Agreed. It would be much more useful for users to be able to extract actual voltage swings and edge times from the "Ramp" data, and that is how "Ramp" is actually defined. "Ramp" must not be normalized in any way (for example, to volts per 1 nsec regardless of the actual edge time). Richard Schumacher I do not speak in any capacity for the Convex Division of the Hewlett Packard Company. From owner-ibis Wed May 15 08:22:48 1996 Received: from marceau.fm.intel.com (marceau.fm.intel.com [132.233.247.8]) by vhdl.vhdl.org (8.7.3/8.7.3) with ESMTP id IAA10086 for ; Wed, 15 May 1996 08:22:48 -0700 (PDT) Received: from fmmail.fm.intel.com by marceau.fm.intel.com (8.7.4/10.0i); Wed, 15 May 1996 15:08:43 GMT Received: from ccm.fm.intel.com by fmmail.fm.intel.com (Smail3.1.28.1 #2) id m0uJiDT-000rIQC; Wed, 15 May 96 08:10 PDT Received: by ccm.fm.intel.com (ccmgate 3.0) Wed, 15 May 96 08:10:19 PST Date: Wed, 15 May 96 08:10:19 PST From: Arpad Muranyi Message-ID: <960515081019_2@ccm.fm.intel.com> To: ibis-users@vhdl.org Subject: Re: Use of [Ramp] keyword Text item: John, This is an excerpt from the IBIS specification. It is from the section called "data derivation methods". | Then: Attach a 50 ohm resistor to GND to derive the rising edge | ramp. Attach a 50 ohm resistor to POWER to derive the | falling edge ramp. | | c. Due to the resistor, output swings will not make a full transition as | expected. However the pertinent data can still be collected as | follows: | 1) determine the 20% to 80% voltages of the 50 ohm swing | 2) measure this voltage change as "dV" | 3) measure the amount of time required to make this swing "dt" | | d. Post the value as a ratio "dV/dt". The simulation tool vendor | extrapolates this value to span the required voltage swing range in | the final model. According to this, your a) example might not be 100% correct, since it shows the same number for dt in the typical and minimum places. Usually the worst case buffer (represented in the minimum columns) will not be able to drive the load resistor as fast as a typical (or best case) buffer. So I would not expect to see two identical dt numbers in any of these entries. (However, I suspect you might have just forgotten to edit those numbers to make it look correct). Anyway, the b) example is definitely incorrect, since the numbers are "normalized" over 1 ns and do not follow the measurement rules quoted above. The simulator tool needs to know both numbers as would be measured according to the rules quoted above. If someone doesn't provide the numbers that way, there is actually loss of information. We had long discussions on this topic in the early days of the Open Forums. Arpad Muranyi Intel Corporation ================================================================================ Hello all, A short question regarding interpretation of a model: In the IBIS 2.1 spec, the ramp rate is defined as dV 20% to 80% voltage swing -- = -------------------------------------- dt Time to take to swing the above voltage When I scan through a random set of IBIS models, I see the following entries after the [Ramp] keyword of the following types: a) dV/dt_r 1.84/0.65n 1.77/0.65n 1.87/0.53n b) dV/dt_r 4.1/1n 1.6/1n 8.2/1n From my point of view, a) is correct, but b) is not good. I would like to be able to extract dV and dt individually. As [Ramp] is an obligatory keyword, I hoped it would be safe to do so .... until I saw b). Thanks for your help, John -- John Fitzpatrick Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France Tel: (+33)96.04.79.33 Fax: (+33)96.04.85.09 Text item: External Message Header The following mail header is for administrative use and may be ignored unless there are problems. ***IF THERE ARE PROBLEMS SAVE THESE HEADERS***. Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=us-ascii Subject: Use of [Ramp] keyword To: ibis-users@vhdl.org Mime-Version: 1.0 X-Mailer: Mozilla 2.0 (X11; I; SunOS 4.1.3_U1 sun4c) Organization: Alcatel CIT, 22304 Lannion, France From: FITZPATRICK John Date: Wed, 15 May 1996 12:07:55 +0200 Message-Id: <3199ACFB.59E2B600@ln.cit.alcatel.fr> Sender: fitzpat1@ln.cit.alcatel.fr Received: from las41247 (localhost) by las41247.ln.cit.alcatel.fr (4.1/SMI-4.1) id AA01376; Wed, 15 May 96 12:07:56 +0200 Received: from las41247.ln.cit.alcatel.fr by ln.cit.alcatel.fr (4.1/SMI-4.1) id AA09564; Wed, 15 May 96 12:04:50 +0200 Received: from ln.cit.alcatel.fr (las40304.ln.cit.alcatel.fr [155.132.225.2]) by nsfhh5.alcatel.fr (8.7.3/8.7.3) with SMTP id MAA00390 for ; Wed, 15 May 1996 12:04:50 +0200 (METDST) Received: from alcatel.fr (gatekeeper-ssn.alcatel.fr [155.132.180.244]) by mailg ate.alcatel.fr (8.7.3/8.7.3) with ESMTP id LAA09302 for ; W ed, 15 May 1996 11:06:59 +0200 Received: from alcatel.fr (ns.alcatel.fr [194.133.58.131]) by vhdl.vhdl.org (8.7 .3/8.7.3) with ESMTP id DAA01389 for ; Wed, 15 May 1996 03: 14:06 -0700 (PDT) Received: from vhdl.vhdl.org (vhdl.vhdl.org [198.31.14.3]) by ormail.intel.com ( 8.7.4/8.7.3) with ESMTP id DAA19342; Wed, 15 May 1996 03:08:51 -0700 (PDT) Received: from ormail.intel.com (ormail.intel.com [134.134.192.3]) by relay.jf.i ntel.com (8.7.4/8.7.3) with ESMTP id DAA11538; Wed, 15 May 1996 03:08:52 -0700 ( PDT) Return-Path: owner-ibis@vhdl.vhdl.org From owner-ibis Wed May 15 08:33:35 1996 Received: from ormail.intel.com (ormail.intel.com [134.134.192.3]) by vhdl.vhdl.org (8.7.3/8.7.3) with ESMTP id IAA10169 for ; Wed, 15 May 1996 08:33:34 -0700 (PDT) Received: from ichips.intel.com (ichips.intel.com [134.134.50.200]) by ormail.intel.com (8.7.4/8.7.3) with ESMTP id IAA10985 for ; Wed, 15 May 1996 08:24:22 -0700 (PDT) Received: from xtg801.intel.com by ichips.intel.com (8.7.4/jIII) id IAA11756; Wed, 15 May 1996 08:20:00 -0700 (PDT) Received: from localhost by xtg801.intel.com (4.1/SW1.11) id AA13722; Wed, 15 May 96 08:24:21 PDT Message-Id: <9605151524.AA13722@xtg801.intel.com> To: ibis-users@vhdl.org Subject: Use of [Ramp] keyword Date: Wed, 15 May 1996 08:24:20 -0700 From: Stephen Peters Hello John: Yes, I agree that example b) is an incorrect IBIS model. The intent of the [Ramp] keyowrd is to specify the *actual* amount of time it takes for the output to transition from one state to another, not simple give some edge rate. Regards, Stephen Peters Intel Corp. Hello all, A short question regarding interpretation of a model: In the IBIS 2.1 spec, the ramp rate is defined as dV 20% to 80% voltage swing -- = -------------------------------------- dt Time to take to swing the above voltage When I scan through a random set of IBIS models, I see the following entries after the [Ramp] keyword of the following types: a) dV/dt_r 1.84/0.65n 1.77/0.65n 1.87/0.53n b) dV/dt_r 4.1/1n 1.6/1n 8.2/1n >From my point of view, a) is correct, but b) is not good. I would like to be able to extract dV and dt individually. As [Ramp] is an obligatory keyword, I hoped it would be safe to do so .... until I saw b). Thanks for your help, John -- John Fitzpatrick Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France Tel: (+33)96.04.79.33 Fax: (+33)96.04.85.09 From owner-ibis Wed May 15 08:43:42 1996 Received: from relay5.UU.NET (relay5.UU.NET [192.48.96.15]) by vhdl.vhdl.org (8.7.3/8.7.3) with ESMTP id IAA10240 for ; Wed, 15 May 1996 08:43:42 -0700 (PDT) Received: from uucp5.UU.NET by relay5.UU.NET with SMTP (peer crosschecked as: uucp5.UU.NET [192.48.96.36]) id QQapva08329; Wed, 15 May 1996 11:34:14 -0400 (EDT) Received: from qdt.UUCP by uucp5.UU.NET with UUCP/RMAIL ; Wed, 15 May 1996 11:34:52 -0400 Received: from hal.qdt.com by qdt.com (4.1/SMI-4.1) id AA00533; Wed, 15 May 96 08:12:34 PDT Received: from qdt.com by hal.qdt.com (4.1/SMI-4.1) id AA01946; Wed, 15 May 96 08:12:33 PDT Received: from uucp3.UU.NET by relay5.UU.NET with SMTP (peer crosschecked as: uucp3.UU.NET [192.48.96.34]) id QQapuy00387; Wed, 15 May 1996 11:05:58 -0400 (EDT) Received: from qdt.UUCP by uucp3.UU.NET with UUCP/RMAIL ; Wed, 15 May 1996 11:05:58 -0400 Received: from hal.qdt.com by qdt.com (4.1/SMI-4.1) id AA00444; Wed, 15 May 96 07:47:12 PDT Received: from f14.qdt.com by hal.qdt.com (4.1/SMI-4.1) id AA01781; Wed, 15 May 96 07:47:11 PDT Date: Wed, 15 May 96 07:47:11 PDT From: uunet!qdt.com!jonp@uunet.uu.net (Jon Powell) Message-Id: <9605151447.AA01781@hal.qdt.com> Received: by f14.qdt.com (4.1/SMI-4.1) id AA14342; Wed, 15 May 96 07:47:10 PDT To: uunet!uunet!ln.cit.alcatel.fr!John.Fitzpatrick@uunet.uu.net Cc: uunet!uunet!vhdl.org!ibis-users@uunet.uu.net In-Reply-To: <3199ACFB.59E2B600@ln.cit.alcatel.fr> (uunet!ln.cit.alcatel.fr!John.Fitzpatrick) Subject: Re: Use of [Ramp] keyword >>>>> "FITZPATRICK" == FITZPATRICK John writes: FITZPATRICK> Hello all, A short question regarding interpretation FITZPATRICK> of a model: FITZPATRICK> In the IBIS 2.1 spec, the ramp rate is defined as FITZPATRICK> dV 20% to 80% voltage swing -- = FITZPATRICK> -------------------------------------- dt Time to FITZPATRICK> take to swing the above voltage FITZPATRICK> When I scan through a random set of IBIS models, I FITZPATRICK> see the following entries after the [Ramp] keyword of FITZPATRICK> the following types: FITZPATRICK> a) dV/dt_r 1.84/0.65n 1.77/0.65n 1.87/0.53n FITZPATRICK> b) dV/dt_r 4.1/1n 1.6/1n 8.2/1n >> From my point of view, a) is correct, but b) is not good. FITZPATRICK> I would like to be able to extract dV and dt FITZPATRICK> individually. As [Ramp] is an obligatory keyword, I FITZPATRICK> hoped it would be safe to do so .... until I saw b). FITZPATRICK> Thanks for your help, John You are right, b is probably meaningless (unless the risetime happens to be 1ns. What model was this in? Jon From owner-ibis Wed May 15 10:01:51 1996 Received: from alcatel.fr (ns.alcatel.fr [194.133.58.131]) by vhdl.vhdl.org (8.7.3/8.7.3) with ESMTP id KAA12302 for ; Wed, 15 May 1996 10:01:49 -0700 (PDT) Received: from alcatel.fr (gatekeeper-ssn.alcatel.fr [155.132.180.244]) by mailgate.alcatel.fr (8.7.3/8.7.3) with ESMTP id RAA16087; Wed, 15 May 1996 17:54:27 +0200 Received: from ln.cit.alcatel.fr (las40304.ln.cit.alcatel.fr [155.132.225.2]) by nsfhh5.alcatel.fr (8.7.3/8.7.3) with SMTP id SAA29802; Wed, 15 May 1996 18:52:20 +0200 (METDST) Received: from las41247.ln.cit.alcatel.fr by ln.cit.alcatel.fr (4.1/SMI-4.1) id AA13858; Wed, 15 May 96 18:52:21 +0200 Received: from las41247 (localhost) by las41247.ln.cit.alcatel.fr (4.1/SMI-4.1) id AA01635; Wed, 15 May 96 18:55:25 +0200 Sender: fitzpat1@ln.cit.alcatel.fr Message-Id: <319A0C7C.41C67EA6@ln.cit.alcatel.fr> Date: Wed, 15 May 1996 18:55:24 +0200 From: FITZPATRICK John Organization: Alcatel CIT, 22304 Lannion, France X-Mailer: Mozilla 2.0 (X11; I; SunOS 4.1.3_U1 sun4c) Mime-Version: 1.0 To: ibis-users@vhdl.org Cc: Sri Jandhyala Subject: Thanks (Re: Use of [Ramp] keyword) References: <960515081019_2@ccm.fm.intel.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Hello all, Thanks to everyone who replied to my question. It looks like I'm slowly getting to understand the spec! The general view is that b) is indeed wrong. Example b) is an LVT18504 model that Sri Jandhyala (TI) sent me a few months ago when I was interested in seeing how bus-hold can be modelled. Example a) is from the CMOS_I/O buffer of Pentium(R)_Pro_Processor, pentpro.ibs, revision 2.1. I was interested by Arpad's remark that the "a) example might not be 100% correct, since it shows the same number for dt in the typical and minimum places." As the pentpro has rising and falling waveforms, I guess I should really use them instead of relying on [Ramp]. Thanks again for your help. John ps Is it possible to search the mail archive? I may have other such questions that were surely answered long before I got to know about IBIS --------------------------------------------------------- Hello all, A short question regarding interpretation of a model: In the IBIS 2.1 spec, the ramp rate is defined as dV 20% to 80% voltage swing -- = -------------------------------------- dt Time to take to swing the above voltage When I scan through a random set of IBIS models, I see the following entries after the [Ramp] keyword of the following types: a) dV/dt_r 1.84/0.65n 1.77/0.65n 1.87/0.53n b) dV/dt_r 4.1/1n 1.6/1n 8.2/1n >From my point of view, a) is correct, but b) is not good. I would like to be able to extract dV and dt individually. As [Ramp] is an obligatory keyword, I hoped it would be safe to do so .... until I saw b). Thanks for your help, John -- John Fitzpatrick Alcatel CIT, 4 rue de Broglie, 22304 Lannion, France Tel: (+33)96.04.79.33 Fax: (+33)96.04.85.09