Hi, Nitin, Driver Schedule is a time scheduling function in the simulation. It can be used for a time scheduling purpose which could contain more than one buffer turn-rise/fall inside time period it describes. We can use this feature (different buffers) for different pre-emphasis levels and schedule the time for them turn-rise/fall. This is the basic concept to use for two tap pre-emphasis. It should be able to for multi-tap pre-emphasis as well. Driver schedule has the limitation for changing pre-emphasis level or bit width. You will have to change it manually or using different Driver Schedule settings. So you will need to dig in your application to find out if it can satisfy your requirement. Spice macromodeling is the same or almost the same approaches as Arpad's. Compare to AMS (especially VHDL-AMS). However, it almost totally removes the simulator dependency as you described in your email. Spice modeling with IBIS buffers can be used in almost all the big name simulators (HSpice, Eldo, Cadence's, SiSoft's, Sigrity's, Ansoft's, and many, many more. Sorry if I did not mention yours.). And many internal Spice simulators can do that as well. (I will let others tell you.) And I have to tell you sadly as an IBIS lover, compare to IBIS Driver Schedule implementation in the Spice simulator, Macromodling required functions (mainly parameter passing) are much, much better in these simulators. This is a huge advantage to your customers. In recent high-speed designs, many channels still only need to have pre-emphasis driver to open eyes. It does mean that they can use your chip (model) to design the new product without extra cost of a new tool. Hope this helps, Lance Wang IO Methodology Inc. SIMDE™ V1.0 – Signal Integrity Model Development Environment The complete IBIS / Spice Macromodel generation and validation tool www.iometh.com/Product/SIMDE -----Original Message----- From: Nitin Kumar CHHABRA [mailto:nitin.chhabra@st.com] Sent: Thursday, July 23, 2009 1:28 AM To: 'Lance Wang'; twesterh@sisoft.com; Arpad_Muranyi@mentor.com Cc: ibis@server.eda.org; si-list@freelists.org; 'Nitin GUPTA'; 'Vishrant GOYAL' Subject: RE: IBIS model of differential driver with programmable multi-tap preemphasis Hi Arpad, Thanks for your valuable input. You are right that I need the pure analog environment for simulation and so IBIS-AMI/IBIS-AMS were not taken in account. Since Input pattern is also unknown I could not use driver-scheduling. The example approach you gave is exactly what we had followed, only difference being I used ELDO-2009 for stimulus generation in place of HSPICE. But still the relationship of those signals was outside IBIS world and is simulator dependent. We wanted to make IBIS model which could be used by any common simulator for analysis. Inside the IBIS file only, is there any method to cascade different models i.e. output of one model becomes input to other and so on. Hi Tod, This is HDMI transmitter with multilevel tap-pre-emphasis , so IBIS-AMI is not good solution. Hi lance, I am still not sure how to use Driver scheduling in this case. The input pattern could change and depending on that pattern the required pre-emphasis level could be activated. Depending on history of previous bits, the particular level of tap is activated and pre-emphasis strength changes. Could you please elaborate how to use driver scheduling in that case. Spice macro-modeling is one of the best approaches for the same and almost same as what Arpad had explained in his example. Thanks and regards, Nitin -----Original Message----- From: si-list-bounce@freelists.org [mailto:si-list-bounce@freelists.org] On Behalf Of Lance Wang Sent: Wednesday, July 22, 2009 8:49 PM To: ibis@server.eda.org; si-list@freelists.org Subject: [SI-LIST] Re: [ibis-macro] IBIS model of drifferential driver with programmable multi-tap preemphasis Nitin, Additional to Arpad's comments: There is a possibility to use Driver Schedule for multi-tap pre-emphasis buffer modeling. I did a presentation in 2005 and showed it works for 4 tap in the presentation below: (page 41) http://www.vhdl.org/pub/ibis/summits/mar05j/wang.pdf Also, you could do Spice-macromodeling with IBIS buffer models for pre-emphasis. The benefits for it are faster and can be used in the most of Spice simulators. Users will not be requested to cost more for new tools. http://iometh.com/Product/SIMDE/Macromodeling.pdf http://www.vhdl.org/pub/ibis/summits/oct06b/wang.pdf Hope this helps, Lance Wang IO Methodology Inc. SIMDET V1.0 - Signal Integrity Model Development Environment The complete IBIS / Spice Macromodel generation and validation tool www.iometh.com/Product/SIMDE -----Original Message----- From: si-list-bounce@freelists.org [mailto:si-list-bounce@freelists.org] On Behalf Of Muranyi, Arpad Sent: Wednesday, July 22, 2009 10:54 AM To: ibis@server.eda.org; si-list@freelists.org Subject: [SI-LIST] Re: [ibis-macro] IBIS model of drifferential driver with programmable multi-tap preemphasis Nitin, If you have access to the stimulus, you could pull this off with the Driver Schedule or even without it, but that would be a semi official IBIS solution because it may not work in all tools. For example, if you do it with the HSPICE B-element, you could make a B-element for each stage of your buffer, and then make a special stimulus generator which reproduces the bit pattern dependent waveforms for the input to each B-element (buffer stage). This way the stages of your buffer would still be IBIS models, but the relationship between them would be outside the IBIS world. Another way to do it would be to use the *-AMS extensions of IBIS. This way you could make a completely official model for the entire buffer. However, not all IBIS tools have implemented the *-AMS extensions of IBIS, although there are several tools with Verilog-A support which may be sufficient for what you want to do. I hope this helps. Arpad =============================================================== -----Original Message----- From: ibis-macro-bounce@freelists.org [mailto:ibis-macro-bounce@freelists.org] On Behalf Of Nitin Kumar CHHABRA Sent: Wednesday, July 22, 2009 7:14 AM To: ibis@server.eda.org; si-list@freelists.org Cc: vishrant.goyal@st.com; nitin.chhabra@st.com; nitin.gupta@st.com Subject: [ibis-macro] IBIS model of drifferential driver with programmable multi-tap preemphasis Hi experts, We want to develop the IBIS model for a differential driver with pre emphasis . The driver has three tap with programmable pre emphasis options. Does anyone came across such IBIS or could provide some IDEA how to proceed for the same. Using Driver Scheduling, we are able to make model for first tap pre emphasis buffer. But we cannot accommodate the second and third tap options as they require previous bit histories. with regards, Nitin --------------------------------------------------------------------- IBIS Macro website : http://www.eda.org/pub/ibis/macromodel_wip/ IBIS Macro reflector: http://www.freelists.org/list/ibis-macro To unsubscribe send an email: To: ibis-macro-request@freelists.org Subject: unsubscribe ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@freelists.org with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@freelists.org with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: http://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@freelists.org with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@freelists.org with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: http://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 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org |with the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Thu Jul 23 13:55:07 2009
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