Kumar,A standard way of identifying which of various equalization types are being used would be nice. Certainly classical FFE and DFE could be indicated, allowing the EDA platform to perform intelligent optimization or "dithering" of the tap parameters for sensitivity studies outside the boundaries of what the silicon provides. I can see this as valuable for a silicon vendor, during compliance verification, and during robustness analysis of a system. (Personally I hate optimizations that have the potential to be unstable with slight errors that occur from those un-modeled, or improperly modeled, demons. Experience dictates that any particular model is only an imperfect approximation of the silicon. As a system designer, I like to stress models outside of their normal limits.) A silicon vendor that has a proprietary equalization scheme, or does not want to reveal the details, could use a type of UNKNOWN. Future methods, including analog methods, could also be easily added with the same construct.
If the AMI model is truly a "black box" there is no need to pass unknown parameters at all. By definition, a black box is a closed system with well-defined inputs and outputs. User-defined taps, without further documentation, would not be well-defined in my estimation. Thus, if the EDA platform is going to pass Taps back and forth, more standardized knowledge should be included in the description than is found in model comment lines or help files. If a silicon vendor does not want to reveal the equalization technique used by their "black box", then there is no need to define taps at all, or pass them through the EDA tool.
best regards, Scott -- Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC ckumar@xxxxxxxxxxx wrote:
if the model allows for user defined inputs it can be done. Even in this case the eda tool need not know the details of model type or nature of its implementation. The whole idea of ami model is, it is a black box. Quoting fangyi_rao@xxxxxxxxxxx:Some customers want the eda tool to optimize these taps and set their values in the ami Init call. Fangyi -----Original Message----- From: ckumar@xxxxxxxxxxx [mailto:ckumar@xxxxxxxxxxx] Sent: Thursday, February 11, 2010 10:16 AM To: RAO,FANGYI (A-USA,ex1) Cc: ambrishv@xxxxxxxxxxx; ibis-macro@xxxxxxxxxxxxx Subject: Re: [ibis-macro] Re: question on tap parameters in AMI why should the eda tool know what type of filter or whatever it is? As far as the eda tool is concerned the only job it has to do is to pass the model instances of some arbitrarily named parameters whose values comply with ami definition. Quoting fangyi_rao@xxxxxxxxxxx:Hi, Ambrish; Thanks for the clarification. In your example a EDA tool will find two groups of tap parameter, RX_FFE_Taps and RX_DFE_Taps in the .ami file based on the parameter type. How does the tool know which group is for FFE and which is for DFE? Note that model specific parameter names can be arbitrary. Fangyi From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Ambrish Varma Sent: Wednesday, February 10, 2010 7:57 PM To: ibis-macro@xxxxxxxxxxxxx Subject: [ibis-macro] Re: question on tap parameters in AMI Hi Fangyi, You can give any name to the parameters themselves. For ex, The model_specific section of the RX model with a 5 tap FFE and 3 tap DFE can look like: (Model_Specific (RX_FFE_Taps (-2 (Usage Inout)(Type Tap) (Format Range 0.1 -0.1 0.2)(Default 0.1) (Description "Second Precursor Tap")) (-1 (Usage Inout)(Type Tap) (Format Range 0.2 -0.4 0.4)(Default 0.2) (Description "First Precursor Tap")) (0 (Usage Inout)(Type Tap) (Format Range 1 -1 2)(Default 1) (Description "Main Tap")) (1 (Usage Inout)(Type Tap) (Format Range 0.2 -0.4 0.4)(Default2 0.2) (Description "First Post cursor Tap")) (2 (Usage Inout)(Type Tap) (Format Range 0.1 -0.1 0.2)(Default 0.1) (Description "Second Post cursor Tap")) ) (RX_DFE_Taps (-1 (Usage Inout)(Type Tap) (Format Range 0.2 -0.4 0.4)(Default0.2)(Description "First Precursor Tap")) (0 (Usage Inout)(Type Tap) (Format Range 1 -1 2)(Default 1) (Description "Main Tap")) (1 (Usage Inout)(Type Tap) (Format Range 0.2 -0.4 0.4)(Default20.2)(Description "First Post cursor Tap")) ) ) | end model_specific Hope that helps, Ambrish. ________________________________ From: ibis-macro-bounce@xxxxxxxxxxxxx [mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of fangyi_rao@xxxxxxxxxxx Sent: Wednesday, February 10, 2010 9:21 PM To: ibis-macro@xxxxxxxxxxxxx Subject: [ibis-macro] question on tap parameters in AMI Hi, Experts; I have a question on tap parameter definition in .ami file. Thecurrentstandard states that: If in addition the individual tap weights are each given a name which is their tap number (i.e., "-1" is the name of the first precursor tap, "0" is the name of the main tap, "1" is the name of the first postcursor tap, etc.) and the tap weights are declared to be of type Tap, then the EDA platform can assume that the individual parameters are tap weights in a tapped delay line This way we have to assume that Tx only has FFE and Rx only has DFE. What if Rx has both FFE and DFE? How can we tell which group of tapsisFFE and which is for DFE? Thanks in advance. Fangyi--------------------------------------------------------------------- IBIS Macro website : http://www.eda.org/pub/ibis/macromodel_wip/ IBIS Macro reflector: //www.freelists.org/list/ibis-macro To unsubscribe send an email: To: ibis-macro-request@xxxxxxxxxxxxx Subject: unsubscribe
-- Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC