[ibis-macro] Re: Structural changes to the AMI standard required to support Backchannle Co-optimization
- From: ckumar <ckumar@xxxxxxxxxxx>
- To: <wkatz@xxxxxxxxxx>
- Date: Fri, 11 Feb 2011 10:41:19 -0800
I see that this proposal exposes the entire architecture of tx and rx to
each other and expects them to interpret each other's parameters.
The back channel communication standards are based on minimalist and
necessary communication between rx and tx.
from rx:
1. rx knows the number of taps in tx
2. rx can only ask tx to increment/decrement the taps. It does not or care
to know what the absolute value of tx means
from tx:
tx communicates to rx whether the the specified taps are adjustable at all
or they have reached their min/max limit
The mode of communication also depends upon the standard and should be
defined in the particular standards file
On Fri, 11 Feb 2011 09:00:05 -0500, "Walter Katz" <wkatz@xxxxxxxxxx>
wrote:
> IBIS-ATM,
>
>
>
> This e-mail is being sent to the IBIS ATM (Advanced Technology Modeling)
> group to describe the structural changes required to the IBIS-AMI
> interface.
> The Backchannel Reflector is being cc's as well.
>
>
>
> Two changes are required to the IBIS-AMI interface to support
backchannel.
> The first is to allow the Tx AMI DLL to know what the Rx AMI DLL is
telling
> it and the Rx AMI DLL needs to know what the Tx AMI DLL is telling it.
> Information is currently passed into a DLL as a text string in in a
similar
> parameter tree format as defined in the .ami file for that model. The
roor
> of this parameter tree is the root of the parameter tree in the .ami
file.
> The simple enhancement to the AMI interface is to allow this string to
> contain two parameter trees, one with the root of the parameter tree for
> the
> model, and the other tree containing the root of the parameter tree fo
the
> model at the other end of the channel. The following example should make
> this clearer:
>
>
>
> Assume that the parameter tree for the Tx model is:
>
>
>
> (Tx_Root (FFE_Tap (-1 -.03) (0 .9) (1 -.07)))
>
>
>
> and the parameter tree for the Rx model is:
>
>
>
> (Rx_Root (DFE_Tap (1 -.1) (2 -.05) (3 .05) (4 .1) (5 -.01)))
>
>
>
> In the current standard the Tx just gets the (Tx_Root .) tree and the Rx
> just gets the (Rx_Root .) tree.
>
>
>
> The proposed change will allow the Tx model to receive:
>
>
>
> (Tx_Root (FFE_Tap (-1 -.03) (0 .9) (1 -.07))) (Rx_Root (DFE_Tap (1 -.1)
(2
> -.05) (3 .05) (4 .1) (5 -.01)))
>
>
>
> and the Rx model to receive
>
>
>
> (Rx_Root (DFE_Tap (1 -.1) (2 -.05) (3 .05) (4 .1) (5 -.01))) (Tx_Root
> (FFE_Tap (-1 -.03) (0 .9) (1 -.07)))
>
>
>
>
>
> Thus, the Rx model can determine the number of Tx pre-cursor and
> post-cursor
> taps, and the values of all of the Tx taps.
>
>
>
>
>
> The DLL's not only receive data in this format, but also output data in
> this
> same format. Thus the Rx model can output these same trees with updated
> values of the Tx Taps.
>
>
>
>
>
> As described in previous e-mails, there are three entry points to an AMI
> model, AMI_Init, AMI_GetWave, and AMI_Close. The AMI_Init entry has a
> parameters_in pointer and a parameters_out pointer. The AMI_GetWave
entry
> only has a parameters_out pointer. Since Backchannel will require the
> ability to pass a parameter tree inot the AMI_GetWave entry, the AMI
> interface standard needs to modified to allow the AMI_GetWave
> parameters_out
> pointer to also serve as a pointer to an input string.
>
>
>
> To enable the above changes, we will need to define a new Reserved
> Parameter
> to indicate that this DLL does support multiple parameter trees in the
> input
> parameter tree, and that the AMI_GetWave support the parameter_out
pointer
> use as an input as well as an output.
>
>
>
> Walter
>
>
>
>
>
> Walter Katz
>
> Chief Scientist
>
> Signal Integrity Software, Inc.
>
> wkatz@xxxxxxxxxx
>
> 303.449-2308
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