Re: Optional PMA interface (OIF)
Henning,
Sorry about the confusion. I did mention in my note that there would have to be
two optional clock references specified in the XBI, one for the LAN PHY and the
other for the WAN PHY.
What I should have said is that only one clock MULTIPLE be specified. For
example, 161.1328125 MHz is 1/4 of 644.53125 MHz and 155.52 MHz is 1/4 of 622.08
MHz. One fourth is a good multiple to use. This means that other multiples
should not be required anywhere in the standard, even optionally (i.e. 1/8, 1/2,
1/16, 1/1, etc.)
Best Regards,
Rich
--
"Lysdal, Henning" wrote:
>
> Rich,
>
> I don't see how you can avoid having separate reference clocks for LAN and
> WAN (with realistic PLL design).
>
> In the LAN case there are several options
> 156.25 MHz (seems to be prefered among serial folks)
> 161.1328125 MHz
> 644.53125 MHz
>
> In the WAN case the OIF specifies 622.08 MHz. I know of a lot of people who
> also like 155.52 MHz
>
> Now the problem is: how do you synthesize 9.95328 GHz and 10.3125 GHz from
> the same reference. If you use a 10 kHz reference, it's easy, but you will
> most likely have problems with transmit jitter.
>
> So I haven't been discussing the WAN case at all, since I was under the
> impression that WAN PHYs will use existing SONET SerDes using 622.08 MHz
> refck.
>
> Regards,
>
> Henning
>
> -----Original Message-----
> From: Rich Taborek [mailto:rtaborek@xxxxxxxxxxxxx]
> Sent: 15. juni 2000 07:25
> To: HSSG
> Subject: Re: Optional PMA interface (OIF)
>
> Henning, et. al.
>
> This proposal sounds OK on the surface. I have one concern:
>
> If the XBI RefCLK is optional, and if the option is implemented, only one
> CLK frequency should be specified in order to foster interoperability.
> This appears to be the intention of the proposal. Note also that means
> one CLK frequency for the LAN PHY and another for the WAN PHY.
>
> Best Regards,
> Rich
>
> --
>
> Henning Lysdal wrote:
> >
> > Tom,
> >
> > Oops sorry for this delayed response. I can support your proposal.
> >
> > Are you working with Stuart to get this into his presentation?
> >
> > Regards,
> >
> > Henning
> > > -----------------------------------------
> > > Henning Lysdal
> > > Design Engineer
> > > GiGA A/S - an Intel Company
> > > Mileparken 22
> > > DK-2740 Skovlunde
> > > Denmark
> > > Tel.: +45 70 10 10 62, Fax: +45 70 10 10 63
> > > Direct: +45 44 54 61 54
> > > E-mail: hl@xxxxxxx
> > > Web: www.giga.dk, www.intel.com
-------------------------------------------------------
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