Re: [Linuxptp-users] List of Boundary clocks

[Mozhdeh K. <kam...@gm...>]

I could not find time stamping accuracy of Freescale P2020, do you know the
exact accuracy of it?

BR,
Mozhdeh


On Thu, Mar 21, 2013 at 7:58 PM, Richard Cochran
<ric...@gm...>wrote:

> On Thu, Mar 21, 2013 at 01:28:04PM +0100, Mozhdeh Kamel wrote:
> >
> > Can anyone help me with the list of boundary clocks?I wonder whether
> > boundary clocks are simple switch with hardware time stamping? what
> special
> > characteristics it must have?
>
> A boundary clock (BC) is more like a router than a switch. It must
> intercept incoming PTP messages, and it does not forward them (except
> for management messages).
>
> Although linuxptp is designed to work as a BC, I don't know of any
> that are using linuxptp. If you want to try the code out, then you
> need a computer with two or more ports, all of which share a common
> PTP Hardware Clock (PHC). I can think of two ways to do this.
>
> 1. Use a computer whose ports all support SW time stamping. This will
>    not perform very well, but at least you can see how it works.
>
> 2. Get a computer with true HW time stamping support. Note that you
>    cannot just use a box with multiple PCI cards, for example. The
>    ports must all share *one* clock.
>
>    Some ready made system on chips have this, like the Freescale P2020,
>    the MPC8306, and the MPC8309. If you have one of these kits, then
>    the ptp4l program should work fine.
>
>    Another possibility is to use the DP83640 PHY, but you must make
>    sure to connect the GPIOs in your design so that the PHYs can
>    synchronize each other.
>
> HTH,
> Richard
>



-- 
*Mozhdeh *