[time-nuts] clock-block any need ?

Azelio Boriani azelio.boriani at screen.it
Fri Dec 28 21:04:32 UTC 2012


STMicroelectronics has a 37 pages paper

http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/APPLICATION_NOTE/DM00030825.pdf

on the ethernet hardware time stamping MAC of the STM32M107. The National
DP83640 hardware time stamping PHY is another example (and was already
pointed out here some time ago).


On Fri, Dec 28, 2012 at 9:54 PM, <shalimr9 at gmail.com> wrote:

> I have used a commercial stack for 8 bit microcontrollers (Micronet CMX)
> and as is, it would be a bad choice for timing because of the time it
> spends processing  packets before deciding if they are for itself or not.
> It could be modified but you need a developer license to get the source
> code, and it starts at $15,000. I believe.
>
> Didier
>
> Sent from my Droid Razr 4G LTE wireless tracker.
>
>
>
> -----Original Message-----
> From: Bob Camp <lists at rtty.us>
> To: Discussion of precise time and frequency measurement <
> time-nuts at febo.com>
> Sent: Fri, 28 Dec 2012 11:36 AM
> Subject: Re: [time-nuts] clock-block any need ?
>
> Hi
>
> It's still an encapsulated stack that just coughs up the information after
> it's done this and that to it. How long the this and that takes is
> dependent on how busy the network is. It's going to watch packets on the
> net first and push data to the Arduino second.
>
> I'm beating on a similar part between posts. It *really* lags out as the
> traffic goes from near nothing to just a bit more than nothing. I'm not far
> enough into it to be able to put numbers on either measure. Looks like the
> units are in the thousands of bits per second range though.
>
> Bob
>
> On Dec 28, 2012, at 11:18 AM, Jim Lux <jimlux at earthlink.net> wrote:
>
> > On 12/28/12 7:56 AM, Bob Camp wrote:
> >> Hi
> >>
> >> Everything I've seen on the Adruino are "single chip wonders". They
> encapsulate the entire TCP/IP stack on the external chip. That will make
> getting at anything pretty tough.
> >>
> >
> >
> > Well, they also do UDP..(at least the Wiznet 5100 does)..
> > I was wondering if the timing from "UDP datagram received" to "some
> signal that Arduino sees" was deterministic at a useful level...
> >
> > The Arduino code I've looked at seems to be at a "sockets" kind of
> interface and there is an interrupt from the hardware when something
> arrives.
> >
> >
> >
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