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.
Bob On Dec 28, 2012, at 10:21 AM, Jim Lux <jim...@earthlink.net> wrote: > On 12/27/12 11:48 AM, Attila Kinali wrote: >> On Thu, 27 Dec 2012 11:30:37 -0800 >> Jim Lux <jim...@earthlink.net> wrote: >> >>> So, what about the USB-Ethernet dongles? (I use them a lot at work to >>> add a second interface for a laptop in test equipment setups, talking to >>> a Prologix, for instance) >> >> A lot worse! One thing is that USB has a polled protocol (ie the host >> has to ask whether the device has any data) and the slot when an USB >> device can signal that a packet came in repeates it self at most a couple >> of times per 1ms frame for FS (don't know from the top of my head for HS). >> The bigger issue though is that drivers for ethernet dongles are usally >> of quite bad quality (ie it takes them a long time to do anything), and >> they try to queue as much as possible to increase troughput (which adds >> unpredictable delay). >> > > OK, so throw out the USB version.. > > Just thinking out loud here: are these $20 wonders potentially a way to get > "better" time transfer via Ethernet? > > I can see that a PC interface version might not be very good (because of the > need to build a low jitter driver for the PC for SPI or RS232). > > But what about connected to some purpose built widget.. That is, rather than > invest in a IEEE 1588 interface, could one cobble together something that > does somewhere in between the vanilla mobo Ethernet & network driver that > came with the OS on the "high jitter" end and some IEEE 1588 rev2 on the "low > jitter" end. > > > > After all, there's no real "driver" when you're hooking it up to an Arduino. > > There might be some significant uncertainty in the microcontroller inside the > interface chip: it does quite a lot. But maybe not.. I haven't looked at it, > and I was just curious. > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.