>>>>> Anton Erasmus <nobody@spam.prevent.net> writes:
>>>>> On Tue, 22 Jan 2013 00:14:04 -0800 (PST), pozzugno@gmail.com wrote:
[...]
>> What is the smallest and cheapest solution? A microcontroller with
>> embedded MAC and an external PHY, magnetics and connector, or a
>> microcontroller with an external Ethernet controller (with MAC+PHY
>> integrated), magnetics and connector?
> You can use the Wiznet W7200 - ARM32bit Cortex M3 with hardwired
> TCP/IP, MAC & PHY.
I wonder if it is TCP/IPv4-only, or does it support TCP/IPv6,
too (i. e., "dual-stack")?
Is there a list of TCP/IPv6 implementations for embedded systems
somewhere on the Web, BTW?
> It takes about 10 lines of C code to setup enough that the device
> responds to ping requests.
--
FSF associate member #7257
Reply by Anton Erasmus●February 5, 20132013-02-05
On Tue, 22 Jan 2013 00:14:04 -0800 (PST), pozzugno@gmail.com wrote:
>I have to create a small network composed by some nodes. At the moment, the number of nodes is about 10, but I want to have a flexible architecture that could increase in the future.
>
>I think Ethernet is a very good bus technology that solves many problems to the developer: framing, multi-master, addressing, conflicts, ...
>
>I don't need the full TCP/IP stack that needs high resources. I just want to send raw Ethernet packets to the bus and receive raw packets from the bus (like for RS485).
>I don't need very high-speed, so it could be sufficient the 10Mbps. 100Mbps could be nice in the future.
>
>What is the smallest and cheapest solution? A microcontroller with embedded MAC and an external PHY, magnetics and connector, or a microcontroller with an external Ethernet controller (with MAC+PHY integrated), magnetics and connector?
You can use the Wiznet W7200 - ARM32bit Cortex M3 with hardwired
TCP/IP, MAC & PHY.
It takes about 10 lines of C code to setup enough that the device
responds to ping requests.
Regards
Anton Erasmus
Reply by Grant Edwards●January 26, 20132013-01-26
On 2013-01-26, Paul <paul@pcserviceselectronics.co.uk> wrote:
> In article <5cd5g8l9bib39vf9snsfagunqqmipkdr5e@4ax.com>,
> usenet@rwaltman.com says...
>>
>> Paul wrote:
>> >...
>> >Recent case, could not uninstall a wifi driver, as the app insisted on
>> >reinstalling driver even if the device suppossedly had no power. Normal
>> >mode start system driver crash, safe mode unable to uninstall or
>> >disable! That took some doing to disable.
>>
>> In some extreme cases like that, I was forced to boot from a Linux CD,
>> mount the windows disk and erase the offending files, (at least the
>> ones I could identify.)
>> Then reboot while crossing fingers ...
>
> Most Windows 'diagnostics' assume 95% of system is working first :-)
And they're useless for the other 5%.
--
Grant Edwards grant.b.edwards Yow! I have a VISION! It's
at a RANCID double-FISHWICH on
gmail.com an ENRICHED BUN!!
Reply by Paul●January 26, 20132013-01-26
In article <5cd5g8l9bib39vf9snsfagunqqmipkdr5e@4ax.com>,
usenet@rwaltman.com says...
>
> Paul wrote:
> >...
> >Recent case, could not uninstall a wifi driver, as the app insisted on
> >reinstalling driver even if the device suppossedly had no power. Normal
> >mode start system driver crash, safe mode unable to uninstall or
> >disable! That took some doing to disable.
>
> In some extreme cases like that, I was forced to boot from a Linux CD,
> mount the windows disk and erase the offending files, (at least the
> ones I could identify.)
> Then reboot while crossing fingers ...
Reply by Roberto Waltman●January 25, 20132013-01-25
Paul wrote:
>...
>Recent case, could not uninstall a wifi driver, as the app insisted on
>reinstalling driver even if the device suppossedly had no power. Normal
>mode start system driver crash, safe mode unable to uninstall or
>disable! That took some doing to disable.
In some extreme cases like that, I was forced to boot from a Linux CD,
mount the windows disk and erase the offending files, (at least the
ones I could identify.)
Then reboot while crossing fingers ...
--
Roberto Waltman
[ Please reply to the group,
return address is invalid ]
Reply by Paul●January 25, 20132013-01-25
In article <kds1t3$sbl$2@reader1.panix.com>, invalid@invalid.invalid
says...
>
> On 2013-01-24, Paul <paul@pcserviceselectronics.co.uk> wrote:
> > In article <kdptc0$4ss$1@reader1.panix.com>, invalid@invalid.invalid
> > says...
> >>
> >> On 2013-01-23, David Brown <david.brown@removethis.hesbynett.no> wrote:
> > .....
> >> > With Windows, life is more complicated - but it is still possible.
> >>
> >> From what I've gathered it's rather painful and is difficult to make
> >> work across different windows versions.
> >
> > What isn't difficult across Windows versions
>
> Touch�
But very true....
Dont even get me started on apps written in fixed pixels that are a pain
on different screen sizes. Worst you have problem come up in 'safe' mode
you cannot alter the settings as the dialog box is larger than screen.
That is of course if the settings can be modified without full
application running, which wont in safe mode.
Recent case, could not uninstall a wifi driver, as the app insisted on
reinstalling driver even if the device suppossedly had no power. Normal
mode start system driver crash, safe mode unable to uninstall or
disable! That took some doing to disable.
--
Paul Carpenter | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/> PC Services
<http://www.pcserviceselectronics.co.uk/fonts/> Timing Diagram Font
<http://www.gnuh8.org.uk/> GNU H8 - compiler & Renesas H8/H8S/H8 Tiny
<http://www.badweb.org.uk/> For those web sites you hate
Reply by Stef●January 24, 20132013-01-24
In comp.arch.embedded,
Grant Edwards <invalid@invalid.invalid> wrote:
> On 2013-01-24, David Brown <david@westcontrol.removethisbit.com> wrote:
>
>>> The 10base2 thinnet solution using 50 Ohm coax
>>> and BNC "T" connectors would be cute, but good luck getting parts.
>>> Can you even buy PHY chips and magnetics for 10base2 these days?
>>
>> I don't think coax Ethernet used magnetics - it certainly did not
>> have good isolation. I remember getting buzzed when connecting coax
>> Ethernet cables to computers on different mains circuits.
>
> That's interesting -- I assumed there was galvanic isolation. But now
> that I think about it, the BNC shell always appeared to be connected
> directly to chassis ground.
No, there was always a plastic part between case and metal shell of the
BNC. See this example: http://uk.shopping.com/Longshine-LCS-8034TB/info
A PCI 10base-T/10base2 combocard, still available.
--
Stef (remove caps, dashes and .invalid from e-mail address to reply by mail)
meetings, n.:
A place where minutes are kept and hours are lost.
Reply by Grant Edwards●January 24, 20132013-01-24
On 2013-01-24, Paul <paul@pcserviceselectronics.co.uk> wrote:
> In article <kdptc0$4ss$1@reader1.panix.com>, invalid@invalid.invalid
> says...
>>
>> On 2013-01-23, David Brown <david.brown@removethis.hesbynett.no> wrote:
> .....
>> > With Windows, life is more complicated - but it is still possible.
>>
>> From what I've gathered it's rather painful and is difficult to make
>> work across different windows versions.
>
> What isn't difficult across Windows versions
Touch�
--
Grant Edwards grant.b.edwards Yow! How's the wife?
at Is she at home enjoying
gmail.com capitalism?
Reply by Grant Edwards●January 24, 20132013-01-24
On 2013-01-24, David Brown <david@westcontrol.removethisbit.com> wrote:
> I didn't think about that - I've only used such programs during testing,
> and it's not a big problem to use root on a development machine. But I
> agree that using root for something you run often is not nice - even
> with setuid or CAP_NET_RAW (if I've got that one right).
I was wondering if SELinux had a capability that could fix that
problem, but I don't have SELinux installed on any of my boxes, and
requiring it of customers wouldn't be an option.
>>> You can happily use languages like Python for this to do it quickly
>>> and simply.
>>
>> I know. I was the one who added raw socket support to Python because I
>> had to deal with the headache of troubleshooting stuff that uses raw
>> Ethernet. :)
>
> Well, I owe you my thanks here. It made some development work I did
> much easier.
>
> I haven't used raw Ethernet much in practice - I only used it as a
> stepping stone to getting LWIP working on an MPC microcontroller.
> But it was easy to set up, and easy to work with on the PC (using
> Python, as root...), and let me troubleshoot my MAC setup.
Using raw ethernet as a development step makes a lot of sense.
Supporting it in a product is where all the headaches start.
> Basically, I think that if you are communicating over Ethernet with a
> PC (Windows, Linux, whatever) or other standard equipment, then IP
> with UDP and/or TCP is definitely the right choice. But raw Ethernet
> is quite a realistic option for a closed network between nodes that
> you have full control over, and the low and predictable latencies can
> fit far better in many industrial applications than UDP.
If you can keep the network closed and really don't want to talk to
PCs, then it may be a good option.
>> The 10base2 thinnet solution using 50 Ohm coax
>> and BNC "T" connectors would be cute, but good luck getting parts.
>> Can you even buy PHY chips and magnetics for 10base2 these days?
>
> I don't think coax Ethernet used magnetics - it certainly did not
> have good isolation. I remember getting buzzed when connecting coax
> Ethernet cables to computers on different mains circuits.
That's interesting -- I assumed there was galvanic isolation. But now
that I think about it, the BNC shell always appeared to be connected
directly to chassis ground.
--
Grant Edwards grant.b.edwards Yow! I once decorated my
at apartment entirely in ten
gmail.com foot salad forks!!
Reply by Grant Edwards●January 24, 20132013-01-24
On 2013-01-23, David Brown <david.brown@removethis.hesbynett.no> wrote:
> If you want to write PC code to communicate with your system, it's easy
> with Linux - just open a raw socket and away you go. You can happily
> use languages like Python for this to do it quickly and simply. With
> Windows, life is more complicated - but it is still possible.
An intesting coincidence...
In my department staff meeting this morning, the engineer who is
responsible for one of the Windows apps that talks raw ethernet to one
of our product lines says the app doesn't work under the latest
versions of Windows 8 (it did work with earlier versions of Win8). I'm
sure we'll get it to work again, but everybody involved will agree
that over the life of the product, choosing raw ethernet created
orders of magnitude more work work than it saved.
Choosing raw ethernet many years ago probably saved _one_ firmware
engineer a few weeks effort. In the years since, it has probably cost
several man years of extra work.
According to the tech support support guys, raw ethernet is a constant
source of breakage for people with any sort of third-party windows
"security" software installed.
> Raw Ethernet is faster, more predictable and has lower overheads than
> IP - even UDP. That is why it is used for protocols like ATA over
> Ethernet.
For ATAoE or SCSIoE, that small overhead is important. For turning
the lamp in the living room on/off, it's not.
--
Grant Edwards grant.b.edwards Yow! And then we could sit
at on the hoods of cars at
gmail.com stop lights!