[En-Nut-Discussion] Your project pls. keep me posted

Fri Sep 3 04:46:54 CEST 2004

Hello:

This seems to me real acid test for the Ethernet boards! Please keep me
posted and copy me on the development.
I am still on my learning curve as well with Ethernut.

Thanks,

Berns

----- Original Message ----- 
From: <en-nut-discussion-request at egnite.de>
To: <en-nut-discussion at egnite.de>
Sent: Wednesday, September 01, 2004 2:00 AM
Subject: En-Nut-Discussion Digest, Vol 11, Issue 1

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> Today's Topics:
>
>    1. Large number of simultaneous network connections with the
>       Ethernut OS. (Louis B)
>    2. Re: Large number of simultaneous network connections with the
>       Ethernut OS. (Harald Kipp)
>    3. Bugs ? or Function cancel on new 3.4.3 ? (iVesWorking)
>    4. Re: Bugs ? or Function cancel on new 3.4.3  ? (Harald Kipp)
>    5. new version of WinAVR Compatible problem (iVesWorking)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 31 Aug 2004 12:24:11 +0000
> From: "Louis B" <louisjbarman at hotmail.com>
> Subject: [En-Nut-Discussion] Large number of simultaneous network
> connections with the Ethernut OS.
> To: en-nut-discussion at egnite.de
> Message-ID: <BAY15-F34HLafPH6enH0003de44 at hotmail.com>
> Content-Type: text/plain; format=flowed
>
> Hello,
>
> I have selected the Ethernut for a new project and I require your help
with
> the design of the software. I am totally new to the Ethernut API and I am
> not sure which approach to take when writing the software.
>
> First I need to fill you in with some details of this project. There is an
> existing project, for which I wrote all the code, that runs on an embedded
> board that has 16 UARTs. To simplify it slightly 15 of these UARTs are
used
> as a giant cross point  switch, so that messages received by one of these
> UARTs may be passed through to one or more of the other UARTs. (In reality
> there are also polling engines within the software that is collecting
> information and sending commands to the devices connected to the UARTs).
Two
> of these boards have been cross linked together using the 16th UARTs to
> produce a giant 30 channel system.
>
> We now wish to expand the system into a 64 channel system (with 64 UARTs
in
> total) and it is for this project that I have selected the Ethernut
boards.
> We have designed a board with eight UARTs that plugs into the Ethernut
> board. (These UARTs have 64 byte hardware buffers and so we do not need to
> worry about interrupts). Eight of these boards will be used with 8
Ethernut
> boards all linked together by a network to produce a giant 64 channel
> system. It is how to port the original software onto the Ethernut system
for
> which I need your help. The original software does not use tasks, but
> instead uses a round robin control loop.
>
> Now for the questions.
>
> 1. Is it possible for the Ethernut board to send messages simultaneously
to
> seven other boards. (there is a low data rate with short fixed length
> message so bandwidth should not be a problem). Is there a limit to the
> number of simultaneous connections that can be handled by the Ethernut
> board?
>
> 2. Which protocol do you recommend that I used to send messages between
the
> eight Ethernut boards; TCP/IP or UDP? (Please bear in mind that each
> Ethernut may be required to send messages simultaneously to seven others.
I
> am using short fixed length packets of 16 bytes).
>
> 3. What is the best way of integrating the Ethernut threads with the round
> robin approach I have taken with the original software? Currently I am
> thinking that there will need to be a separate thread for each of the 7
> network connections. These messages would need to be queued up so that
they
> could be handled by the idle task which would contain the round robin
> control loop.
>
> 4. As an alternative, is it possible not to use threads with the Ethernut
> OS, but instead use a polling method for talking to the network
connections.
> For example having a system call that determines if there are any packets
> available from the network that need to be read. This would allow the
round
> robin control loop to continue without being halted.
>
> 5. Are network connections bi-directional? Would seven network connections
> and seven tasks be needed to set up seven bi-directional links with the
> other Ethernut boards? Or would 14 network connections and 14 tasks be
> needed to set up single directional links?
>
>
> I would be most grateful if you could point me in the right direction for
> this project. It would be most useful if you could provide me with the
bare
> bones out line of how I should start coding this project. Finally what is
> the most relevant sample code that I should look at when starting this
> project.
>
> Thanks in advance for your help.
>
> (if you are interested the website for this my company website is
> http://www.radamecbroadcast.co.uk)
>
> Louis B.
>
> _________________________________________________________________
> It's fast, it's easy and it's free. Get MSN Messenger today!
> http://www.msn.co.uk/messenger
>
>
>
> ------------------------------
>
> Message: 2
> Date: Wed, 01 Sep 2004 10:53:36 +0200
> From: Harald Kipp <harald.kipp at egnite.de>
> Subject: Re: [En-Nut-Discussion] Large number of simultaneous network
> connections with the Ethernut OS.
> To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
> Cc: Louis B <louisjbarman at hotmail.com>
> Message-ID: <5.1.1.6.0.20040901101005.01c28ff0 at egnite.de>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> Hello Louis,
>
> you need to subscribe to the list at
> http://www.egnite.de/mailman/listinfo.cgi/en-nut-discussion
> to get posts through without moderator confirmation.
>
> At 12:24 31.08.2004 +0000, Louis B wrote:
>
> >1. Is it possible for the Ethernut board to send messages simultaneously
> >to seven other boards. (there is a low data rate with short fixed length
> >message so bandwidth should not be a problem). Is there a limit to the
> >number of simultaneous connections that can be handled by the Ethernut
board?
>
> This is limited only by available memory. Not sure how
> much RAM a single connection consumes exactly, but not
> more than a few hundred bytes. Seven concurrent connections
> should be no problem.
>
>
> >2. Which protocol do you recommend that I used to send messages between
> >the eight Ethernut boards; TCP/IP or UDP? (Please bear in mind that each
> >Ethernut may be required to send messages simultaneously to seven others.
> >I am using short fixed length packets of 16 bytes).
>
> If the same message has to be sent to all nodes, then
> UDP will significantly reduce the overhead, because
> messages can be broadcasted. TCP doesn't support broadcasts.
>
> Note that UDP is considered unreliable, so you need to
> add some kind of ACK handshaking.
>
> TCP is reliable and, as a result, complicated under the hood.
> If data loss is no problem and maximum transfer speed doesn't
> matter, UDP is the first choice anyway.
>
>
> >3. What is the best way of integrating the Ethernut threads with the
round
> >robin approach I have taken with the original software? Currently I am
> >thinking that there will need to be a separate thread for each of the 7
> >network connections. These messages would need to be queued up so that
> >they could be handled by the idle task which would contain the round
robin
> >control loop.
>
> Yes, I'd suggest to create seven network receiver threads.
> With Nut/OS it is possible to receive data in one thread
> and transmit data on another using the same socket.
>
>
> >4. As an alternative, is it possible not to use threads with the Ethernut
> >OS, but instead use a polling method for talking to the network
> >connections. For example having a system call that determines if there
are
> >any packets available from the network that need to be read. This would
> >allow the round robin control loop to continue without being halted.
>
> Yes, this is possible but consumes more CPU time than
> the threaded model and may also consume more code space.
> I assume, that Ethernut will be far from its limits for
> this application, so you can use round robin, it this
> makes porting easier.
>
> In the first place keep an eye on data memory consumptions
> (RAM). Typically this is the limit for most applications.
>
>
>
> >5. Are network connections bi-directional? Would seven network
connections
> >and seven tasks be needed to set up seven bi-directional links with the
> >other Ethernut boards? Or would 14 network connections and 14 tasks be
> >needed to set up single directional links?
>
> TCP as well as UDP are, of course, bi-directional, although
> many UDP applications use a server socket on both sides.
>
>
>
>
> >I would be most grateful if you could point me in the right direction for
> >this project. It would be most useful if you could provide me with the
> >bare bones out line of how I should start coding this project. Finally
> >what is the most relevant sample code that I should look at when starting
> >this project.
>
> Actually this is a simple application, but I know, that
> "the devil hides in the details" as we say in Germany. :-)
>
> One good example is
>
http://cvs.sourceforge.net/viewcvs.py/*checkout*/ethernut/nut/app/rs232d/rs232d.c?rev=1.2
> That's already a bit too complicated, because it uses
> continues streams and the StreamCopy() routine is used
> for both transports, RS232 to LAN and LAN to RS232.
>
> One good thing with Nut/OS is, that it is very similar
> to PC programming. You may consider to try your application
> outline on Linux or Windows first and later port it to
> Nut/OS.
>
> It is even possible to emulate Nut/OS on Linux (contributed
> by Matthias Ringwald and available in CVS). A Win32 emulator
> for Nut/OS is commercially available from
> http://technology4gis.com/
>
> But, as I said, your application doesn't look that difficult.
> As usual, the main problem may be to get a feeling for the
> capabilities, so best look to the examples and try to follow
> them.
>
>
>
> >Thanks in advance for your help.
>
> You're welcome.
>
>
>
>
> >(if you are interested the website for this my company website is
> >http://www.radamecbroadcast.co.uk)
>
>
> Really cool stuff.
>
> Harald
>
>
>
> ------------------------------
>
> Message: 3
> Date: Wed, 1 Sep 2004 10:08:23 +0100
> From: "iVesWorking" <ivesworking at hotmail.com>
> Subject: [En-Nut-Discussion] Bugs ? or Function cancel on new 3.4.3 ?
> To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
> Message-ID: <BAY1-DAV2zGzeZatQrq0002fad6 at hotmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> i have
> warning: assignment discards qualifiers from pointer target type
> on the code i been write,
> i think i using 342 to write my code, after migrate to 343 i have nearly
hundred of the same warning,
>
> this warning is something like
> prog_char *st_P;
> static prog_char st_unknown[] = "UNKNOWN";
> st_P = st_unknown;    <- the warning line
>
> any idea how to fix this problem ?
>
>
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> ------------------------------
>
> Message: 4
> Date: Wed, 01 Sep 2004 11:27:18 +0200
> From: Harald Kipp <harald.kipp at egnite.de>
> Subject: Re: [En-Nut-Discussion] Bugs ? or Function cancel on new
> 3.4.3  ?
> To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
> Message-ID: <5.1.1.6.0.20040901112626.01c2a130 at egnite.de>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> Does UserConf.mk contain
>
> HWDEF=-D__HARVARD_ARCH__ -DETHERNUT2
>
> for Ethernut 2 or
>
> HWDEF=-D__HARVARD_ARCH__
>
> for Ethernut 1?
>
> Harald
>
> At 10:08 01.09.2004 +0100, you wrote:
> >i have
> >warning: assignment discards qualifiers from pointer target type
> >on the code i been write,
> >i think i using 342 to write my code, after migrate to 343 i have nearly
> >hundred of the same warning,
> >
> >this warning is something like
> >prog_char *st_P;
> >static prog_char st_unknown[] = "UNKNOWN";
> >st_P = st_unknown;    <- the warning line
> >
> >any idea how to fix this problem ?
> >
> >
> >
> >_______________________________________________
> >En-Nut-Discussion mailing list
> >En-Nut-Discussion at egnite.de
> >http://www.egnite.de/mailman/listinfo.cgi/en-nut-discussion
>
>
>
> ------------------------------
>
> Message: 5
> Date: Wed, 1 Sep 2004 10:47:26 +0100
> From: "iVesWorking" <ivesworking at hotmail.com>
> Subject: [En-Nut-Discussion] new version of WinAVR Compatible problem
> To: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
> Message-ID: <BAY1-DAV3kq63oWvfHC0002c582 at hotmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> it seem we have compatible problem on the new version of WinAVR, Anyone
know what happenning ?
> I found that some pointer that heavily use on Ethernut example stop
working.
> specially the example httpd.
>
> Anyone Know what happening?
>
> I been force to install the old 20040404 version.
> the version i had problem with was WinAVR-20040720
>
> WF
>
>
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