[En-Nut-Discussion] Opened TCP connection. Watchdog timers going ok here. Realtek stopping for a breather.

Alexander Baranov Baranov at intech21.com
Tue Jun 1 15:15:55 CEST 2004

I use Ethernet-2. Actually, the system does not hang forever and works due
to the watchdog. I program it exactly as you advised.
I passed the problem by periodical closing and opening the socket. But I try
to implement Modbus via TCP protocol and it recommends to keep the socket
open. Well, I still admit that the problem is in my head...
Regards, Alex.
----- Original Message -----
From: "Brett Abbott" <Brett.Abbott at digital-telemetry.com>
To: <en-nut-discussion at egnite.de>
Sent: Sunday, May 30, 2004 4:45 PM
Subject: [En-Nut-Discussion] Opened TCP connection. Watchdog timers going ok
here. Realtek stopping for a breather.

> Hi
> We have observed and measured noticable periods of "hang" when the
ethernet port is enabled, configured and idle with a listener running.
> We had a unit which needed to communicate in a tight rs232 handshake with
a connected device and we were getting timeouts.   With a serial analyser,
we detected delays were >50ms and less than 300ms, during which the
interupts appear not to run.  Whilst following the "turn everything off bit
by bit till it goes" mantra, I found that the problem went away when the
ethernet adaptor wasnt initialised at all.  If the adaptor was initialised,
it was intermittent, although more frequent when not being watched (via
ethernet).  This later observation could be similar to what you were seeing
as I hadnt the time to see if my monitoring TCP connection impacted the
results - I certainly didnt assume that heavier traffic would improve the
> Im using Ethernut 1, ref F.  Nutos 330, but are planning to upgrade at the
next release.
> We have the Watchdog up and running but had to allow for the realtek
Ethernet adaptor when making it go.  A few tips:
>    1. We had to set the watch dog timeout at 2secs.  anything less meant
that (a) initialising the ethernet adaptor would cause reboot. (b) idle
states (above issue) could trigger reboot.
>    2. Care to be taken when initialising the adaptor.  If you write big
unweildy code like me, you will need to place a "WDR" before and after the
call to initialise the adaptor.
>    3. Place your code to initialise the Watchdog and establish a 2 second
tick in the nutinit code otherwise you may not have enough time to enter the
"main" section before the big R.
> How did I fix the 1st problem?  Didnt need the ethernet adaptor except for
debugging.  Turned it off.  PPP works fine.
> I'd be very interested in how others have implemented the Watchdog, if at
all, please let me know off list and if there is interest, I could publish a
combined paper for Harald and Oliver.
> If the "ethernet hang/pause" is a known issue, I'd also appreciate any
guidance or pointers.
> Regards
> Brett
> ------------------------------
> Message: 4
> Date: Thu, 27 May 2004 16:00:47 -0400
> From: "Alexander Baranov" <Baranov at intech21.com>
> Subject: [En-Nut-Discussion] opened TCP connection
> To: <en-nut-discussion at egnite.de>
> Message-ID: <001501c44425$4e2edfb0$1101000a at Alex>
> Content-Type: text/plain; charset="koi8-r"
> Hi.
> I have to establish TCP connection and stay connected for a long time
> several hours).  I create a socket 'dirsock' , start accepting the
> connection with port 23 (telnet)  - NutTcpAccept(dirsock, 23). When
> connected, I go to an infinite looped command monitor. It works fine but
> I stop active data exchange (issuing monitor commands through telnet) it
> hangs after 10-15 seconds of idle state  and reboots through watchdog
> Is it natural behavior of connected sockets without active data transfer
> I miss something as usual?
> Thanks,
> Alexander Baranov
> Intech21, Inc.
> 50 Glen Street,
> Glen Cove, NY, 11542
> www.intech21.com
> --------------
> -----------------------------------------------------------------
> Brett Abbott, Managing Director, Digital Telemetry Limited
> Email: Brett.Abbott at digital-telemetry.com
> PO Box 24 036 Manners Street, Wellington, New Zealand
> Phone +64 (4) 5666-860  Mobile +64 (21) 656-144
> ------------------- Commercial in confidence --------------------
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