I have funny problem with ethernet shield. I am using version 21 software. Duemillanove and official ethernet shield with W5100.
My Arduino controls my remote station electric energy production and usage. And it sends data as statistics to pachube (www.pachube.com/feeds/7458
) and from webserver it checks if there are configuration changes, and adjusts its RTC time with NTP.
It is designed to work without internet. If ethernet is disconnected it is no problem. But now problem comes. If there are problems with internet further away from local router, that causes no response from webserver or other services, connection making hangs for too long before shield returns "no connection". This again causes Watchdog to reset the whole system, which again causes loss of power in the whole system. So every time lights go out I know there is no internet again
So, question is how to make timeout happen faster?
Of the working principle and saving power, ethernet shield is switched off if not used. Every time it is powered up, waited until it resets properly and then initialised for every usege. So there can not be multiple connection problem. And it hangs on connect();