I finally fixed this problem. I was using a pcb after it was freed (the error callback freed the pcb) and I also had some synchronity problems.
What I don´t get is, why does the LWIP code not check if the pcb us already freed? Does it assume it only gets right and working pcbs?
> I would start by checking that the ethernet driver works, the port
> works, take a known to work application and make sure that everything
> If errors arise here, it is quite possible that either the driver is
> buggy or the port is buggy. All calls to low-level functions must be in
> the same thread.
> Once that is checked and confirmed functional, I would continue by
> providing information on what API I am using on my application, and at
> what point something fails, after trying to collect more information
> with a debugger. All calls to the RAW API must be on the same thread.
> Each socket must be used from within one thread (well..., but let's keep
> it simple, and I'm no expert on this)
Geschickt flexibel verbunden – jetzt auch mit IO-Link: der neue elektronische Sicherungsautomat Typ REX12 http://www.e-t-a.de/NEU_REX12/
A neat and smart connection – available with IO-Link: the new electronic circuit protector REX12 http://www.e-t-a.de/NEW_REX12/
E-T-A Elektrotechnische Apparate GmbH
Geschäftsführer: Dr. Clifford Sell
Sitz der Gesellschaft: Altdorf bei Nürnberg, Registergericht HR B 377