I have a problem with my Ethernet W5100 shield “mega compatible” (last version, with sd card)
It’s only work, if I power the Ethernet shield a few second after power on the Mega, but before the ethernet.begin()
I try the ethernet shield on both uno card and mega 2580 card, and I have the same problem, the ethernet start, send packets, but seems to never read any packet.
If I use DHCP mode, I see (network trace) the DHCP request, and the dhcp answer from the router, but the ethernet shield continue to ask dhcp.
If I use static IP, I just see the ARP request (and the ARP answer) but the ethernet shield continue to ask ARP.
If I ping the card, the card never answer to the ARP request.
(All my code was also test with a Arduino Ethernet “all-in-one” and work perfectly on that card)
Because I think about a bad connection, I try to plug the card manually
mega <-> Eth shild
SPI 50, 51, and 52 on the Mega
I have exactly the same issue with that plug
BUT, If I had a 10s delay on the code, at the very beginning, (before ethernet.begin()) and If I plug the 5V on the ethernet shield 5 seconds after power on the mega card, all work perfectly well. (ethenet & sdcard)
I don’t have the same result If I use the reset button on the ethernet shield, or send a reset by the reset PIN before ethernet.begin.
Does some one have the same issue ? Do you know any solution to do a hard reset on the ethernet shield without a manual plug/unplug ? (I can use a relay for that… but I think it’s a very dirty solution…)
Do you think my card was buggy ? (The reset don’t work)
Sorry for my bad English, I hope you understand anyway.