W5100 (small red board) and Arduino Mega 2560

I have this great little W5100 break-out board / module which I've used already a lot in a project I'm working on with the Arduino Nano R3.

It works really nicely on the nano, runs very stable. I connect like this:

NSS > nano pin 10 MO > nano pin 11 MI > nano pin 12 SOK > nano pin 13 RST > +5v VCC > +5v GND > 0V

(info on the ebay auction says "run from 3.3v but data can run on +5v ok", however it clearly has a 3.3v regulator onboard and I've been running it fine from 5v)

However when I connect this up to my Mega 2560 I can't get it to work with my sketch.

I'm connecting of course to the Mega SPI lines, so;

NSS > mega 53 MO > mega 51 MI > mega 50 SOK > mega 52 RST > +5v VCC > +5v GND > 0V

I stripped my project back to basics and I'm testing by running the example sketch "Ethernet > Web Server" on a suitable IP address.

The lights on the W5100 breakout board seem ok, PWR and LNK are on, Rx flashes.

But I can't ping to the address, and serial monitor shows

server is at

Any ideas?

Don't connect the slave select to D53. Connect it to D10. That is where the ethernet library expects the w5100 slave select to be.

I have code around here somewhere that modifies the slave select in the library, but you shouldn't need that.

@SurferTim thank you so much. This worked. Have a pint on me!

Good deal! :) I'll have one right now.