SPI, Nrf24 and ethernet shield r3 on mega, it works, but why?

Hi! I am making a nrf24 logging arduino that shows data on a html page, i was worried about the 5100 bug that keeps the SPI bus from switching between devices, i have also read that you must manage the device selection pin to change device.

I tried to mix two examples, the nrf scanner and the arduino web server, i compiled it without managing any switch pin and i was expecting only one device to work properly, maybe the first that was activated. Instead of that i got a fully functional scanner and the analog readings on the web page, this is so strange, i was expecting a lot of troubles and i have read many pages on the forums that this combination poses some problems. But it works!

Should i expect some side effects/strange problems/hangs?

I don't see any problem with the w5100. It works with other SPI devices just fine.

Ok today i tried to combine my sketch based on rf24network and the same arduino web server example.
Now i can’t receive messages from leaf nodes, but the ethernet part works, i tried putting high the pin 10 and low the CSN pin of the nrf24 module but nothing is happening.

It only works if i get off the ethernet shield. (without changing code).

It’s very strange since basically the two sketches are very similar and the old one correctly reports free and busy channels on the radio network.

It only works if i get off the ethernet shield. (without changing code).

What does that mean? Are you leaving the code in the sketch and removing the shield?

Does the rf24 library depend on interrupts to work? If the rf24 library is not IDE v1.6.x compatible, that could be the problem. The new IDE allows SPI devices to use interrupts, but they must "register" with the SPI library to use interrupts.

edit: An easy way to tell if it uses interrupts is the INT pin on the nrf24 board. Does it connect to D2 or D3 on the Arduino?