Using SPI to multiple device

Question

As we know that, to connecting Arduino Uno with Ethernet Shield (W5100) is using pin 10, 11, 12, 13 (SPI). Is it possible to use Arduino Uno SPI to state up multiple Ethernet Shields? (at least 2 Ethernet Shields)

Thank you.

Answer 1

I think what you want is a software SPI implementation - there are several libraries that do that for you:

https://github.com/niteris/ArduinoSoftSpi

https://github.com/greiman/DigitalIO

are two examples (there are numerous others - google "Arduino software spi"). Software SPI allows you to talk to SPI devices on pins other than the ones defined by the hardware.

You'll probably need to modify the ethernet library to make it work with software SPI, however - that is a different question beyond the scope of this one.