Can the uno have two SPI? I need one SPI to communicate with the ethernet shield and the other SPI to control other devices. Or would I have to use a different type of microprocessor?
You can communicate with more than one device using SPI you just need a separate enable line for each device. Otherwise you can bit bang SPI using the serial out or faster using direct port access.
Another option for when devices don't have a CS or SS input is to gate the SCK signal so only one device gets a clock signal at a time.
Rob
Is it possible to demux the enable part of the SPI since I wouldn't need to communicate SPI between the two device at the same time. I am only using the network to tell what the microprocessor to do with the other SPI device like turning it on or off or etc.
As I said you can gate (mux) the clock signal, but if the devices have SS/CS pins you don't need to as you can select them individually.
Maybe you should tell us what the devices are, and supply data sheets.
Rob
Linux4ever:
Can the uno have two SPI? I need one SPI to communicate with the ethernet shield and the other SPI to control other devices. Or would I have to use a different type of microprocessor?
You can have as many SPI devices as you want, provided you have spare slave select pins. Typically you bring a dedicated SS pin low for one device, keeping the other ones high. Devices which are not selected keep the MISO line high-impedance.
So certainly you can do it. There is an Ethernet shield with an SD card that does exactly that.