I have trouble connecting to multiple SPI units. More specifically to SCP1000 and the Ethernet shield. The Ethernet shield works when both are connected but then I don't get any values from the SCP1000 chip. Removing the Ethernet library from SW does not help, I have to remove the Ethernet shield module completely for the SCP1000 to work.
I have connected the Chip Select pins to two different pins on the Arduino and they are not enabled at the same time but still without success.
Have anyone else tried to combine the Ethernet Shield with other SPI units?
Or can anyone tip me about a SPI library that uses other pins than the hardware SPI pins. (I don't think I need the full speed of the HW SPI pins anyway).
The official ethernet shield does not play well with others. The Wiznet chip is not a well behaved SPI peripheral in that it does not put MISO in a high impedance state when its CS input is inactive. It has a separate "SPI enable" input that does that. The official ethernet shield simply ties SPI enable high, so that MISO is always active.
Your choices are to do some hardware hacking on the ethernet shield, or move the other peripheral to other pins and bit-bang SPI on those pins.
Looks at the MCP3208 example on the playground for an example of bit-banged (i.e. software) SPI. While the example does use the standard SPI hardware pins, there's no reason for it to do so.