I use the MATLAB® Support Package for Arduino® Hardware to control devices with SPI communication. Matlab r2014b version with an Arduino uno.
It seems that modifying the mode has no effect. Setting mode to 0 should idle clock low and setting it to 3 for example should idle clock high. But it doesn't...
a = arduino('com9'); dev = spidev(a, 4, 'mode', 0);