I've cross-posted this on the Adafruit support forums as well, but I'll ask here in case it's something on the uC...
I have a Netduino Plus 2 with two MAX31855 thermocouple breakout boards and a 2.2" colour LCD breakout, all from Adafruit. The LCD works just peachy on its own. However, if the SClk pins for either of the Max31855 boards are connected, then it seems that one or two spurious clock pulses are generated when trying to read from the LCD, one extra clock pulse per SPI read/write call (I use 2 calls, as there is an 8-bit 'dummy' read needed), which seem to happen *before* data is read in from the LCD.
These extra clock pulses do not happen if the LCD is the only device connected to the SPI bus' SClk line. Is there any reason the N+2 would/could produce extra clock pulses when additional devices are added on to the SPI bus, that I could look for in my circuit?