If your program will perform SPI transactions within an interrupt, call this function to register the interrupt number or name with the SPI library. This allows SPI.beginTransaction() to prevent usage conflicts. Note that the interrupt specified in the call to usingInterrupt() will be disabled on a call to beginTransaction() and re-enabled in endTransaction().
interruptNumber: the associated interrupt number.
Corrections, suggestions, and new documentation should be posted to the Forum.
The text of the Arduino reference is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.