Releases the SPI peripheral.
This function releases the SPI peripheral lock, allowing other threads to use it. See Synchronizing Access to Shared System Resources section for additional information on shared resource locks.
// SYNTAX SPI.endTransaction();
Returns: Negative integer in case of an error.
Note that you must use the same
SPI object as used with
SPI.begin() so if you used
SPI1.begin() also use