The SPI mode controls the clock idle state and which edge clocks the data. Bit 1 is CPOL and Bit 0 is CPHA, so CPOL/CPHA for different decimal values: 0 = 0/0 = b00, 1 = 0/1 = b01, 2 = 1/0 = b10, 3 = 1/1 = b11. For CPOL and CPHA explanations, see Wikipedia article: https://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus.

• Data type: UINT16  (type index = 0)
• Readable and writable
• Default value: 0