RegOpMode - IoTThinks/EasyLoRa GitHub Wiki
RegOpMode has 7 bits from 0 to 7. The value is in binary.

From Sandeep's LoRa library, The definition of RegOpMode in hex.

Set mode for SX1278.
- MODE_LONG_RANGE_MODE = 0x80 (hex) = 1000 0000 (Binary)
- MODE_TX = 0x03 (hex) = 11 (Binary)
- MODE_LONG_RANGE_MODE | MODE_TX = 1000 0011 (Binary)
