#define BMM150_I2C_ADDR(SEL) (0x20 + 2*(SEL))
BMM150_I2C_ADDR defines the default 8-bit I2C address for the device as specified in the datasheet for the selection pins CSB:SDO pulled low or high. The standard 8-bit addresses are 0x20, 0x22, 0x24, and 0x26.