Accelerometer
Accelerometer
The accelerometer gives the temperature and X, Y, Z accelerations.
ACCEL_DATA is a 32-bit value packing 4 independent 8-bit values
Each value is in 8-bit signed format with a range of +/- 2g. So a reading of 1g is 0x40 and -1g is 0xC0.
The sensor in fact gives a 12-bit reading, but uses only 8 bits for simplicity.
The calibration is not perfect on all boards, so do not be surprised if there is a fixed offset to all your readings.
If you want only a specific axis or temperature, use a combination of logical operators and shift e.g., extract Y using (*ACC_DATA_ADDR & 0x0000FF00) >> 8. If your processor can do lbu, the required byte can be read directly.
ACCEL_DREADY indicates data readiness, which is useful only when attempting to read at a high rate.