I set the configuration follow the datasheet
This routine assumes a ±2 g measurement range and operation in wake-up mode.
1. Write 250 decimal (0xFA) to Register 0x20, and write 0 to Register 0x21: sets activity threshold to 250 mg.
2. Write 150 decimal (0x96) to Register 0x23, and write 0 to Register 0x24: sets inactivity threshold to 150 mg.
3. Write 30 decimal (0x1E) to Register 0x25: sets inactivity timer to 30 samples or about 5 seconds.
4. Write 0x3F to Register 0x27: configures motion detection in loop mode and enables referenced activity and inactivity detection.
5. Write 0x40 to Register 0x2B: map the AWAKE bit to INT2. The INT2 pin is tied to the gate of the switch.
6. Write 0x0A to Register 0x2D: begins the measurement in wake-up mode.
Then i read the registor 0x0A by loop.I always read 0x7f when i put the board on the desk with the surface with characters upwards.But according to the datasheet 1LSB means 1mg when in ±2 g measurement range,0x7f means 2032~2047 (0x7f0~0x7ff),almost 2g.I can't understand this data,why can be this ???