Q1. The accelerometer comes with user-selectable g ranges, e.g. +/- 2g, +/- 4g.
How do I go about changing from the default range, +/- 2g to say +/- 16g?
2. How do I change the output data rate from the default 100Hz?
A1. How to set the different ranges of ADXL345 is described in page 27 of the
datasheet rev c. In Table 21 "g Range Setting" you find the settings.
You’ve found the definitions in the .h file. You can follow the format of the
other register writes to write this one as well.
buffer = XL345_DATA_FORMAT; /* Set register address */
buffer = XL345_RANGE_2G; /* Set value */
xl345Write(2,buffer); /* Write register */
put these 3 lines where you want this configured; a good place to start is just
before the Tap Configuration section.
2. The datarate is changed when changing the value of BW_RATE. In table 7 and 8
date code vs. output datarate is listed. More details regard register BW_RATE
are shown in table 19 of datasheet.