All registers reset to their Reset Values after a period of I2C inactivity (15-20mins), or after a period when set to Measurement Mode (0-60s), or seemingly at random. What can cause this?
Having not used this device before so I don't know what to expect. I've just fired it up on I2C and standard address (58). I can read all the Regisrters 0 & 29 to 57, getting the Reset Values shown in Table 19 of the ADXL345 Data Sheet. I can also set register values and read XYZ values, getting reasonably sensible results, e.g. the vector sum is 1g when static, so the internals seem to be working OK.