Hi Petr,
A software reset can be activated by setting the RST bit in the CTRL_REG2 register in both Standby and Active modes. The boot mechanism resets all registers and loads them with their default values that are shown in Table 12 of the data sheet. It takes approximately 350us (500us max) and is the same for all MMA845xQ accelerometers.
Let me know if you have any other questions.
Regards,
Tomas
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