*Calibration (The oscillation rate of any crystal changes with temperature. The accuracy is greatly improved by properly setting the calibration bits)
*S = SIGN bit ('1' indicates positive calibration, '0' indicates negative calibration)
*R = READ bit(Setting the READ bit to a '1' halts updates to the registers)*W = WRITE bit(Setting the WRITE bit to a '1' halts updates to the registers. The user can then load them with the correct day, date, and time data in 24-hour BCD format. Resetting the WRITE bit to a '0' then transfers the values of all registers to the actual counters and allows normal operation to resume)
== Software ==