OSCILLATOR CONTROL BITS When the DS12887 is shipped from the factory, the internal oscillator is turned off. This feature prevents the lithium energy cell from being used until it is installed in a system. A pattern of 010 in bits 4 through 6 of Register A turns the oscillator on and enables the countdown chain. A pattern of 11X turns the oscillator on, but holds the countdown chain of the oscillator in reset. All other combinations of bits 4 through 6 keep the oscillator off.