Datasheet

PCF85063TP All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 3 — 11 July 2013 17 of 47
NXP Semiconductors
PCF85063TP
Tiny Real-Time Clock/calendar
[1] Default value.
8.3.1.1 OS: Oscillator stop
When the oscillator of the PCF85063TP is stopped, the OS flag is set. The oscillator can
be stopped, for example, by connecting one of the oscillator pins OSCI or OSCO to
ground. The oscillator is considered to be stopped during the time between power-on and
stable crystal resonance. This time can be in the range of 200 ms to 2 s depending on
crystal type, temperature, and supply voltage.
The flag remains set until cleared by command (see Figure 10
). If the flag cannot be
cleared, then the oscillator is not running. This method can be used to monitor the
oscillator and to determine if the supply voltage has reduced to the point where oscillation
fails.
Table 20. Seconds coded in BCD format
Seconds value in
decimal
Upper-digit (ten’s place) Digit (unit place)
Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
00
[1]
0000000
01 0000001
02 0000010
: :::::::
09 0001001
10 0010000
: :::::::
58 1011000
59 1011001
Fig 10. OS flag
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