PCF2123BS/1 NXP Semiconductors, PCF2123BS/1 Datasheet - Page 33

• Manufacturer Part Number: PCF2123BS/1
• Manufacturer: NXP Semiconductors

Specifications of PCF2123BS/1

• Lead Free Status / Rohs Status: Compliant

NXP Semiconductors
PCF2123
Product data sheet
Fig 20. STOP bit functional diagram
OSCILLATOR
8.11 STOP bit function
The function of the STOP bit is to allow for accurate starting of the time circuits. The STOP
bit function will cause the upper part of the prescaler (F
thus no 1 Hz ticks will be generated. The time circuits can then be set and will not
increment until the STOP bit is released (see
The STOP bit function will not affect the output of 32.768 kHz, 16.384 kHz, or 8.192 kHz
(see
The lower two stages of the prescaler (F
is asynchronous to the crystal oscillator, the accuracy of re-starting the time circuits will be
between 0 and one 8.192 kHz cycle (see
The first increment of the time circuits is between 0.499878 s and 0.500000 s after STOP
bit is released. The uncertainty is caused by the prescaler bits F
(see
Fig 21. STOP bit release timing
Section
Table
40).
stop released
8.8).
All information provided in this document is subject to legal disclaimers.
8192 Hz
F
0
Rev. 5 — 27 April 2011
OSCILLATOR STOP
F
1
DETECTOR
RESET
F
2
0
Figure
and F
16384 Hz
1024 Hz
8192 Hz
0 μs to 122 μs
Figure 21
1 Hz
oscillator stop flag
1
21).
) are not reset and because the SPI-bus
RESET
F
13
2
and
to F
CLKOUT source
SPI Real time clock/calendar
Table
14
RESET
) to be held in reset and
F
0
14
and F
40).
001aai556
PCF2123
001aaf912
© NXP B.V. 2011. All rights reserved.
1 Hz tick
stop
1
not being reset
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