Datasheet

PCF8523 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 6 — 17 September 2013 29 of 78
NXP Semiconductors
PCF8523
Real-Time Clock (RTC) and calendar
[1] The correction pulses on pin INT1 are
1
⁄
64
s wide.
In MODE = 0, any timer or clock output using a frequency below 64 Hz is affected by the
clock correction (see Table 31
).
8.8.2 Correction when MODE = 1
The correction is triggered once per minute and then correction pulses are applied once
per second up to a maximum of 60 pulses. When correction values greater than 60 pulses
are used, additional correction pulses are made in the 59
th
second.
Clock correction is made more frequently in MODE = 1; however, this can result in higher
power consumption.
Table 30. Correction pulses for MODE = 0
Correction value Update every n
th
hour Minute Correction pulses on
INT1 per minute
[1]
+1 or 12 00 1
+2 or 2 2 00 and 01 1
+3 or 3 2 00, 01, and 02 1
::::
+59 or 59 2 00 to 58 1
+60 or 60 2 00 to 59 1
+61 or 61 2 00 to 59 1
2nd and next hour 00 1
+62 or 62 2 00 to 59 1
2nd and next hour 00 and 01 1
+63 or 63 2 00 to 59 1
2nd and next hour 00, 01, and 02 1
64 2 00 to 59 1
2nd and next hour 00, 01, 02, and 03 1
Table 31. Effect of clock correction for MODE = 0
CLKOUT frequency (Hz) Effect of correction Timer source clock
frequency (Hz)
Effect of
correction
32768 no effect 4096 no effect
16384 no effect 64 no effect
8192 no effect 1 affected
4096 no effect
1
⁄
60
affected
1024 no effect
1
⁄
3600
affected
32 affected - -
1affected--