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 30 of 78
NXP Semiconductors
PCF8523
Real-Time Clock (RTC) and calendar
[1] The correction pulses on pin INTx are
1
⁄
4096
s wide. For multiple pulses, they are repeated at an interval of
1
⁄
2048
s.
In MODE = 1, clock outputs and timer source clocks affected by the clock correction are
as shownin Table 33
.
8.8.3 Offset calibration workflow
The calibration offset has to be calculated based on the time. Figure 18 shows the
workflow how the offset register values can be calculated:
Table 32. Correction pulses for MODE = 1
Correction value Update every n
th
minute
Second Correction pulses on
INT1 per second
[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 58 1
2592
+62 or 62 2 00 to 58 1
2592
+63 or 63 2 00 to 58 1
2594
64 2 00 to 58 1
2595
Table 33. Effect of clock correction for MODE = 1
CLKOUT frequency (Hz) Effect of correction Timer source clock
frequency (Hz)
Effect of
correction
32768 no effect 4096 no effect
16384 no effect 64 affected
8192 no effect 1 affected
4096 no effect
1
⁄
60
affected
1024 no effect
1
⁄
3600
affected
32 affected - -
1affected--