PCF8523 Datasheet, PDF (32/66 Pages) NXP Semiconductors – Real-Time Clock (RTC) and calendar

NXP Semiconductors
PCF8523
Real-Time Clock (RTC) and calendar
8.9.1.3 Register Tmr_A_reg
Table 35. Tmr_A_reg - timer A value register (address 11h) bit description
Bit
Symbol
Value
Description
7 to 0 TIMER_A_VALUE[7:0] 00 to FF
timer-period in seconds
timerperiod = ----------------------------ⁿ------------------------------
sourceclockfrequency
where n is the countdown value
8.9.1.4 Register Tmr_B_freq_ctrl
Table 36. Tmr_B_freq_ctrl - timer B frequency control register (address 12h) bit
description
Bit
Symbol
Value
Description
7
-
-
unused
6 to 4 TBW[2:0]
low pulse width for pulsed timer B interrupt
000^[1]
46.875 ms
001
62.500 ms
010
78.125 ms
011
93.750 ms
100
125.000 ms
101
156.250 ms
110
187.500 ms
111
218.750 ms
3
-
-
unused
2 to 0 TBQ[2:0]
source clock for timer B (see Table 38)
000
4.096 kHz
001
64 Hz
010
1 Hz
011
111^[1]
110
100
1_{60 Hz}
1_{3600 Hz}
[1] Default value.
8.9.1.5 Register Tmr_B_reg
Table 37. Tmr_B_reg - timer B value register (address 13h) bit description
Bit
Symbol
Value
Description
7 to 0 TIMER_B_VALUE[7:0] 00 to FF
timer-period in seconds
timerperiod = ----------------------------ⁿ------------------------------
sourceclockfrequency
where n is the countdown value
PCF8523
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 3 — 30 March 2011
© NXP B.V. 2011. All rights reserved.
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