ISD94100 Series Technical Reference Manual
Sep 9, 2019
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The RTC controller provides time alarm mask register (RTC_TAMSK register) and calendar alarm
mask register (RTC_CAMSK register) to mask the specified digit and generate periodic interrupt
without changing the alarm match condition in RTC_TALM and RTC_CALM registers in each alarm
interrupt service routine.
6.11.5.9 Application Note
1.
All data in RTC_TALM, RTC_CALM, RTC_TIME and RTC_CAL registers are all expressed
in BCD format.
2.
User has to make sure that the loaded values are reasonable. For example, Load RTC_CAL
as 201a (year), 13 (month), 00 (day), or RTC_CAL does not match with RTC_WEEKDAY,
etc.
3.
In RTC_CAL and RTC_CALM, only 2 BCD digits are used to express “year”. The 2 BCD
digits of xy means 20xy, rather than 19xy or 21xy.
4.
Example of 12-Hour Time Setting
If current RTC time is PM12:59:30 in 12-Hour Time Scale mode, the RTC_TIME setting as:
HOUR:
RTC_TIME[21:16]: 0x32 (0x12+0x20) combined by TENHR (RTC_TIME[21:20]) is 0x3, HR
(RTC_TIME[19:16]) is 0x2.
MIN:
RTC_TIME[14:8]: 0x59 combined by TENMIN (RTC_TIME[14:12]) is 0x5, MIN
(RTC_TIME[11:8]) is 0x9.
SEC:
RTC_TIME[6:0]: 0x30 combined by TENSEC (RTC_TIME[6:4]) is 0x3, SEC
(RTC_TIME[3:0]) is 0x0.
5.
Registers value after powered on:
Register
Reset State
RTC_INIT
0
RTC_RWEN
0
RTC_CAL
15/8/8 (year/month/day)
RTC_TIME
00:00:00 (hour : minute : second)
RTC_CALM
00/00/00 (year/month/day)
RTC_TALM
00:00:00 (hour : minute : second)
RTC_CLKFMT
1 (24-hour mode)
RTC_WEEKDAY
6 (Saturday)
RTC_INTEN
0
RTC_INTSTS
0
RTC_LEAPYEAR
0
RTC_TICK
0
Table 6.11.5-3 Registers value after power-on