Real-time Clock (RTC)
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237
11.3.3
RTC Initialization and Status Register (RTC_ISR)
Name:
RTC initialization and status register
Size:
32 bits
Address offset:
0x08
Reset value:
0x0000 0000
The ALMF bit can be written without unlocking the write protection. Two APB clock cycles after programming it to 1, this bit is cleaned.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
RSVD
RECALPF
R
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DOVTHF
RSVD
ALMF
INIT
INITF
RSF
INITS
RSVD
ALMWF
R/W1C
R/W1C
R/W
R
R/W1C
R
R
Bit
Name
Access
Reset
Description
31:17
RSVD
N/A
-
Reserved
16
RECALPF
R
0
Recalibration pending Flag
The RECALPF status flag is automatically set to ‘1’ when software writes to the RTC_CALIBR
register, indicating that the RTC_CALIBR register is blocked. When the new calibration settings
are taken into account, this bit returns to ‘0’. Refer to Re-calibration on-the-fly.
15
DOVTHF
R/W1C
0
Day over threshold flag
This flag is set by hardware when the Day[8:0] in RTC_TR over the DAY_THRES[8:0] set in
RTC_CR register.
14:9
RSVD
N/A
-
Reserved
8
ALMF
R/W1C
0
Alarm flag
This flag is set by hardware when the time register (RTC_TR) match the alarm registers
(RTC_ALMR1L and RTC_ALMR1H).
7
INIT
R/W
0
Initialization mode
0: Free running mode
1: Initialization mode used to program time and date register (RTC_TR), and prescaler
register (RTC_PRER). Counters stop and start counting from the new value when INIT is
set.
6
INITF
R
0
Initialization flag
When this bit is set to 1, the RTC is in initialization state, and the time, date and prescaler
registers can be updated.
0: Calendar registers update isn’t allowed
1: Calendar registers update is allowed
5
RSF
R/W1C
0
Registers synchronization flag
This bit is set by hardware each time the calendar registers are copied into the shadow registers
(RTC_TR). This bit is cleared by hardware in initialization mode or when in bypass shadow
register mode (BYPSHAD=1). This bit can also be cleared by software.
It is cleared either by software or by hardware in initialization mode.
0: Calendar shadow registers hasn’t yet synchronized
1: Calendar shadow registers has synchronized
4
INITS
R
0
This bit is set by hardware when the calendar day field is different from 0 (RTC domain reset
state).
0: Calendar hasn’t been initialized
1: Calendar has been initialized
3:1
RSVD
N/A
-
Reserved
0
ALMWF
R
0
Alarm write flag
This bit is set by hardware when alarm values can be changed, after the ALME bit has been set
to 0 in RTC_CR register.
It is cleared by hardware when ALME bit has been set to 1 in RTC_CR register.
0: Alarm update isn’t allowed
1: Alarm update is allowed
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2019-05-15 10:08:03