Real-time clock (RTC)
RM0365
745/1080
DocID025202 Rev 7
27.6.4 RTC
initialization
and
status register (RTC_ISR)
This register is write protected (except for RTC_ISR[13:8] bits). The write access procedure
is described in
RTC register write protection on page 729
Address offset: 0x0C
Backup domain reset value: 0x0000 0007
System reset: not affected except INIT, INITF, and RSF bits which are cleared to ‘0’
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
Res.
RECALPF
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
TAMP3F TAMP2F TAMP1F TSOVF
TSF
WUTF ALRBF ALRAF
INIT
INITF
RSF
INITS
SHPF WUTWF
ALRB
WF
ALRAWF
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rc_w0
rw
r
rc_w0
r
r
r
r
r
Bits 31:17 Reserved, must be kept at reset value
Bit 16
RECALPF
: Recalibration pending Flag
The RECALPF status flag is automatically set to ‘1’ when software writes to the RTC_CALR
register, indicating that the RTC_CALR register is blocked. When the new calibration settings
are taken into account, this bit returns to ‘0’. Refer to
Bit 15
TAMP3F
: RTC_TAMP3 detection flag
This flag is set by hardware when a tamper detection event is detected on the RTC_TAMP3
input.
It is cleared by software writing 0
Bit 14
TAMP2F
: RTC_TAMP2 detection flag
This flag is set by hardware when a tamper detection event is detected on the RTC_TAMP2
input.
It is cleared by software writing 0
Bit 13
TAMP1F
: RTC_TAMP1 detection flag
This flag is set by hardware when a tamper detection event is detected on the RTC_TAMP1
input.
It is cleared by software writing 0
Bit 12
TSOVF
: Time-stamp overflow flag
This flag is set by hardware when a time-stamp event occurs while TSF is already set.
This flag is cleared by software by writing 0. It is recommended to check and then clear
TSOVF only after clearing the TSF bit. Otherwise, an overflow might not be noticed if a time-
stamp event occurs immediately before the TSF bit is cleared.
Bit 11
TSF
: Time-stamp flag
This flag is set by hardware when a time-stamp event occurs.
This flag is cleared by software by writing 0.
Bit 10
WUTF
: Wakeup timer flag
This flag is set by hardware when the wakeup auto-reload counter reaches 0.
This flag is cleared by software by writing 0.
This flag must be cleared by software at least 1.5 RTCCLK periods before WUTF is set to 1
again.