
Real-time clock (RTC)
RM0453
1012/1454
RM0453 Rev 2
32.6.3
RTC sub second register (RTC_SSR)
Address offset: 0x08
Backup domain reset value: 0x0000 0000
System reset value: 0x0000 0000 when BYPSHAD = 0. Not affected when BYPSHAD = 1.
32.6.4 RTC
initialization
control
and status register (RTC_ICSR)
This register is write protected. The write access procedure is described in
.
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
SS[31:16]
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
SS[15:0]
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
r
Bits 31:0
SS[31:0]
: Synchronous binary counter
SS[31:16]
: Synchronous binary counter MSB values
When Binary or Mixed mode is selected (BIN = 01 or 10 or 11):
SS[31:16] are the 16 MSB of the SS[31:0] free-running down-counter.
When BCD mode is selected (BIN=00):
SS[31:16] are forced by hardware to 0x0000.
SS[15:0]
: Sub second value/Synchronous binary counter LSB values
When Binary mode is selected (BIN = 01 or 10 or 11):
SS[15:0] are the 16 LSB of the SS[31:0] free-running down-counter.
When BCD mode is selected (BIN=00):
SS[15:0] is the value in the synchronous prescaler counter. The fraction of a second is given
by the formula below:
Second fraction = (PREDIV_S - SS) / (PR 1)
SS can be larger than PREDIV_S only after a shift operation. In that case, the correct
time/date is one second less than as indicated by RTC_TR/RTC_DR.
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.
RECAL
PF
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Res.
Res.
Res.
BCDU[2:0]
BIN[1:0]
INIT
INITF
RSF
INITS
SHPF
WUTW
F
Res.
Res.
rw
rw
rw
rw
rw
rw
r
rc_w0
r
r
r