Real-time clock (RTC)
RM0090
824/1731
DocID018909 Rev 11
26.6.18 RTC alarm A sub second register (RTC_ALRMASSR)
Address offset: 0x44
Backup domain reset value: 0x0000 0000
System reset: not affected
Bit 1
TAMP1TRG
: Active level for tamper 1
if TAMPFLT != 00
0: TAMPER1 staying low triggers a tamper detection event.
1: TAMPER1 staying high triggers a tamper detection event.
if TAMPFLT = 00:
0: TAMPER1 rising edge triggers a tamper detection event.
1: TAMPER1 falling edge triggers a tamper detection event.
Caution:
When TAMPFLT = 0, TAMP1E must be reset when TAMP1TRG is changed to avoid
spuriously setting TAMP1F.
Bit 0
TAMP1E
: Tamper 1 detection enable
0: Tamper 1 detection disabled
1: Tamper 1 detection enabled
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
MASKSS[3:0]
Reserved
r
r
r
r
rw
rw
rw
rw
r
r
r
r
r
r
r
r
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Reserved
SS[14:0]
r
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
w
rw
rw
Bits 31:28 Reserved
Bits 27:24
MASKSS[3:0]
: Mask the most-significant bits starting at this bit
0: No comparison on sub seconds for Alarm A. The alarm is set when the seconds unit is
incremented (assuming that the rest of the fields match).
1: SS[14:1] are don’t care in Alarm A comparison. Only SS[0] is compared.
2: SS[14:2] are don’t care in Alarm A comparison. Only SS[1:0] are compared.
3: SS[14:3] are don’t care in Alarm A comparison. Only SS[2:0] are compared.
...
12: SS[14:12] are don’t care in Alarm A comparison. SS[11:0] are compared.
13: SS[14:13] are don’t care in Alarm A comparison. SS[12:0] are compared.
14: SS[14] is don’t care in Alarm A comparison. SS[13:0] are compared.
15: All 15 SS bits are compared and must match to activate alarm.
The overflow bits of the synchronous counter (bits 15) is never compared. This bit can be
different from 0 only after a shift operation.
Bits 23:15 Reserved
Bits 14:0
SS[14:0]
: Sub seconds value
This value is compared with the contents of the synchronous prescaler’s counter to
determine if Alarm A is to be activated. Only bits 0 up MASKSS-1 are compared.