ST STM32L0x3 User Manual

Real-time clock (RTC) RM0367
654/1043 RM0367 Rev 7
The RTC includes:
• Two alarms
• Up to three tamper events from I/Os
– Tamper detection erases the backup registers.
• One timestamp event from I/O
• Tamper event detection can generate a timestamp event
• 5 x 32-bit backup registers
• Output functions: RTC_OUT which selects one of the following two outputs:
– RTC_CALIB: 512 Hz or 1Hz clock output (with an LSE frequency of 32.768 kHz).
This output is enabled by setting the COE bit in the RTC_CR register.
– RTC_ALARM: This output is enabled by configuring the OSEL[1:0] bits in the
RTC_CR register which select the Alarm A, Alarm B or Wakeup outputs.
• Input functions:
– RTC_TS: timestamp event
– RTC_TAMP1: tamper1 event detection
– RTC_TAMP2: tamper2 event detection
– RTC_TAMP3: tamper3 event detection (only on category 5 devices).
– RTC_REFIN: 50 or 60 Hz reference clock input
27.4.2 GPIOs controlled by the RTC
RTC_OUT, RTC_TS and RTC_TAMP1 are mapped on the same pin (PC13). PC13 pin
configuration is controlled by the RTC, whatever the PC13 GPIO configuration, except for
the RTC_ALARM output open-drain mode.
The output mechanism follows the priority order shown in Table 117.
Table 117. RTC pin PC13 configuration
(1)
PC13 Pin
configuration
and function
OSEL[1:0]
bits
(RTC_ALARM
output
enable)
COE bit
(RTC_CALIB
output
enable)
RTC_OUT
_RMP
bit
RTC_ALARM
_TYPE
bit
TAMP1E bit
(RTC_TAMP1
input
enable)
TSE bit
(RTC_TS
input
enable)
RTC_ALARM
output OD
01 or 10 or 11 Don’t care
0
0 Don’t care Don’t care
1
RTC_ALARM
output PP
01 or 10 or 11 Don’t care
0
1 Don’t care Don’t care
1
RTC_CALIB
output PP
00 1 0 Don’t care Don’t care Don’t care
RTC_TAMP1
input floating
00 0 Don’t care
Don’t care 1 000 1
1
01 or 10 or 11 0

ST STM32L0x3 Specifications

General

Brand	ST
Model	STM32L0x3
Category	Microcontrollers
Language	English