ST STM32F412 User Manual

General-purpose I/Os (GPIO) RM0402
178/1163 RM0402 Rev 6
7.3.15 Selection of RTC additional functions
The STM32F4xx feature one GPIO pin RTC_AF1 that can be used for the detection of a
tamper or time stamp event, or RTC_ALARM, or RTC_CALIB RTC outputs.
• The RTC_AF1 (PC13) can be used for the following purposes:
RTC_ALARM output: this output can be RTC Alarm A, RTC Alarm B or RTC Wakeup
depending on the OSEL[1:0] bits in the RTC_CR register
• RTC_CALIB output: this feature is enabled by setting the COE[23] in the RTC_CR
register
• RTC_TAMP1: tamper event detection
• RTC_TS: time stamp event detection
The selection of the corresponding pin is performed through the RTC_TAFCR register as
follows:
• TAMP1INSEL is used to select which pin is used as the RTC_TAMP1 tamper input
• TSINSEL is used to select which pin is used as the RTC_TS time stamp input
• ALARMOUTTYPE is used to select whether the RTC_ALARM is output in push-pull or
open-drain mode
The output mechanism follows the priority order listed in Table 27.
Table 27. RTC additional functions
(1)
Pin
configuration
and function
enabled enabled
Tamper
enabled
Time
stamp
enabled
TAMP1INSEL
TAMPER1
pin selection
TSINSEL
TIMESTAMP
pin
selection
ALARMOUTTYP
configuration
Alarm out
output OD
1Don’t care
Don’t
care
Don’t
care
Don’t care Don’t care 0
Alarm out
output PP
1Don’t care
Don’t
care
Don’t
care
Don’t care Don’t care 1
Calibration
out output PP
01
Don’t
care
Don’t
care
Don’t care Don’t care Don’t care
TAMPER1
input floating
0 0 1 0 0 Don’t care Don’t care
TIMESTAMP
and
TAMPER1
input floating
0 0 1 1 0 0 Don’t care
TIMESTAMP
input floating
0 0 0 1 Don’t care 0 Don’t care
Standard
GPIO
0 0 0 0 Don’t care Don’t care Don’t care
1. OD: open drain; PP: push-pull.

ST STM32F412 Specifications

General

Brand	ST
Model	STM32F412
Category	Microcontrollers
Language	English