STMicroelectronics STM32F405 User Manual

DocID018909 Rev 11 139/1731
RM0090 Power controller (PWR)
149
RTC alternate functions to wake up the device from the Stop mode
• To wake up the device from the Stop mode with an RTC alarm event, it is necessary to:
a) Configure the EXTI Line 17 to be sensitive to rising edges (Interrupt or Event
modes)
b) Enable the RTC Alarm Interrupt in the RTC_CR register
c) Configure the RTC to generate the RTC alarm
• To wake up the device from the Stop mode with an RTC tamper or time stamp event, it
is necessary to:
a) Configure the EXTI Line 21 to be sensitive to rising edges (Interrupt or Event
modes)
b) Enable the RTC time stamp Interrupt in the RTC_CR register or the RTC tamper
interrupt in the RTC_TAFCR register
c) Configure the RTC to detect the tamper or time stamp event
• To wake up the device from the Stop mode with an RTC wakeup event, it is necessary
to:
a) Configure the EXTI Line 22 to be sensitive to rising edges (Interrupt or Event
modes)
b) Enable the RTC wakeup interrupt in the RTC_CR register
c) Configure the RTC to generate the RTC Wakeup event
RTC alternate functions to wake up the device from the Standby mode
• To wake up the device from the Standby mode with an RTC alarm event, it is necessary
to:
a) Enable the RTC alarm interrupt in the RTC_CR register
b) Configure the RTC to generate the RTC alarm
• To wake up the device from the Standby mode with an RTC tamper or time stamp
event, it is necessary to:
a) Enable the RTC time stamp interrupt in the RTC_CR register or the RTC tamper
interrupt in the RTC_TAFCR register
b) Configure the RTC to detect the tamper or time stamp event
• To wake up the device from the Standby mode with an RTC wakeup event, it is
necessary to:
a) Enable the RTC wakeup interrupt in the RTC_CR register
b) Configure the RTC to generate the RTC wakeup event
Safe RTC alternate function wakeup flag clearing sequence
If the selected RTC alternate function is set before the PWR wakeup flag (WUTF) is cleared,
it will not be detected on the next event as detection is made once on the rising edge.
To avoid bouncing on the pins onto which the RTC alternate functions are mapped, and exit
correctly from the Stop and Standby modes, it is recommended to follow the sequence
below before entering the Standby mode:
• When using RTC alarm to wake up the device from the low-power modes:
a) Disable the RTC alarm interrupt (ALRAIE or ALRBIE bits in the RTC_CR register)
b) Clear the RTC alarm (ALRAF/ALRBF) flag

STMicroelectronics STM32F405 Specifications

General

Brand	STMicroelectronics
Model	STM32F405
Category	Controller
Language	English