ST STM32F205 series Reference Manual page 79

RM0033
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)
b)
•
To wake up the device from the Standby mode with an RTC tamper or time stamp
event, it is necessary to:
a)
b)
•
To wake up the device from the Standby mode with an RTC wakeup event, it is
necessary to:
a)
b)
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)
b)
c)
d)
e)
•
When using RTC wakeup to wake up the device from the low-power modes:
a)
b)
c)
d)
e)
•
When using RTC tamper to wake up the device from the low-power modes:
a)
b)
c)
d)
e)
• When using RTC time stamp to wake up the device from the low-power modes:
a)
b)
c)
Enable the RTC alarm interrupt in the RTC_CR register
Configure the RTC to generate the RTC alarm
Enable the RTC time stamp interrupt in the RTC_CR register or the RTC tamper
interrupt in the RTC_TAFCR register
Configure the RTC to detect the tamper or time stamp event
Enable the RTC wakeup interrupt in the RTC_CR register
Configure the RTC to generate the RTC wakeup event
Disable the RTC alarm interrupt (ALRAIE or ALRBIE bits in the RTC_CR register)
Clear the RTC alarm (ALRAF/ALRBF) flag
Clear the PWR Wakeup (WUF) flag
Enable the RTC alarm interrupt
Re-enter the low-power mode
Disable the RTC Wakeup interrupt (WUTIE bit in the RTC_CR register)
Clear the RTC Wakeup (WUTF) flag
Clear the PWR Wakeup (WUF) flag
Enable the RTC Wakeup interrupt
Re-enter the low-power mode
Disable the RTC tamper interrupt (TAMPIE bit in the RTC_TAFCR register)
Clear the Tamper (TAMP1F/TSF) flag
Clear the PWR Wakeup (WUF) flag
Enable the RTC tamper interrupt
Re-enter the low-power mode
Disable the RTC time stamp interrupt (TSIE bit in RTC_CR)
Clear the RTC time stamp (TSF) flag
Clear the PWR Wakeup (WUF) flag
RM0033 Rev 8
Power control (PWR)
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