Datasheet

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STM32F765xx STM32F767xx STM32F768Ax STM32F769xx Functional overview
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2.19.3 Regulator ON/OFF and internal reset ON/OFF availability
2.20 Real-time clock (RTC), backup SRAM and backup registers
The RTC is an independent BCD timer/counter. It supports the following features:
• Calendar with subsecond, seconds, minutes, hours (12 or 24 format), week day, date,
month, year, in BCD (binary-coded decimal) format.
• Automatic correction for 28, 29 (leap year), 30, and 31 days of the month.
• Two programmable alarms.
• On-the-fly correction from 1 to 32767 RTC clock pulses. This can be used to
synchronize it with a master clock.
• Reference clock detection: a more precise second source clock (50 or 60 Hz) can be
used to enhance the calendar precision.
• Digital calibration circuit with 0.95 ppm resolution, to compensate for quartz crystal
inaccuracy.
• Three anti-tamper detection pins with programmable filter.
• Timestamp feature which can be used to save the calendar content. This function can
be triggered by an event on the timestamp pin, or by a tamper event, or by a switch to
V
BAT
mode.
• 17-bit auto-reload wakeup timer (WUT) for periodic events with programmable
resolution and period.
The RTC and the 32 backup registers are supplied through a switch that takes power either
from the V
DD
supply when present or from the V
BAT
pin.
The backup registers are 32-bit registers used to store 128 bytes of user application data
when V
DD power is not present. They are not reset by a system or power reset, or when the
device wakes up from Standby mode.
Table 4. Regulator ON/OFF and internal reset ON/OFF availability
Package Regulator ON Regulator OFF Internal reset ON Internal reset OFF
LQFP100
Yes No
Yes No
LQFP144,
LQFP208
Yes
PDR_ON set to V
DD
Yes
PDR_ON set to V
SS
LQFP176,
UFBGA176,
TFBGA100,
TFBGA216
Yes
BYPASS_REG set
to V
SS
Yes
BYPASS_REG set
to V
DD
WLCSP180 Yes
(1)
1. Available only on dedicated part number. Refer to Section 7: Ordering information.
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