399
/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Main function
Description
Alarm
Programmable alarm clock and interrupt function. The alarm can be triggered by any combination of
the calendar fields. When the alarm event occurs the alarm flag can be sent to GPIO through
“RTC_OUT”, and it also can be used to wake up the CPU or exit from the low power status such as
SLEEP, STOP0, STOP2 and STANDBY modes.
Timestamp
Time-stamp function for GPIO event saving.
Interrupts/events
Alarm A/Alarm B interrupt/event
Wakeup interrupt/event
Timestamp interrupt/event
RTC function description
14.2.1
RTC block diagram
Figure 14-1 RTC Block Diagram
RTC includes the following functions:
Alarm A and Alarm B event/interrupt
Timestamp event/interrupt
RTC output functions
256 Hz or 1Hz clock output (LSE frequency is 32.768 kHz).
LSI
LSE
RTC_OUT
Synchronous
15 Bits prescaler
BCD
Calendar
Asynchronous
7 Bits prescaler
RTCCLK
RTC_SUBS
ck_apre
Default value
256Hz
ck_spre
Default value
1Hz
Timestamp
register
TISF
Prescale
2
、
4
、
8
、
16
WKUPSEL[2:0]
16 bits wakeup
automatic reload timer
RTC_WKUPT
Output
Control
HSE/128
WTF
Alarm A
Alarm B
=
=
ALAF
ALBF
OUTSEL[1:0]
RTC_CALIB
RTC_ALARMx
EXTI0
EXTI1
EXTI15
...
Calibration
20bits counter
Shadow register
RTC_TSH
RTC_DATE