
RM0008
Real-time clock (RTC)
Doc ID 13902 Rev 12
465/1096
18.2 RTC
main
features
●
Programmable prescaler: division factor up to 2
20
●
32-bit programmable counter for long-term measurement
●
Two separate clocks: PCLK1 for the APB1 interface and RTC clock (must be at least
four times slower than the PCLK1 clock)
●
The RTC clock source could be any of the following ones:
–
HSE clock divided by 128
–
LSE oscillator clock
–
LSI oscillator clock (refer to
for details)
●
Two separate reset types:
–
The APB1 interface is reset by system reset
–
The RTC Core (Prescaler, Alarm, Counter and Divider) is reset only by a Backup
domain reset (see
Section 7.1.3: Backup domain reset on page 88
).
●
Three dedicated maskable interrupt lines:
–
Alarm interrupt, for generating a software programmable alarm interrupt.
–
Seconds interrupt, for generating a periodic interrupt signal with a programmable
period length (up to 1 second).
–
Overflow interrupt, to detect when the internal programmable counter rolls over to
zero.