Real-time Clock (RTC)
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11
Real-time Clock (RTC)
11.1
Product Overview
11.1.1
Introduction
The real-time clock (RTC) is an independent binary coded decimal (BCD) timer/counter. One 32-bit register contains the seconds, minutes,
hours (12- or 24-hour format) expressed in BCD format. One 32-bit register contains the days expressed in binary format.
Daylight saving time compensation can be performed.
Additional two 32-bit registers contain the programmable alarm seconds, minutes, hours and days.
A digital calibration feature is available to compensate for some deviation.
After backup domain reset, all RTC registers are protected against possible parasitic write accesses.
As long as the supply voltage remains in the operating range, the RTC never stops, regardless of the device status, that is run mode, low power
mode or under reset.
11.1.2
Features
Time with seconds, minutes, hours (12- or 24-hour format) and days
Daylight saving compensation programmable by software
One programmable alarm with interrupt function. The alarm can be triggered by any combination of the time fields.
Maskable interrupt/event:
Alarm
Digital calibration circuit
Register write protection
11.1.3
Block Diagram
The RTC is connected under APB buses. The total block diagram is shown in Fig 11-1.
rtc_reg
rtc_apbslv_wrapper
rtc_clk_rst_gen
rtc_counter
rtc_ctrl
rtc_alarm
rtc_clk_div_apre
rtc_clk_div_spre
APB Bus
Fig 11-1 RTC block diagram
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2019-05-15 10:08:03