SPEAR1310 datasheet(49/57 Pages) STMICROELECTRONICS

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SPEAr1310

Real-time clock (RTC)

Doc ID 17528 Rev 4

49/57

Real-time clock (RTC)

The RTC is a block that keeps track of the real time of day. It also functions as an alarm and

a calendar. The time is displayed in 24-hour format, and time/calendar values are stored in

binary-coded decimal format.

The time of day, alarm and calendar, status and control registers can all be accessed via a

standard 32 APB bus. All read/write operations last 2 cycles.

RTC provides a self isolation mode that is activated during power down. This feature allows

RTC to continue working if power is not supplied to the rest of the circuit. This feature is

realized by supplying separate power and clock connections.

A set of 16 general purpose registers (GP-Reg) are provided which can be used to save

data during the power down state.GP-Reg-set runs on 32 K oscillator clock and powered by

RTC battery. Each register is 32-bit and addressed mapped on the 32-bit APB bus. A bit in

status register reflects the status of any pending write to GP-Reg-set. This means that write

operation to the GP-Reg-set should be sequential, so you should wait for this pending

status bit to be cleared before writing again to GP-Reg-set.

33.1

Main features

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Works on dedicated 32768 Hz external clock and power supply

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9999- year calendar

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Leap years support

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Programmable alarm interrupt

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Power management and self-isolation

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Prescaler and timer registers bypass for TEST

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Time and date update monitors

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16 general purpose registers which can be used to save data during power down state.

SPEAR1310 Folha de dados(PDF) 49 Page - STMicroelectronics