STR720 datasheet(157/401 Pages) STMICROELECTRONICS

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STR720 - REAL TIME CLOCK (RTC)

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Bit 15:0 = RTCA[47:32]: RTC Alarm High

Reading RTCA_H register, the high part of alarm time is returned. To write this register it is

required to enter into configuration mode (see RTOFF bit of RTCCR register).

RTCP: RTC Periodic value registers

These registers keep the period counting value of the RTC periodic tick. It is write protected

by bit RTOFF of RTCCR register, write operation is allowed if RTOFF value is ‘1’. They are

used to strobe a periodic interrupt signal, RTC_PerIT, each time the counter counts down from

the RTCP value. When it reaches this threshold it resets itself and begins again. This signal is

independent of the other system interrupts in terms of alignment. The reset value sets the

period of the programmable tick is returned.

Note

If the RTCP registers are loaded with the value 00000000h then the periodic

interrupt will always be high until the register is loaded with a different periodic value.

RTCP_L

Address Offset: 1Ch

Reset value: 8000h

Bit 15:0 = RTCP[15:0]: RTC Periodic Low

Reading RTCP_L register, the low part of current RTCP counter value is returned. To write

this register it is required to enter into configuration mode (see RTOFF bit of RTCCR register).

RTCP_H

Address Offset: 20h

Reset value: 0000h

Bit 15:4 = Reserved. These bits must always be written to ‘0’.

Bit 3:0 = RTCP[19:16]: RTC Periodic High

Reading RTCP_H register, the high part of current RTCP counter value is returned. To write

this register it is required to enter into configuration mode (see RTOFF bit of RTCCR register).

765432

RTCP[15:0]

765432

Reserved

RTCP[19:16]

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