24.9.6 Interrupt Flag Status and Clear in Clock/Calendar mode (CTRLA.MODE=2)

Note: Interrupt flags must be cleared and then read back to confirm the clear before exiting the ISR to avoid double interrupts.

Table 24-42. Register Bit Attribute Legend
Symbol	Description	Symbol	Description	Symbol	Description
R	Readable bit	HC	Cleared by Hardware	(Grey cell)	Unimplemented
W	Writable bit	HS	Set by Hardware	X	Bit is unknown at Reset
K	Write to clear	S	Software settable bit	—	—

Name:	INTFLAG
Offset:	0x0C
Reset:	0x0000
Property:	-


Bit	15	14	13	12	11	10	9	8
	OVF	TAMPER					ALARM1	ALARM0
Access	R/W	R/W					R/W	R/W
Reset	0	0					0	0


Bit	7	6	5	4	3	2	1	0
	PER7	PER6	PER5	PER4	PER3	PER2	PER1	PER0
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	0	0	0	0	0	0

Bit 15 – OVF Overflow

This flag is cleared by writing a '1' to the flag.

This flag is set on the next CLK_RTC_CNT cycle after an overflow condition occurs, and an interrupt request will be generated if INTENCLR/SET.OVF is '1'.

Writing a '0' to this bit has no effect.

Writing a '1' to this bit clears the Overflow interrupt flag.

Bit 14 – TAMPER Tamper

This flag is set after a tamper condition occurs, and an interrupt request will be generated if INTENCLR.TAMPER/INTENSET.TAMPER is '1'. Writing a '0' to this bit has no effect. Writing a '1' to this bit clears the Tamper interrupt flag.

Bits 8, 9 – ALARMn Alarm n [n=1..0]

This flag is cleared by writing a '1' to the flag.

This flag is set on the next CLK_RTC_CNT cycle after a match with the compare condition, and an interrupt request will be generated if INTENCLR/SET.ALARMn is one.

Writing a '0' to this bit has no effect.

Writing a '1' to this bit clears the Alarm n interrupt flag.

Bits 0, 1, 2, 3, 4, 5, 6, 7 – PERn Periodic Interval n [n = 7..0]

This flag is cleared by writing a '1' to the flag.

This flag is set on the 0-to-1 transition of prescaler bit [n+2], and an interrupt request will be generated if INTENCLR/SET.PERn is '1'.

Writing a '0' to this bit has no effect.

Writing a '1' to this bit clears the Periodic Interval n interrupt flag.