23.8.10 Alarm Value in Clock/Calendar mode (CTRLA.MODE=2)

The 32-bit value of ALARM is continuously compared with the 32-bit CLOCK value, based on the masking set by MASK.SEL. When a match occurs, the Alarm n interrupt flag in the Interrupt Flag Status and Clear register (INTFLAG.ALARM) is set on the next counter cycle, and the counter is cleared if CTRLA.MATCHCLR is '1'.
Name: ALARM
Offset: 0x20
Reset: 0x00000000
Property: PAC Write-Protection, Write-Synchronized

Bit 3130292827262524 
 YEAR[5:0]MONTH[3:2] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 2322212019181716 
 MONTH[1:0]DAY[4:0]HOUR[4] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 15141312111098 
 HOUR[3:0]MINUTE[5:2] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 
Bit 76543210 
 MINUTE[1:0]SECOND[5:0] 
Access R/WR/WR/WR/WR/WR/WR/WR/W 
Reset 00000000 

Bits 31:26 – YEAR[5:0] Year

The alarm year. Years are only matched if MASK.SEL is 6

Bits 25:22 – MONTH[3:0] Month

The alarm month. Months are matched only if MASK.SEL is greater than 4.

Bits 21:17 – DAY[4:0] Day

The alarm day. Days are matched only if MASK.SEL is greater than 3.

Bits 16:12 – HOUR[4:0] Hour

The alarm hour. Hours are matched only if MASK.SEL is greater than 2.

Bits 11:6 – MINUTE[5:0] Minute

The alarm minute. Minutes are matched only if MASK.SEL is greater than 1.

Bits 5:0 – SECOND[5:0] Second

The alarm second. Seconds are matched only if MASK.SEL is greater than 0.