Datasheet

301
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
16.6.6 RTC Calendar Alarm Register
Name: RTC_CALALR
Address: 0x400E1474
Access: Read/Write
This register can only be written if the WPEN bit is cleared in the System Controller Write Protection Mode Register
(SYSC_WPMR).
Note: To change one of the DATE, MONTH fields, it is recommended to disable the field before changing the value and
then re-enable it after the change has been made. This requires up to three accesses to the RTC_CALALR. The first
access clears the enable corresponding to the field to change (DATEEN, MTHEN). If the field is already cleared, this
access is not required. The second access performs the change of the value (DATE, MONTH). The third access is
required to re-enable the field by writing 1 in DATEEN, MTHEN fields.
• MONTH: Month Alarm
This field is the alarm field corresponding to the BCD-coded month counter.
• MTHEN: Month Alarm Enable
0: The month-matching alarm is disabled.
1: The month-matching alarm is enabled.
•DATE: Date Alarm
This field is the alarm field corresponding to the BCD-coded date counter.
• DATEEN: Date Alarm Enable
0: The date-matching alarm is disabled.
1: The date-matching alarm is enabled.
31 30 29 28 27 26 25 24
DATEEN – DATE
23 22 21 20 19 18 17 16
MTHEN – – MONTH
15 14 13 12 11 10 9 8
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