Real-Time Clock
7-170
7.13.1 Register Descriptions
All the time and calendar information is available in dedicated registers, which
are called time and calendar registers. Time and calendar register values are
written in binary coded decimal (BCD) code (see Table 7–123).
Table 7–123. Time and Calendar Register Values
Time Unit
Range
Remarks
Year
00 to 99
Leap year: year divisible by 4
Common year: other year
Month
01 to 12
Day
01 to 31
01 to 31 for months 1, 3, 5, 7, 8, 10, 12
01 to 30 for months 4, 6, 9 ,11
01 to 29 for month 2 (leap year)
01 to 28 for month 2 (common year)
Week
00 to 06
Weekday
Hour
00 to 23
00 to 23 in 24-hour mode
01 to 12 in AM/PM mode
Minutes
00 to 59
Seconds
00 to 59
7.13.2 Register Access
There are three types of registers:
-
Time and calendar registers/alarm
-
General
-
Compensation
These three types have their own access constraints.
Access Period Violation
Disable all incoming interrupts during the register read processs
to prevent process interruption and possible violation of the
authorized 15-
µ
s access period.