Registers
1333
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Real-Time Clock (RTC)
27.3.10 Alarm Hour Register (ALARMHOUR)
NOTE:
Out of reset, the alarm hour register (ALARMHOUR) is write-protected. To disable write
protection, correct keys must be written to the KICK
n
R registers (see
).
The alarm hour register (ALARMHOUR) sets the hour value for the alarm interrupt. Hours are stored as
binary-coded decimal (BCD) format. In BCD format, the decimal numbers 0 through 9 are encoded with
their binary equivalent. The ALARMHOUR register is shown in
and described in
Figure 27-13. Alarm Hour Register (ALARMHOUR)
31
16
Reserved
R-0
15
8
7
6
5
4
3
0
Reserved
MERIDIEM
Rsvd
HOUR1
HOUR0
R-0
R/W-0
R-0
R/W-0
R/W-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 27-12. Alarm Hour Register (ALARMHOUR) Field Descriptions
Bit
Field
Value
Description
31-8
Reserved
0
Reserved.
7
MERIDIEM
Determines whether the hour is ante meridiem (AM) or post meridiem (PM) when 12-hour mode is
enabled.
0
Hour is AM
1
Hour is PM
6
Reserved
0
Reserved.
5-4
HOUR1
0-2h
Most significant digit of hours value. Range for HOUR1:HOUR0 is 00-24.
3-0
HOUR0
0-9h
Least significant digit of hours value. Range for HOUR1:HOUR0 is 00-24.