MCIMX27 Datasheet, PDF (1247/1650 Pages) Freescale Semiconductor, Inc – Multimedia Applications Processor

Real Time Clock (RTC)
0x1000_7024 (DAYALARM)
Access: User read/write
31
30
29
28
27
26
25
24
23
22
21
20
19
18
R0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset 0
0
0
0
0
0
0
0
0
0
0
0
0
0
17
16
0
0
0
0
15
14
R
W
Reset 0
0
Field
31–16
15–0
DAYSAL
13
12
11
10
9
8
7
6
5
4
3
2
DAYSAL
1
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 33-12. RTC Day Alarm Register
0
0
Table 33-14. RTC Day Alarm Register Field Descriptions
Description
Reserved
Day Setting of the Alarm. Indicates the current day setting of the alarm. It can be set to any value
between 0 and 65535.
0x0000 current day setting of alarm is 0.
0x0001 current day setting of alarm is 1.
......
......
0xFFFF current day setting of alarm is 65535.
33.5 Functional Description
The prescaler converts the incoming crystal reference clock to a 1 Hz signal which is used to increment
the seconds, minutes, hours, and days TOD counters. The alarm functions, when enabled, generate RTC
interrupts when the TOD settings reach programmed values. The sampling timer generates
fixed-frequency interrupts, and the minute stopwatch allows for efficient interrupts on minute boundaries.
33.5.1 Prescaler and Counter
The prescaler divides the reference clock down to 1 Hz. The reference frequencies of 32.768 kHz,
38.4 kHz, and 32 kHz are supported. The prescaler stages are tapped to support the sampling timer.
The counter portion of the RTC module consists of four groups of counters that are physically located in
three registers:
• The 6-bit seconds counter is located in the SECONDS register.
• The 6-bit minutes counter and the 5-bit hours counter are located in the HOURMIN register.
• The 16-bit day counter is located in the DAYR register.
These counters cover a 24-hour clock over 65536 days. All three registers can be read or written at any
time.
MCIMX27 Multimedia Applications Processor Reference Manual, Rev. 0.2
Freescale Semiconductor
33-17