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Real-Time Clock
Freescale Semiconductor
28-9
28.3.8
RTC Stopwatch Minutes Register (RTC_STPWCH)
The stopwatch minutes register contains the current stopwatch countdown value. When the minute counter
of the TOD clock increments, value in this register decrements.
28.3.9
RTC Days Counter Register (RTC_DAYS)
The RTC_DAYS register programs the day for the TOD clock. When the RTC_HOURMIN[HOUR] field
rolls over from 23 to 0, the day counter increments. It can be read or written at any time. After a write, the
time changes to the new value. This register cannot be reset because the real-time clock is always enabled
at reset. Only 16-bit accesses to this register are allowed.
28.3.10 RTC Day Alarm Register (RTC_ALRM_DAY)
The RTC_ALRM_DAY register configures the day for the alarm. The alarm settings can be read or written
at any time.
Address: 0xFC03_C01C (RTC_STPWCH)
Access: User read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
CNT
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1
Figure 28-9. RTC Stopwatch Minutes Register (RTC_STPWCH)
Table 28-10. RTC_STPWCH Field Descriptions
Field
Description
31–6
Reserved, must be cleared.
5–0
CNT
Stopwatch count. Contains the stopwatch countdown value plus one minute. Stopwatch counter decrements by the
minute (MIN) tick output from the RTC_HOURMIN register, so the average tolerance of the count is 0.5 minutes.
For better accuracy, enable the stopwatch by polling the RTC_ISR[MIN] bit or via the minute interrupt service
routine.
Note:
Write the value of one less than the desired stopwatch timeout.
Address: 0xFC03_C020 (RTC_DAYS)
Access: User read/write
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
R 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
DAYS
W
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Figure 28-10. RTC Days Counter Register (RTC_DAYS)
Table 28-11. RTC_DAYS Field Descriptions
Field
Description
31–16
Reserved, must be cleared.
15–0
DAYS
Current day count. Set to any value between 0 and 65,535 (0xFFFF).
Содержание MCF54455
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