MEC1322 Datasheet, PDF (242/456 Pages) Microchip Technology – Keyboard and Embedded Controller for Notebook PC

MEC1322
Note:
An Alarm that is set inside the hour after the time specified in this register will not be triggered, because
that one-hour period is skipped. This period includes the exact time (0 minutes: 0 seconds) given by this
register, through the 59 minutes: 59 seconds point afterward.
19.11.18 DAYLIGHT SAVINGS BACKWARD REGISTER
Offset ^1Ch
Bits
Description
31 DST_BACKWARD_AM_PM
This bit selects AM vs. PM, to match bit[7] of the Hours register if 12-
Hour mode is selected in Register B at the time of writing.
30:24 DST_BACKWARD_HOUR
This field holds the matching value for bits[6:0] of the Hours register.
The written value will be interpreted according to the 24/12 Hour
mode and DM mode settings at the time of writing.
23:19 Reserved
18:16 DST_BACKWARD_WEEK
This value matches an internally-maintained week number within the
current month. Valid values for this field are:
Type
R/W
R/W
R
R/W
5=Last week of month
4 =Fourth week of month
3=Third week of month
2=Second week of month
1=First week of month
15:11 Reserved
R
10:8 DST_BACKWARD_DAY_OF_WEEK
R/W
This field matches the Day of Week Register bits[2:0].
7:0 DST_BACKWARD_MONTH
R/W
This field matches the Month Register.
Default
0b
Reset
Event
RTC_R
ST
00h
RTC_R
ST
-
-
0h
RTC_R
ST
-
-
0h
RTC_R
ST
00h
RTC_R
ST
This is a 32-bit register, accessible also as individual bytes. When writing as individual bytes, ensure that the DSE bit
(in Register B) is off first, or that the block is disabled or stopped (SET bit), to prevent a time update while this register
may have incompletely-updated contents.
When enabled by the DSE bit in Register B, this register defines an hour and day of the year at which the Hours register
increment will be inhibited from occurring. After triggering, this feature is automatically disabled for long enough to
ensure that it will not retrigger the second time this Hours value appears, and then this feature is re-enabled automati-
cally.
There are no don’t-care fields recognized. All fields must be already initialized to valid settings whenever the DSE bit is
‘1’.
Fields other than Week and Day of Week use the current setting of the DM bit (binary vs. BCD) to interpret the informa-
tion as it is written to them. Their values, as held internally, are not changed by later changes to the DM bit, without
subsequently writing to this register as well.
Note:
An Alarm that is set inside the hour before the time specified in this register will be triggered twice, because
that one-hour period is repeated. This period will include the exact time (0 minutes: 0 seconds) given by
this register, through the 59 minutes: 59 seconds point afterward.
DS00001719D-page 242
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