Advanced Configuration and Power Interface Specification

Advanced Configuration and Power Interface Specification
Buffer(){
WORD Year; // 1900 - 9999
BYTE Month; // 1 - 12
BYTE Day; // 1 - 31
BYTE Hour; // 0 - 23
BYTE Minute; // 0 - 59
BYTE Second; // 0 - 59
BYTE Pad1;
WORD milliseconds, // 1-1000
WORD TimeZone; // -1440 to 1440 or 2047 (unspecified)
BYTE Daylight;
BYTE Pad2[3]; // Reserved, must be zero
}
Return Value:
An Integer:
0 - success
0xFFFFFFFF- Failed
Note: Time is maintained using a battery backed time device (e.g. a real time clock)
Note: The time will always be local time; the time zone value can be used to determine the offset from
UTC.
Note: Time zone field is the number of minutes that the local time lags behind the UTC time. (i.e. time
zone = UTC - local time). The time zone is in 2's complement format.
Note: Time zone value of 2047, means that time zone value is not specified, and no relation to UTC can
be inferred.
Note: Daylight is a bitmask containing the daylight savings time information for the time, as follows:
Bit [0]: 1 = the time is affected by daylight savings time, 0= time is not affected by daylight
savings. This value does not indicate that the time has been adjusted for daylight savings time.
It indicates only that it should be adjusted when the time enters daylight savings time.
Bit [1]: 1= the time has been adjusted for daylight savings time, 0= the time hasn't been adjusted
for daylight savings.
All other bits must be zero.
When entering daylight saving time, if the time is affected, but hasn't been adjusted (DST = 1), use
the new calculation:
• The date/time should be increased by the appropriate amount.
• The TimeZone should be decreased by the appropriate amount (EX: +480 changes to +420 when
moving from PST to PDT).
• The Daylight value changes to 3.
When exiting daylight saving time, if the time is affected and has been adjusted (DST = 3), use the
new calculation:
• The date/time should be decreased by the appropriate amount.
• The TimeZone should be increased by the appropriate amount.
• The Daylight value changes to 1.
544 April, 2015 Version 6.0