Attribute Settings#

Mandatory Attributes#

The mandatory attributes of the Time cluster are set as follows:

utctTime#

This is a mandatory 32-bit attribute which holds the current time (UTC). On the time-master, this attribute value is incremented once per second. On all other devices, it is the responsibility of the local application to synchronise this time with the time-master. For more information on time-synchronisation, refer to Section 18.5.

u8TimeStatus#

This is a mandatory 8-bit attribute containing the bitmap detailed in Table 28 onpage 389. This attribute must be set as follows on the time-master (Time cluster server):

The ‘Master’ bit should initially be zero until the current time has been obtained from an external time-of-day source. Once the time has been obtained and set, the ‘Master’ bit should be set (to ‘1’).
The ‘Synchronised’ bit must always be zero, as the time-master does not obtain its time from another device within the ZigBee network (this bit is set to ‘1’ only for a secondary Time cluster server that is synchronized to the time-master).
The ‘Master for Time Zone and DST’ bit must be set (to ‘1’) once the time-zone and Daylight Saving Time (DST) attributes (see below) have been correctly set for the device.

Macros are provided for setting the individual bits of the u8TimeStatus bitmap - for example, the macro CLD_TM_TIME_STATUS_MASTER_MASK is used to set the Master bit. These macros are defined in the header file time.h and are also listed in Section 18.2.

Parent topic:Attribute Settings

Optional Attributes#

The optional attributes of the Time cluster are set as follows:

i32TimeZone#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_TIME_ZONE and which indicates the local time-zone.

The local time-zone is expressed as an offset from UTC, where this offset is quantified in seconds. Therefore:

Current local standard time = utctTime + i32TimeZone

where i32TimeZone is negative if the local time is behind UTC.

u32DstStart#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_DST_START and which contains the start-time (in seconds) for daylight saving for the current year.

If u32DstStart is used then u32DstEnd and i32DstShift are also required.

u32DstEnd#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_DST_END and which contains the end-time (in seconds) for daylight saving for the current year.

If u32DstEnd is used then u32DstStart and i32DstShift are also required.

i32DstShift#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_DST_SHIFT and which contains the local time-shift (in seconds), relative to standard local time, that is applied during the daylight saving period (between u32DstStart and u32DstEnd). During this period:

Current local time = utctTime + i32TimeZone + i32DstShift

This time-shift varies between territories, but is 3600 seconds (1 hour) for Europe and North America.

If i32DstShift is used then u32DstStart and u32DstEnd are also required.

u32StandardTime#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_STANDARD_TIME and which contains the local standard time (equal to utctTime + i32TimeZone).

u32LocalTime#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_LOCAL_TIME and which contains the local time taking into account daylight saving, if applicable (equal to utctTime + i32TimeZone + i32DstShift during the daylight saving period and equal to u32StandardTime outside of the daylight saving period).

u32LastSetTime#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_LAST_SET_TIME and which indicates the most recent UTC time at which the Time attribute (utctTime) was set, either internally or over the ZigBee network.

u32ValidUntilTime#

This is an optional attribute which is enabled using the macro CLD_TIME_ATTR_VALID_UNTIL_TIME and indicates a UTC time (later than u32LastSetTime) up to which the Time attribute (utctTime) value may be trusted.