DS_S5T8702 Datasheet, PDF (54/62 Pages) Samsung semiconductor – FEEX ALPHANUMERIC DECODER II

S5T8702
FEEX^TM ALPHANUMERIC DECODER II
OPERATION OF A TEMPORARY ADDRESS
GROUP MESSAGING
The FLEX protocol allows for a dynamic group call for the purpose of sending a common message to a group of
paging devices. The dynamic group call approach assigns a "Temporary Address" using the personal address
and the short instruction vector.
The FLEX protocol specifies sixteen addresses for the dynamic group call which may be temporarily activated in
a future frame (If the frame or one of the frames designated is equal to the present frame the host is to interpret
this as the next occurrence of this frame 4 minutes in the future.) The temporary address is valid for one
message starting in the specified frame(s) and remaining valid throughout the following frames to the completion
of the message. If the message is not found in the specified frame(s) the host must disable the assigned
temporary address.
The following describes the sequence of events between the Host and the S5T8702 required to handle a
temporary address:
• Following an Address Packet, the host will receive a Vector Packet with V₂V₁V₀ = 001 and i₂i₁i₀ = 000 or 010
(a Short Instruction Vector indicating a temporary address has been assigned to this pager). The system may
send either i₂i₁i₀ = 000 or i₂i₁i₀ = 010 or both when assigning a temporary address. The vector packet with
i₂i₁i₀ = 000 will indicate which temporary address is assigned and the frame in which the temporary address is
expected. The vector packet with i₂i₁i₀ =010 will indicate which temporary address is assigned, the MSb of
the expected frame (essentially indicating 64 frames in which to look for the temporary address), and a
message sequence number. When the vector packet with i₂i₁i₀ = 010 is received on a long address, the
specific assign frame is included in the message word sent after the vector
• The S5T8702 will increment the corresponding temporary address counter for each temporary address
assignment vector received and begin to decode all of the following frames. Note that this implies a single
dynamic group assignment that is implemented by sending two short instructions ( one for each temporary
address assignment mode of the short instruction vector) will cause the corresponding temporary address
counter to increment twice.
• The S5T8702 continues to decode all of the frames and passes any address information, vector information
and message information to the host followed by a status packet indicating the end of each frame and the
current frame number.
• There are several scenarios which may occur with temporary addresses
1.
The temporary address is not found in the any of the assigned frames and therefore the host
must terminate the temporary address mode by sending an All Frame Mode Packet to the
S5T8702 with the "DTA" bit of the particular temporary address set. (if both temporary address
assignment packets were used to assign the temporary address, the "DTA" bit must be set twice
to disable the temporary address)
2.
The temporary address is found in the frame it was assigned and was not a fragmented message.
Again, the host must terminate the temporary address mode by sending an All Frame Mode
Packet to the S5T8702 with the "DTA" bit of the particular temporary address set.(if both
temporary address assignment packets were used to assign the temporary address, the "DTA" bit
must be set twice to disable the temporary address)
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