MC68181 Datasheet, PDF (115/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

Freescale Semiconductor, Inc.
MC68181
Operation of a Temporary Address
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 temporary address must be disabled by the host after the message is
completed.
The FLEX protocol specifies sixteen addresses for the dynamic group call, which may
be temporarily activated in a specific future frame (If the designated frame 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 and remaining valid throughout the following frames to the
completion of the message. If the message is not found in the specified frame (frame
defined by a full 7-bit frame number), the host must disable the assigned temporary
address.
The following describes the sequence of events between the Host and the FLEXchip
IC required to handle a temporary address:
1. Following an Address Packet, the host will receive a Vector Packet with
V₂V₁V₀ = 001 and i₂i₁i₀ = 000 for a Short Instruction Vector indicating a
temporary address has been assigned to this pager. The vector packet will
indicate which temporary address is assigned and the frame in which the
temporary address is expected.
2. The FLEXchip IC will increment the corresponding temporary address
counter and begin to decode all of the following frames.
3. The FLEXchip IC 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.
4. There are several scenarios that may occur with temporary addresses.
a. The temporary address is not found in the frame assigned and therefore
the host must terminate the Temporary Address mode by sending an All
Frame Mode Packet to the FLEXchip IC with the “DTA” bit of the
particular temporary address set.
b. 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 FLEXchip IC
with the “DTA” bit of the particular temporary address set.
MOTOROLA
MC68181 Technical Data Sheet
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