MC68181 Datasheet, PDF (116/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

MC68181
Freescale Semiconductor, Inc.
Using the Receiver Shutdown Packet
c. The temporary address is found in the assigned frame and it is a
fragmented message. In this case, the host must follow the rules for
Operation of a Fragmented Message and determine the proper time to
stop the All Frame mode operation. In this case, the host must write to the
“DAF” bit with a “1” and the appropriate “DTA” bit with a “1” in the All
Frame Mode Register in order to terminate both the fragmented message
and the temporary address.
5. The above operation is repeated for every temporary address.
USING THE RECEIVER SHUTDOWN PACKET
Calculating Time Left
The receiver shutdown packet gives timing information to the host. Two times are of
particular interest when implementing a roaming algorithm.
• TimeToWarmUpStart is defined as the amount of time there is before the
receiver will start to warm up (i.e. transition from the off state to the first
warm up state).
• TimeToTasksDisabled is defined as the amount of time the host has to complete
any host initiated tasks (e.g. by setting SND or SAS in the roaming control
packet).
• The formulas for calculating these times depend on whether the FLEXchip is
in synchronous mode or asynchronous mode.
SYNCHRONOUS MODE:
TimeToWarmUpStart ≥ (TNF ⋅ 80ms) + (SkippedFrames ⋅ 1874.375ms) + ReceiverOffTime – 167.5ms
TimeToTasksDisabled ≥ (TNF ⋅ 80ms) + (SkippedFrames ⋅ 1874.375ms) – 247.5ms
ASYNCHRONOUS MODE:
TimeToWarmUpStart ≥ ((TNF – 2) ⋅ 80ms) + ReceiverOffTime
TimeToTasksDisabled ≥ ((TNF – 3) ⋅ 80ms)
C-12
MC68181 Technical Data Sheet
For More Information On This Product,
Go to: www.freescale.com
MOTOROLA