MC68181 Datasheet, PDF (101/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

Freescale Semiconductor, Inc.
MC68181
Decoder-to-Host Packet Descriptions
when the FLEX chip IC is reset and when the FLEX chip IC is turned off by clearing
the ON bit in the Control Packet.
CURRENT FRAME NUMBER (f)
This value is updated every frame regardless of whether the FLEX chip IC needs to
decode the frame. This value will change to its proper value for a frame at the end of
block 0 of the frame. The value of these bits is not guaranteed when FIV is 0.
SYNCHRONOUS MODE (SM)
This bit is set when the FLEX chip IC is synchronous to the system. The FLEX chip IC
will set this bit when the first synchronization words are received. It will clear this bit
when synchronization to the FLEX signal is lost. This bit is initialized to 0 when the
FLEX chip IC is reset and when it is turned off by clearing the ON bit in the Control
Packet.
LOW BATTERY (LB)
The LB bit is set to the value last read from the LOBAT pin. The host controls when
the LOBAT pin is read via the Receiver Control Packets. This bit is initialized to 0 at
reset. It is also initialized to the inverse of the LBP bit in the Configuration Packet
when the FLEX chip IC is turned on by setting the ON bit in the Control Packet.
CURRENT SYSTEM CYCLE NUMBER (c)
This value is updated every frame regardless of whether the FLEX chip IC needs to
decode the frame.This value will change to its proper value for a frame at the end of
block 0 of the frame. The value of these bits is not guaranteed when FIV is 0.
SYNCHRONOUS MODE UPDATE (SMU)
The SM bit is set if the SM bit has been updated in this packet. When the FLEX chip IC
is turned on, this bit will be set when the first synchronization words are found (SM
changes to 1) or when the first synchronization search window after the FLEX chip IC
is turned on expires (SM stays 0). The latter condition gives the host the option of
assuming the paging device is in range when it is turned on, and displaying out-of-
range only after the initial A search window expires. After the initial Synchronous
mode update, the SMU bit will be set whenever the FLEX chip IC transitions from/to
Synchronous mode. Cleared when read. Changes in the SM bit due to turning off the
FLEX chip IC will not cause the SMU bit to be set. This bit is initialized to 0 when the
FLEX chip IC is reset.
LOW BATTERY UPDATE (LBU)
The LBU bit is set if the value on two consecutive reads of the LOBAT pin yielded
different results and is cleared when read. The host controls when the LOBAT pin is
read via the Receiver Control Packets. Changes in the LB bit due to turning on the
FLEX chip IC will not cause the LBU bit to be set. This bit is initialized to 0 when the
FLEX chip IC is reset.
MOTOROLA
MC68181 Technical Data Sheet
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