MC68181 Datasheet, PDF (70/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

MC68181
Freescale Semiconductor, Inc.
Host-to-Decoder Packet Descriptions
Table B-6 SP Bit Definition
SP₁
SP₀
Signal Polarity
EXTS1 EXTS0
FSK Modulation
@ SP = 0,0
EXTS1 EXTS0
0
0
Normal Normal
+4800 Hz
1
0
0
1
Normal Inverted
+1600 Hz
1
1
1
0
Inverted Normal
–1600 Hz
0
1
1
1
Inverted Inverted
–4800 Hz
0
0
SYNCHRONOUS MODE ENABLE (SME)
When this bit is set, a Status Packet will be automatically sent whenever the SMU
(Synchronous Mode Update) bit in the Status Packet is set. The host can use the SM
(Synchronous Mode) bit in the Status Packet as an in-range/out-of-range indication.
The value after reset = 0.
MAXIMUM OFF TIME (MOT)
This bit has no effect if AST in the Timing Control Packet is non-zero. When AST = 0
and MOT = 0, asynchronous A-word searches will time-out in 4 minutes. When
AST = 0 and MOT = 1, asynchronous A-word searches will time-out in 1 minute.
(value after reset = 0)
CLOCK OUTPUT DISABLE (COD)
When this bit is clear, a 38.4 kHz signal will be output on the CLKOUT pin. When this
bit is set, the CLKOUT pin will be driven low. Note that setting and clearing this bit
can cause pulses on the CLKOUT pin that are less than one half the 38.4 kHz period.
Also note that when the clock output is enabled, the CLKOUT pin will always output
the 38.4 kHz signal even when the FLEX chip IC is in reset (as long as the FLEX chip
IC oscillator is seeing clocks). The value after reset = 0.
MINUTE TIMER ENABLE (MTE)
When this bit is set, a Status Packet will be sent at one minute intervals with the MT
(Minute Time-out) bit in the Status Packet set. When this bit is clear, the internal one-
minute timer stops counting. The internal one-minute timer is reset when this bit is
changed from 0 to 1 or when the MTC (Minute Timer Clear) bit in the Control Packet
is set. The value after reset = 0.
LOW BATTERY POLARITY (LBP)
This bit defines the polarity of the FLEX chip ICs LOBAT pin. The LB bit in the Status
Packet is initialized to the inverse value of this bit when the FLEX chip IC is turned on
(by setting the ON bit in the Control Packet). When the FLEX chip IC is turned on, a
low battery update is sent to the host in the Status Packet when a low battery
condition is detected on the LOBAT pin. Setting this bit means that a high on the
LOBAT pin indicates a low voltage condition. The value after reset = 0.
B-10
MC68181 Technical Data Sheet
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