MC68181 Datasheet, PDF (25/119 Pages) Freescale Semiconductor, Inc – Advance Information ROAMING FLEX chip SIGNAL PROCESSOR

Freescale Semiconductor, Inc.
MC68181
Application Design Considerations
APPLICATION DESIGN CONSIDERATIONS
The FLEX™ chip IC connects to a receiver capable of converting a four-level
FSK-encoded audio signal into a 2-bit digital signal. The FLEX™ chip IC has eight
receiver control lines used for warming up and shutting down a receiver in stages.
The FLEX™ chip IC has dual bandwidth control signals for two post detection filter
bandwidths for receiving the two symbol rates of the FLEX signal. The FLEX™ chip
IC has the ability to detect a low battery signal during the receiver control sequences.
It interfaces to a host MCU through a standard SPI. It has a 38.4 kHz clock output
capable of driving other devices. It has a 1 minute timer that offers low power
support for time of day function on the host. Figure 4-1 shows a typical application
block diagram.
2/4 level
FSK RF In
LNA
MRF1047T1
MRF927T1
MRF947T1
IF STAGES
Mixer/Amp
MMBR961LT1
MR947T1
MC13143
FM IF
MC3374
MC13150
ADC
2-bit
FLEX^TM A/O
FLEX^TM
Subsystem
MC68181FDB
VCO/Buffer
Frequency
Synthesizers
Data
Rec
Audio
MC68181
SPI
Host
Processor
SPI
PLL
MRFIC0916
MRFIC0915
MRF947T1
MRF927T1
MRF2947AT1
MC141592
Figure 4-1 Roaming FLEX^TM chip System Block Diagram
MC68HC08
MC68HC11/12
MC68328
MPC821
DSP56L811
AA1216
MOTOROLA
MC68181 Technical Data Sheet
4-3
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