Consumer Microcircuits Limited FX949L6, FX949L4 Datasheet

CML Semiconductor Products
CDPD Wireless Modem Data Pump FX949
D/949/5 March 1996
1.0 Features Advance Information
•• MES Full Duplex Operation •• 19.2kb/s GMSK Modulation
•• Forward Channel Decoding •• Sleep Timer Included
•• Reverse Channel Encoding •• 3.3V and 5V Applications
1.1 Brief Description
The FX949 is a low power CMOS integrated circuit which performs all of the real-time signal and data format-management functions required for full-duplex operation of a CDPD Mobile End Station.
The FX949 interfaces directly with the analogue modulation and demodulation circuits of the radio and the host radio/application processor bus.
It accepts application data from the processor, constructs a correct Reverse Channel packet containing this data and converts the packet to GMSK analogue signals for transmission. In receive, Forward Channel GMSK signals from the discriminator are demodulated, the packet disassembled, error checked, and the recovered application data passed to the processor.
The FX949 is the cost, size, and power efficient alternative to DSP design solutions in high performance OEM products for the Cellular Digital Packet Data wireless services.
1996 Consumer Microcircuits Limited
CDPD Wireless Modem Data Pump FX949
CONTENTS
Section Page
1.0 Features..........................................................................................................1
1.1 Brief Description............................................................................................1
1.2 Block Diagram................................................................................................3
1.3 Signal List.......................................................................................................4
1.4 External Components....................................................................................6
1.5 General Description.......................................................................................9
1.5.1 Software Description ....................................................................... 9
1.6 Application Notes........................................................................................14
1.6.1 General..........................................................................................14
1.6.2 Transmitter (reverse channel).......................................................14
1.6.3 Receiver (forward channel)...........................................................15
1.6.4 Timer .............................................................................................16
1.7 Performance Specification .........................................................................18
1.7.1 Electrical Performance .................................................................. 18
1.7.2 Packaging......................................................................................23
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CDPD Wireless Modem Data Pump FX949
1.2 Block Diagram
Figure 1 Block Diagram
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CDPD Wireless Modem Data Pump FX949
µ
µ
1.3 Signal List
PackageL4Package
L6
Signal Description
Pin No. Pin No. Name Type
2 8 D0 BI ) 3 9 D1 BI ) 4 10 D2 BI ) 5 11 D3 BI
) 8-bit bidirectional tristate 7 12 D4 BI ) data lines. 8 13 D5 BI ) 9 14 D6 BI )
10 15 D7 BI ) 12 17 V
DD
Power The positive supply rail. Levels and voltages are
dependent upon this supply. This pin should be
decoupled to V
13 18 V
BIAS
O/P A bias line for the internal circuitry, held at
½ V
capacitor mounted close to the device pins (see
Figures 2 and 3).
14 19 RX SIGNAL
FEEDBACK
O/P The output of the Rx input amplifier and the input
to the Rx filter.
P interface
by a capacitor.
SS
. This pin must be decoupled by a
DD
15 20 RX SIGNAL I/P The inverting input to the Rx input amplifier. 16
17
21 22
DOC 1 DOC 2
O/P O/P
) Connections to the Rx level measurement
) circuitry. A capacitor should be connected
) from each pin to V
SS
. 18 23 TX SIGNAL O/P The inverted Tx signal output from the modem. 20 24 V
ss
Power The negative supply rail (ground). 26 31 XTALN O/P The inverted output of the on-chip oscillator. 27 32 CLOCK/XTAL I/P The input to the on-chip oscillator, for external
Xtal circuit or clock.
32 36 IRQN O/P A 'wire-ORable' output for connection to the
controlling output has a low impedance pull down to V
P's Interrupt Request input. This
SS
when active and is high impedance when inactive.
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CDPD Wireless Modem Data Pump FX949
µ
µ
PackageL4Package
L6
Signal Description
Pin No. Pin No. Name Type
33 37 CSN I/P Chip Select. An active low logic level input to the
modem, used to enable a data read or write operation.
34 38 WRN I/P Write. An active low logic level input used to
control the writing of data into the modem from the controlling
P.
35 39 RDN I/P Read. An active low logic level input used to
control the reading of data from the modem into the controlling
P.
38 41 A6 I/P ) 39 42 A5 I/P ) 43 1 A4 I/P ) 44 2 A3 I/P ) 7 logic level modem register address select 45 3 A2 I/P ) inputs. 46 4 A1 I/P ) 47 5 A0 I/P )
1, 6, 11, 19, 24, 30, 36, 37,
6, 7, 16, 28, 30, 40,
43, 44
40, 41,
42, 48
21, 22, 23, 25, 28, 29,
31
25, 26, 27, 29, 33, 34,
35
Notes: I/P = Input
O/P = Output BI = Bidirectional
) ) ) No internal connection: leave open circuit. ) ) )
) ) Internally connected: leave open circuit. ) )
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1.4 External Components
Figure 2 Recommended External Components (L4)
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Figure 3 Recommended External Components (L6)
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Figure 4 Internal Block Diagram
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