GMSK Modem Data Pump
Page 4 of 37
MX909A PRELIMINARY INFORMATION
2 Signal List
Pin No
Signal
Type
Description
1
output
This pin is a ‘wire-ORable' output for connection to the host µC's Interrupt
Request input. When active, this output has a low impedance pull down
IRQ
to V . It has a high impedance when inactive.
SS
2
3
D7
D6
D5
D4
D3
D2
D1
D0
BUS
BUS
BUS
BUS
BUS
BUS
BUS
BUS
4
Pins 2-9 (D7 - D0) are 8-bit, bi-directional, 3-state
µC interface data lines
5
6
7
8
9
10
input Read. An active low logic level input used to control the reading of data
RD
from the modem into the host µC.
11
input Write. An active low logic level input used to control the writing of data
WR
into the modem from the host µC.
V
12
13
power Negative supply. (ground).
SS
input Chip Select. An active low logic level input to the modem. It is used to
enable a data read or write operation.
CS
14
15
16
A0
A1
input Logic level modem register select input.
input Logic level modem register select input.
output Output of the on-chip oscillator.
XTAL
XTAL/CLOCK
DOC 2
17
18
input Input to the on-chip oscillator, for an external CLOCK or XTAL circuit.
output Connects to the Rx level measurement circuitry. Should be capacitive
coupled to V
.
SS
19
DOC 1
output Connects to the Rx level measurement circuitry. Should be capacitive
coupled to V
SS.
20
21
TXOUT
output Tx output signal from the modem.
A bias line for the internal circuitry, held at V /2. This pin must be
V
BIAS
output
DD
bypassed to V by a capacitor mounted close to the device pins.
SS
22
23
24
RXIN
input Input to the Rx input amplifier.
RXAMPOUT
output The output of the Rx input amplifier.
V
DD
power Positive supply. Voltage levels are dependent upon this supply. This pin
should be bypassed to V by a capacitor mounted close to the device
SS
pins.
¤2001 MX-COM, Inc.
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480134.005
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CMLMICRO [ CML MICROCIRCUITS ]
