Low Power V.32 bis Modem
CMX869
3.
Signal List
CMX869
D2/E2/P4
Signal
Description
Pin No.
Name
Type
REPLY DATA
TS
1
A 3-state C-BUS serial data output to the µC. This
output is high impedance when not sending data to the
µC.
RDRVN
OP
Relay Drive output, low resistance pull down to VSS
when active and medium resistance pull up to VDD
when inactive.
2
SERIAL
CLOCK
IP
IP
4
5
The C-BUS serial clock input from the µC.
COMMAND
DATA
The C-BUS serial data input from the µC.
CSN
RXA
IP
IP
IP
6
8
9
The C-BUS chip select input from the µC.
The non-inverting input to the Rx Input Amplifier
RXBN
A second, switched inverting input to the Rx Input
Amplifier. Used to increase the input stage gain. If not
required, leave this pin unconnected.
RXAN
IP
The inverting input to the Rx Input Amplifier
10
11
13
RXAFB
OP
OP
The output of the Rx Input Amplifier.
V
BIAS
Internally generated bias voltage of approximately
AV /2, except when the device is in ‘Powersave’
DD
mode when V
will discharge to AV . Must be
BIAS
SS
decoupled to AV by a capacitor mounted close to the
SS
device pins.
TXAN
TXA
OP
OP
IP
The inverted output of the Tx Output Buffer.
14
15
17
The non-inverted output of the Tx Output Buffer.
Schmitt trigger input to the (inverting) Ring signal
RDN
detector. Connect to DV if Ring Detector is not used.
DD
-
NC
Reserved for future use. Do not connect to this pin.
18
20
V
PWR/ Internally generated 2.5V supply voltage. Must be
DEC
OP
decoupled to DV by capacitors mounted close to the
SS
device pins. No other connections allowed.
The input to the oscillator inverter from the Xtal circuit
or external clock source.
XTAL/CLOCK
IP
21
XTALN
IRQN
OP
OP
The output of the on-chip Xtal oscillator inverter.
22
24
A ‘wire-ORable’ output for connection to a µC Interrupt
Request input. This output is pulled down to DVSS
when active and is high impedance when inactive. An
external pullup resistor is required ie R1 of Figure 2
© 2004 CML Microsystems Plc
4
D/869/4
CMLMICRO [ CML MICROCIRCUITS ]
