FSK Modem and DTMF Codec
CMX865
3.
Signal List
CMX865D2
Pin No.
1
2
3
Signal
Name
XTALN
XTAL/CLOCK
RDRVN
Type
O/P
I/P
O/P
The output of the on-chip Xtal oscillator inverter.
The input to the oscillator inverter from the Xtal
circuit or external clock source.
Relay drive output, low resistance pull down to
V
SS
when active and medium resistance pull up
to V
DD
when inactive.
The negative supply rail (ground).
Schmitt trigger input to the Ring signal detector.
Connect to V
SS
if Ring Detector not used.
Open drain output and Schmitt trigger input
forming part of the Ring signal detector. Connect
to V
DD
if Ring Detector not used.
The positive supply rail. Levels and thresholds
within the device are proportional to this voltage.
The output of the Rx Input Amplifier.
The inverting input to the Rx Input Amplifier
The non-inverting input to the Rx Input Amplifier
Internally
generated
bias
voltage
of
approximately V
DD
/2, except when the device is
in ‘Powersave’ mode when V
BIAS
will discharge
to V
SS
. Should be decoupled to V
SS
by a
capacitor mounted close to the device pins.
The inverted output of the Tx Output Buffer.
The non-inverted output of the Tx Output Buffer.
The C-BUS chip select input from the
µC.
The C-BUS serial data input from the
µC.
The C-BUS serial clock input from the
µC.
A 3-state C-BUS serial data output to the
µC.
This output is high impedance when not sending
data to the
µC.
A ‘wire-ORable’ output for connection to a
µC
Interrupt Request input. This output is pulled
down to V
SS
when active and is high impedance
when inactive. An external pullup resistor is
required i.e. R1 of Figure 2.
Description
4, 8, 12, 17, 21
5
6
V
SS
RD
RT
Power
I/P
BI
7, 16, 24
9
10
11
13
V
DD
RXAFB
RXAN
RXA
V
BIAS
Power
O/P
I/P
I/P
O/P
14
15
18
19
20
22
TXAN
TXA
CSN
COMMAND
DATA
SERIAL
CLOCK
REPLY DATA
O/P
O/P
I/P
I/P
I/P
T/S
23
IRQN
O/P
©
2005 CML Microsystems Plc
4
D/865/3
CMLMICRO [ CML MICROCIRCUITS ]
