CMX860
Telephone Signalling
Transceiver
D/860/5 January 2002
Provisional Issue
Features
•
•
•
•
•
•
•
•
V.23 & Bell 202 FSK Tx and Rx
DTMF/Tones Transmit and Receive
Line and Phone Complementary Drivers
Call Progress Decoder
Dual Tone Detection and Generation
Simple 'C-BUS' Serial Interface
Low Power Operation
‘Powersave’ Standby Mode
Applications
•
•
•
•
•
•
•
•
Least Cost Routers
Vending Machines
Internet Appliances
Home Management Systems
Remote Meter Reading
Alarm Systems
Cable TV Set-Top Boxes
Advanced Feature Phones
1.1
Brief Description
The CMX860 is a flexible, low-power Telephone Signalling Transceiver IC, designed for use in a wide
range of line-powered telephone equipment. The IC combines the functions of a DTMF encoder and
decoder, V.23 / Bell 202 modulator and demodulator plus call progression circuitry with analogue
switching between line and phone interfaces. Ring detection, local phone off-hook detection and a relay
driver for line hook-switch operation are also provided under the control of 'C-BUS'. The ring and hook
detectors operate whilst the remainder of the IC is powersaved, generating an interrupt to wake-up the
host µC when further processing or signalling is required.
All on-chip functions and switching arrangements are controlled via a serial bus ('C-BUS'). The CMX860
is designed to operate at 2.7V and utilises CML’s low power DTMF decoder and V.23 / Bell 202 modem
technology. It is available in 28-pin SOIC (D1), TSSOP (E1) and SSOP (D6) packages.
©
2002 Consumer Microcircuits Limited
Telephone Signalling Transceiver / Least Cost Router
CMX860
CONTENTS
Section
1.0
1.1
1.2
1.3
1.4
Page
Features and Applications .................................................................. 3
Brief Description.................................................................................. 3
Block Diagram ..................................................................................... 5
Signal List ............................................................................................ 6
External Components.......................................................................... 8
1.4.1 Ring Detector Interface......................................................... 10
1.4.2 Hook Detector Interface ........................................................ 11
1.4.5 RESETN pin........................................................................... 11
General Description........................................................................... 12
1.5.1 Tx USART .............................................................................. 13
1.5.2 FSK Modulator ...................................................................... 14
1.5.3 Tx Filter and Equaliser.......................................................... 14
1.5.4 DTMF/Tones Generator ........................................................ 14
1.5.5 Tx Level Control and Output Drivers ................................... 14
1.5.6 DTMF Decoder and Tone Detectors..................................... 15
1.5.7 Rx Modem Filter and Equaliser ............................................ 16
1.5.8 FSK Demodulator.................................................................. 16
1.5.9 Rx Data Register and USART ............................................... 16
1.5.10 Rx Modem Pattern Detectors................................................ 18
1.5.11 Analogue Signal Routing ..................................................... 18
1.5.12 'C-BUS' Interface ................................................................... 19
1.5.12.1
General Reset Command.............................. 19
1.5.12.2
General Control Register.............................. 21
1.5.12.3
Transmit Mode Register ............................... 23
1.5.12.4
Receive Mode Register ................................. 26
1.5.12.5
Tx Data Register............................................ 28
1.5.12.6
Rx Data Register ........................................... 28
1.5.12.7
Analogue Signal Path Register .................... 29
1.5.12.8
Status Register.............................................. 30
1.5.12.9
Programming Register.................................. 33
1.5.12.10
Other Registers ............................................. 35
Application Notes .............................................................................. 36
Performance Specification................................................................ 37
1.7.1 Electrical Performance.......................................................... 37
1.7.1.1 Absolute Maximum Ratings..................................... 37
1.7.1.2 Operating Limits....................................................... 37
1.7.1.3 Operating Characteristics ........................................ 38
1.5
1.6
1.7
©
2002 Consumer Microcircuits Limited
4
D/860/5
Telephone Signalling Transceiver / Least Cost Router
CMX860
1.2
Block Diagram
Figure 1 Block Diagram
©
2002 Consumer Microcircuits Limited
5
D/860/5
Telephone Signalling Transceiver / Least Cost Router
CMX860
1.3
Signal List
CMX860
D6, D1, E1
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
DV
SS
when active and medium resistance pull up
to DV
DD
when inactive.
The digital negative supply rail (ground).
Schmitt trigger input to the Ring signal detector.
Connect to DV
SS
if Ring Detector not used.
Open drain output and Schmitt trigger input
forming part of the Ring signal detector. Connect
to DV
DD
if Ring Detector not used.
An active-low reset pin.
The output of the Line Rx Input Amplifier.
The inverting input to the Line Rx Input Amplifier.
The non-inverting input to the Line Rx Input
Amplifier.
The output of the Phone Rx Input Amplifier.
The inverting input to the Phone Rx Input
Amplifier.
The non-inverting input to the Phone Rx Input
Amplifier.
The analogue negative supply rail (ground).
Internally generated bias voltage of approximately
AV
DD
/2, except when the device is in
‘Powersave’ mode when V
BIAS
will discharge to
AV
SS
. Should be decoupled to AV
SS
by a
capacitor mounted close to the device pins.
The inverted output of the Phone Tx Output
Driver.
The non-inverted output of the Phone Tx Output
Driver.
The inverted output of the Line Tx Output Driver.
The non-inverted output of the Line Tx Output
Driver.
The analogue positive supply rail. Levels and
thresholds within the device are proportional to
this voltage.
Open drain output and Schmitt trigger input
forming part of the Hook signal detector. Connect
to DV
DD
if Hook Detector not used.
Description
4
5
6
DV
SS
RD
RT
Power
I/P
BI
7
8
9
10
11
12
13
14
15
RESETN
LINERXF
LINERXN
LINERXP
PHONERXF
PHONERXN
PHONERXP
AV
SS
V
BIAS
I/P
O/P
I/P
I/P
O/P
I/P
I/P
Power
O/P
16
17
18
19
20
PHONETXN
PHONETXP
LINETXN
LINETXP
AV
DD
O/P
O/P
O/P
O/P
Power
21
HT
BI
©
2002 Consumer Microcircuits Limited
6
D/860/5
Telephone Signalling Transceiver / Least Cost Router
CMX860
CMX860
D6, D1, E1
Pin No.
22
23
24
25
26
Signal
Name
HD
CSN
COMMAND
DATA
SERIAL
CLOCK
REPLY DATA
Type
I/P
I/P
I/P
I/P
T/S
Description
Schmitt trigger input to the Hook signal detector.
Connect to DV
SS
if Hook Detector not used.
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 DV
SS
when active and is high impedance
when inactive. An external pullup resistor is
required i.e. R1 of Figure 2.
The digital positive supply rail. Levels and
thresholds within the device are proportional to
this voltage.
27
IRQN
O/P
28
DV
DD
Power
I/P = Input O/P = Output BI = Bidirectional T/S = 3-state Output NC = No Connection
©
2002 Consumer Microcircuits Limited
7
D/860/5
微控制器 MCU
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
