MX COM Inc CMX605P3, CMX605D4 Datasheet
DATA BULLETIN
CMX605
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
Digital Line to
POTS Interface
PRELIMINARY INFORMATION
Features Applications
•
Pre-Programmed Tone Generators
•
Fully Integrated DTMF Decoder/Encoder
•
SPM Generator
•
Simple Serial Control Interface
•
3.58MHz Xtal/Clock
•
V.23/Bell 202 FSK Generator
•
Digital Ringing Voltage Generator
•
Digital Line to POTS Interface
•
Subscriber Terminal Adapters
•
Wireless Local Loop
•
Computer Telephony Integration
•
Telephone/Radio Patch Systems
•
Pair Gain Systems
•
Billing/SPM Systems
Codec
DC-to-DC
µC
CALLER ID
RING
DIAL
SLIC
AnalogTelephone Port
Digital Line Circu it
CMX605
The CMX605 is an integrated telecom tone generator and DTMF encoder/decoder designed for ISDN
interfaces, Wireless Local Loop and Analog to Digital Telephone Conversion systems. The tone generator
covers an extensive range of pre-programmed tones used in analog telephone systems (POTS). Three
outputs are provided: ‘Ringing signals’, ‘In-band tones or FSK data’, and ‘12kHz/16kHz Metering pulses’.
Simple software control facilitates the interface to a wide range of commonly used µCs and SLICs, enabling a
comprehensive analog telephone line presentation.
The DTMF encoder/decoder presents the digital line interface with DTMF dialing information received from
the telephone user and generates the appropriate DTMF tones for the POTS interface. DTMF tone pairs can
be encoded along with each tone singly or with other dual tone signals, such as those used in CIDCW
systems and ‘On Hook’ signaling systems.
Other tone standards supported are: Fax and Modem ‘answer’ and ‘originate’, ITU (CCITT) ‘R1’ and ‘R2’
signals, and sufficient tones for simple melody generation. Communication to and from the host µC is
performed by a ‘C-BUS’ interface which is compatible with common serial interfaces such as: SCI, SPI, and
Microwire.
The CMX605 operates using a 2.7V to 5.5V supply and is available in the following packages: 16-pin SOIC
(CMX605D4) and 16-pin PDIP (CMX605P3).
Digital Line to POTS Interface 2 CMX605 Preliminary Information
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
CONTENTS
Section Page
1 Block Diagram................................................................................................................3
2 Signal List.......................................................................................................................4
3 External Components....................................................................................................5
4 General Description.......................................................................................................5
4.1 Xtal Osc and Clock Dividers................................................................................................ 5
4.2 Uncommitted Amplifier ........................................................................................................5
4.3 Tone/FSK Encoder and Tone Encoder ............................................................................... 6
4.4 SPM Generator.................................................................................................................... 8
4.5 Tx Signal Control................................................................................................................. 8
4.6 Tx UART.............................................................................................................................. 9
4.7 DTMF Tone Decoder........................................................................................................... 9
4.8 ‘C-BUS’ Interface............................................................................................................... 11
4.9 ‘C-BUS’ Registers.............................................................................................................. 11
5 Application ...................................................................................................................12
5.1 Telecom Tones.................................................................................................................. 13
6 Performance Specification..........................................................................................17
6.1 Electrical Performance ...................................................................................................... 17
6.1.1 Absolute Maximum Ratings.................................................................................................. 17
6.1.2 Operating Limits...................................................................................................................17
6.1.3 Operating Characteristics.....................................................................................................18
6.1.4 Timing...................................................................................................................................21
6.2 Packaging.......................................................................................................................... 22
MX-COM, Inc reserves the right to change specifications at any time and without
notice.
Digital Line to POTS Interface 3 CMX605 Preliminary Information
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
1 Block Diagram
V
DD
V
BIAS
V
BIAS
V
SS
RXIN
IN-
Tx UAR T
STATUS
and IRQ
STATUS
and IRQ
DTMF
Tone
Decoder
BUS
3.58MHz
Oscillator
PSU
SPM Generator
XTAL
XTAL/CLOCK
SERIAL
CLOCK
COMMAND
DA T A
REPLY
DA T A
CS IRQ
C-BUS Computer Serial Portm
FSK/TONES
Tx Registers
SETUP and
MODE Registers
STATUS
Register
Interrupt
Generator
ROM
Tone Encoder
Tone/FSK
Encoder
Tx Signal
Control
SPM
RING
TONEFSK
AMPOUT
Figure 1: Block Diagram
Digital Line to POTS Interface 4 CMX605 Preliminary Information
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
2 Signal List
CMX605
D4/P3
Signal Description
Pin No. Name Type
1
XTAL
output The output of the on-chip Xtal oscillator inverter.
2 XTAL/CLOCK input The input to the oscillator inverter from the Xtal circuit or
external clock source.
3 SERIAL
CLOCK
input
The ‘C-BUS’ serial clock input from the host µC.
See Section 4.8
4 COMMAND
DATA
input
The ‘C-BUS’ serial data input from the host µC.
5 REPLY DATA tri-state
A 3-state ‘C-BUS’ serial data output to the host µC. This
output is high impedance when not sending data to the host
µ
C.
6
CS
input Chip Select. The ‘C-BUS’ transfer control input provided by
the host µC.
7
IRQ
output
A ‘wire-ORable’ output for connection to a host µC Interrupt
Request input. This output is pulled down to V
SS
when active
and is high impedance when inactive. An external pull-up
resistor is required.
8VSSpower The negative supply rail (ground).
9 TONEFSK output The sinewave output of the Tones and FSK signal
generators.
10 SPM The sinewave output of the SPM signal generator.
11 V
BIAS
output An internally generated bias voltage of VDD/2, except when
the device has been reset, V
BIAS
will discharge to VSS. It
should be bypassed to V
SS
by a capacitor mounted close to
the device pins.
12 RXIN input The input to the DTMF decoder, internally biased at VDD/2. It
should be AC coupled.
13 IN- input The inverting input to the uncommitted amplifier.
14 AMPOUT output The output of the uncommitted amplifier.
15 RING output The squarewave output of the Ringing Signal generator.
16 V
DD
power The positive supply rail. Levels and thresholds within the
device are proportional to this voltage. It should be bypassed
to V
SS
by a capacitor mounted close to the device pins.
This device is capable of detecting and decoding small amplitude signals. To achieve this, VDD and V
BIAS
decoupling and protection of the receive path from extraneous in-band signals are very important. It is
recommended that the printed circuit board is laid out with a ground plane in the CMX605 area to provide a
low impedance connection between the V
SS
pin and the VDD and V
BIAS
bypass capacitors.
Table 1: Signal List
Digital Line to POTS Interface 5 CMX605 Preliminary Information
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
3 External Components
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
XTAL/CLOCK
XTAL
IRQ
SERIAL CLOCK
REPLY DATA
COMMAND DATA
CS
RING
AMPOUT
IN-
SPM
V
BIAS
RXIN
TONEFSK
X1
R1
C1
C2
C5
C3
C4
V
SS
V
DD
V
DD
V
DD
CMX605
Figure 2: Recommended External Components
R1 100k
: C1, C2 18pF
C3 0.1µF
X1 3.579545 MHz C4, C5 1.0µF
Table 2: Recommended External Components
Recommended External Component Notes:
1. Resistors ±5%, capacitors ±10% unless otherwise stated.
2. For best results, a crystal oscillator design should drive the clock inverter input with signal levels of at
least 40% of V
DD
, peak to peak. Tuning fork crystals generally cannot meet this requirement. To obtain
crystal oscillator design assistance, please consult your crystal manufacturer.
4 General Description
The CMX605 is a telecom tone generator and DTMF tone encoder/decoder. It has separate output ports for
the three different classes of signals encoded. These include Ringing signal, In-band tones or FSK data at
1200bps and High frequency metering pulses (SPM tones). It has a transmit level attenuator for In-band
tones or FSK data and an envelope control for SPM tones. It also has an uncommitted amplifier and uses the
industry standard 3.58MHz Xtal for its oscillator. These functions are controlled over a ‘C-BUS‘ serial µC
interface, which also carries the transmit FSK data and the DTMF decoded data.
The CMX605 should initially be reset by issuing a ‘C-BUS’ RESET command. Individual functions may be
disabled or enabled by the use of bits 5, 6 and 7 in the SETUP Register. See Section 4.9. Approximately
50ms should be allowed for the Tx dc level to settle at V
BIAS
before enabling the Tx functions (set bit 6 of the
MODE Register to ‘1’) after the CMX605 has been reset.
4.1 Xtal Osc and Clock Dividers
Frequency and timing accuracy of the CMX605 is determined by a 3.579545MHz clock present at the
XTAL/CLOCK pin. This may be generated by the on-chip oscillator inverter using the external components
C1, C2 and X1 of Figure 2, or may be supplied from an external source to the XTAL/CLOCK input. If the clock
is supplied from an external source, C1, C2 and X1 should not be fitted.
If the clock is provided by an external source which is not always running, then the CMX605 should be reset
when the clock is not available. Resetting the CMX605 will also turn off the on-chip oscillator. Failure to reset
the device may cause a rise in the supply current drawn by the CMX605.
4.2 Uncommitted Amplifier
This amplifier, with suitable external components, can be used either for adjusting the received signal to the
correct amplitude for the DTMF decoder or for adjusting the transmit signal level (for the line hybrid).
Digital Line to POTS Interface 6 CMX605 Preliminary Information
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
4.3 Tone/FSK Encoder and Tone Encoder
When bit 5 of the MODE Register is set to ‘1’ then these blocks generate FSK signals as determined by bit 0
of the SETUP Register and the Tx data bits from the UART block, as shown in Table 3.
SETUP Register
Bit 0
Tone/FSK Generator FSK Signal Frequency
‘0’ (Space)
FSK Signal Frequency
‘1’ (Mark)
0 V23 1200bps FSK 2100Hz 1300Hz
1 Bell 202 1200bps FSK 2200Hz 1200Hz
Table 3: Tone/FSK Encoder and Tone Decoder
When bit 5 of the MODE Register is set to ‘0’, these blocks generate single or dual tones from the range
shown in Table 4, Table 5, Table 6, and Table 7. Bit 6 of the MODE Register is then used to enable or
disable the block’s output to the Tx Signal Control, RING, and ToneFSK outputs. There are four tone fields
addressed by bits 0 and 1 of the MODE Register.
TX TONES Register Bits 4-7 TX TONES Register Bits 0-3
D7 D6 D5 D4
Frequency
(Hz)
D3 D2 D1 D0
Frequency
(Hz)
0 0 0 0 0 = OFF 0 0 0 0 0 = OFF
0 0 0 1 252.4 0 0 0 1 * 17.1
0 0 1 0 268.7 0 0 1 0 * 20.5
0 0 1 1 285.3 0 0 1 1 * 24.9
0 1 0 0 315.5 0 1 0 0 * 34.1
0 1 0 1 330.5 0 1 0 1 * 41.0
0 1 1 0 375.2 0 1 1 0 * 51.2
0 1 1 1 404.3 0 1 1 1 1 0 0 0 468.0 1 0 0 0 262.9
1 0 0 1 495.8 1 0 0 1 293.6
1 0 1 0 520.6 1 0 1 0 348.2
1 0 1 1 548.0 1 0 1 1 392.6
1 1 0 0 562.8 1 1 0 0 1600
1 1 0 1 578.4 1 1 0 1 1633
1 1 1 0 595.0 1 1 1 0 1827
1 1 1 1 612.5 1 1 1 1 587.2
Table 4: Tone Field 0, MODE Register bit 1 and bit 0 = ‘0’ and ‘0’ respectively.
NOTE: * These outputs are routed to the RING digital output instead of the TONEFSK output. Any single
tone output level at TONEFSK output is 0dBm.
Digital Line to POTS Interface 7 CMX605 Preliminary Information
1999 MX-COM, Inc. www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054 Doc. # 20480195.003
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
TX TONES Register Bits 4-7 TX TONES Register Bits 0-3
D7 D6 D5 D4
Frequency
(Hz)
D3 D2 D1 D0
Frequency
(Hz)
0 0 0 0 0 = OFF 0 0 0 0 0 = OFF
0 0 0 1 120 0 0 0 1 330
0 0 1 0 150 0 0 1 0 416
0 0 1 1 154 0 0 1 1 420
0 1 0 0 250 0 1 0 0 425
0 1 0 1 300 0 1 0 1 433
0 1 1 0 350 0 1 1 0 440
0 1 1 1 360 0 1 1 1 450
1 0 0 0 367 1 0 0 0 460
1 0 0 1 375 1 0 0 1 480
1 0 1 0 380 1 0 1 0 500
1 0 1 1 383 1 0 1 1 600
1 1 0 0 400 1 1 0 0 620
1 1 0 1 450 1 1 0 1 720
1 1 1 0 475 1 1 1 0 930
1 1 1 1 480 1 1 1 1 -
Table 5: Tone Field 1, MODE Register bit 1 and bit 0 = ‘0’ and ‘1’ respectively
TX TONES Register Bits 4-7 TX TONES Register Bits 0-3
D7 D6 D5 D4
Frequency
(Hz)
D3 D2 D1 D0
Frequency
(Hz)
0 0 0 0 0 = OFF 0 0 0 0 0 = OFF
0 0 0 1 700 0 0 0 1 700
0 0 1 0 900 0 0 1 0 900
0 0 1 1 1100 0 0 1 1 1100
0 1 0 0 1300 0 1 0 0 1300
0 1 0 1 1500 0 1 0 1 1500
0 1 1 0 1700 0 1 1 0 1700
0111 - 0111 1 0 0 0 950 1 0 0 0 2100
1 0 0 1 1400 1 0 0 1 2225
1 0 1 0 1800 1 0 1 0 1 0 1 1 2130 1 0 1 1 2750
1 1 0 0 697 1 1 0 0 1209
1 1 0 1 770 1 1 0 1 1336
1 1 1 0 852 1 1 1 0 1477
1 1 1 1 941 1 1 1 1 1633
Table 6: Tone Field 2, MODE Register bit 1 and bit 0 = ‘1’ and ‘0’ respectively
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