CMX624D2 Consumer Microcircuits Limited, CMX624D2 Datasheet

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CMX624D2

Manufacturer Part Number
CMX624D2
Description
Manufacturer
Consumer Microcircuits Limited
Datasheet

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Part Number:
CMX624D2
Manufacturer:
CML
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20 000
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Part Number:
CMX624D2
Quantity:
5 220
Features
1.1
The CMX624 V.23 / Bell 202 modem is intended for use in any telephone based information and telemetry
system with low power requirements. Using FSK signalling, fast call set-up times and robust error resistant
transmission can be implemented by efficient low power circuits. The circuit can operate at 1200bps full
duplex over a 4-wire circuit or 1200 bps plus low speed data over a 2-wire circuit. Flexible line driver and
receive hybrid circuitry are integrated on chip requiring only passive external components to build a 2- or 4-
wire interface. A low impedance pull down output is provided for a hook relay.
Control of the device is via a simple high speed serial bus; this allows easy interfacing to a host µController.
The data transmitted and received by the modem is also transferred over the same high speed serial bus. On-
chip programmable Tx and Rx UARTs allow asynchronous data to be simultaneously encoded and decoded.
Either UART may be disabled to allow 8-bit raw data to be received or transmitted. Any repetitive 8-bit data
pattern can be sent without the controller having to reload data every 8 bits. All 16 DTMF combinations are
available along with a single tone 'melody' mode. The ringing, 2100Hz, call progress and data detectors
included on the CMX624 make the set-up of a telephone call a simple matter for the host µController.
In many data collection and telemetry systems low power consumption is important. The CMX624 features a
'Zero Power' standby mode. Whilst in standby the ring detector continues to operate and will supply the host
µController with an interrupt when line reversal or ringing is detected. The CMX624 can operate on a supply
voltage between 3.0V and 5.5V across the full temperature range of -40°C to +85°C.
The CMX624 is pin compatible with the CMX644A V22 and Bell 212A modem also from CML.
2001 Consumer Microcircuits Limited
V.23 / Bell 202 Compatible Modem
Integrated DTMF Encoder
Call Progress Tone Detection
Line Reversal and Ring Detector
Low Power Operation (2.7V)
Part of the CMX6x4 Modem Series
D/624/6 January 2001
Brief Description
Applications
Telephone Telemetry Systems
Remote Utility Meter Reading
Security Systems/Cash Terminals
Industrial Control Systems
Pay-Phones
Cable TV Set-Top Boxes
V.23/Bell 202 Modem
CMX624
Provisional Information

Related parts for CMX624D2

CMX624D2 Summary of contents

Page 1

... The CMX624 can operate on a supply voltage between 3.0V and 5.5V across the full temperature range of -40°C to +85°C. The CMX624 is pin compatible with the CMX644A V22 and Bell 212A modem also from CML. 2001 Consumer Microcircuits Limited CMX624 V.23/Bell 202 Modem ...

Page 2

... Application Notes....................................................................................14 1.6.1 Line Interface..............................................................................15 1.6.2 Ring Detector Interface .............................................................17 1.7 Performance Specification.....................................................................19 1.7.1 Electrical Performance..............................................................19 1.7.2 Packaging....................................................................................24 Note: This product is in development: Changes and additions will be made to this specification. Items marked TBD or left blank will be included in later issues. 2001 Consumer Microcircuits Limited CONTENTS 2 CMX624 Page D/624/6 ...

Page 3

... V23 / Bell 202 Modem 1.2 Block Diagram 2001 Consumer Microcircuits Limited Figure 1 Block Diagram 3 CMX624 D/624/6 ...

Page 4

... BIAS 14 RLYDRV 15 RXP 2001 Consumer Microcircuits Limited Description Type O/P The output of the on-chip Xtal oscillator inverter. I/P The input to the oscillator inverter from the Xtal circuit or external clock source. I/P The ‘C-BUS’ serial clock input from the C. See Section 1.5.11 I/P The ‘ ...

Page 5

... This device is capable of detecting and decoding small amplitude signals. To achieve this V decoupling and protecting the receive path from extraneous in-band signals are very important recommended that the printed circuit board is laid out with a ground plane in the CMX624 area to provide a low impedance connection between the V 2001 Consumer Microcircuits Limited Description Type I/P The inverting input to the Rx input amplifier ...

Page 6

... The on-chip oscillator is turned off in the 'Zero-Power' mode. If the clock is provided by an external source which is not always running, then the 'Zero-Power' mode must be set when the clock is not available. Failure to observe this rule may cause a rise in the supply current drawn by CMX624. 2001 Consumer Microcircuits Limited 100k 3.579545MHz 6 ...

Page 7

... Figure 3a Rx Frequency Responses with Line Interface Figure 3b ETS 300 114 Test Line 1 Characteristics (Normalised) 2001 Consumer Microcircuits Limited 1000 Hz see section 1.6.1 (equaliser disabled) 500 1000 1500 2000 2500 Hz 7 1200bps 75/150 bps Call Progress ...

Page 8

... V.23 mode (bit 7 of SETUP register = ‘0’): FSK MODE Reg Bit 1 Bit 2001 Consumer Microcircuits Limited FSK MODE Reg Bit See Section 1.7.1 for definitions of Teon and Teoff Figure 4 Rx Energy Detector Timing FSK / DTMF Modulator block output (Bit TONES = ‘ ...

Page 9

... Section 1.6.1 for a nominal FSK transmit level of -9dBm, DTMF tone levels of -8dBm and -6dBm, then the out of band energy sent to the line will be within the limits shown in Figure 5 for both FSK and DTMF signals. 2001 Consumer Microcircuits Limited FSK / DTMF Modulator block output (Bit TONES = ‘ ...

Page 10

... Register. Any ‘0’ to ‘1’ or ‘1’ to ‘0’ change on this line will also set the ‘Ring Detect Change’ bit (5) of the FLAGS Register. If this block is not used, then the RD and RT pins should be connected to V bit (5) of the IRQ MASK Register set to ‘0’. 2001 Consumer Microcircuits Limited Bell 202 V23 100 1000 ...

Page 11

... FLAGS Register being set to ‘1’ and if the ‘Tx Async’ mode of operation had been selected then a continuous Mark (‘1’) signal will then be transmitted until a new value is loaded into TX DATA, whereas in ‘Tx Sync’ mode the byte already in the TX DATA Register will be re-transmitted. 2001 Consumer Microcircuits Limited Figure 6a Transmit UART Function (Async) 11 ...

Page 12

... RX DATA Register. If the previous contents of the RX DATA Register had not been read out over the ‘C- BUS’ before the new value is loaded from the UART then bit 3 (Rx Data Overflow) of the FLAGS Register will also be set to ‘1’. 2001 Consumer Microcircuits Limited Figure 6b Receive UART Function (Async) 12 ...

Page 13

... SCI, SPI and Microwire, and may also be easily implemented with general purpose µC I/O pins controlled by a simple software routine. See Figure 10 for detailed ‘C-BUS’ timing requirements. 2001 Consumer Microcircuits Limited Figure 7 ‘C-BUS’ Transactions 13 ...

Page 14

... IRQ MASK Register (bit 4) is normally set to ‘0’ - but can be set to ‘1’ to enable interrupts on the IRQN output. In the latter case, IRQN will be continuously pulled to ‘0’ whilst Rx Energy or 2100Hz are present. This may be useful for device evaluation purposes. 1.6 Application Notes 2001 Consumer Microcircuits Limited Command Data Byte Bits ...

Page 15

... Assuming transformer loss of about 1dB, R11 should be 91k Note relay circuit, ac and dc loads and line protection not shown for clarity. R10 600 R11 See text R12 100k 2001 Consumer Microcircuits Limited 4-wire line. The line terminations are provided by R10 at 5.0V, or 130k at 3.0V. R13 See text R14 100k R15 600 Resistors 1%, capacitors 20% ...

Page 16

... The values of R11 and R13 should be calculated in the same way as for the 4-wire interface circuit of Figure 8a. 2001 Consumer Microcircuits Limited and is also affected by the setting of the Tx o/p level control bit DD ...

Page 17

... Vthi is the high-going threshold voltage of the Schmitt trigger A (see Section 1.7.1). With R20-22 all 470k as Figure 9, then setting R23 to 68k 40Vrms and above for V over the range 3.0 to 5.5V. DD R20, 21, 22 R23 R24 2001 Consumer Microcircuits Limited C20, 21 470k See text C22 470k D1-4 Resistors 1%, capacitors 20% Figure 9 Ring Signal Detector Interface Circuit ...

Page 18

... Note that the circuit will also respond to a telephone line voltage reversal. If necessary the C can distinguish between a Ring signal and a line voltage reversal by measuring the time that bit 6 of the FLAGS Register (Ring Detect) is high. 2001 Consumer Microcircuits Limited towards V can be derived from the formula ...

Page 19

... Storage Temperature Operating Temperature 1.7.1.2 Operating Limits Correct operation of the device outside these limits is not implied. Supply ( Operating Temperature Xtal Frequency Notes Xtal frequency of 3.579545MHz ±0.1% is required for correct operation. 2001 Consumer Microcircuits Limited pins SS Notes 1 19 Min. Max. Unit -0.3 7 ...

Page 20

... Tx 150bits/sec (Bell 202 mode) Baud Rate (set by UART and Xtal frequency) Mark (Logical 1) Frequency Space (Logical 0) Frequency Notes 5.0V, Tx o/p level control bit set to ‘1’; load resistance greater than 40k . DD 2001 Consumer Microcircuits Limited = 3.0V to 5.5V at Tamb = -40 to +85°C, DD 0.1%, 0dBm corresponds to 775mVrms. Notes 5.0V ...

Page 21

... Decode’ Frequency Range ‘Will Not Decode’ Frequency Range ‘Off’ to ‘On’ time ‘On’ to ‘Off’ time Notes: 9. 2100Hz detection requires a signal within the amplitude range given in the Rx Energy Detector section. 2001 Consumer Microcircuits Limited Notes 4 Notes 5 Notes 6 ...

Page 22

... Reply Data Hold time RDH Note: These timings are for the latest version of the ‘C-BUS’ as embodied in the CMX624, and allow faster transfers than the original ‘C-BUS’ timings given in CML Publication D/800/Sys/3 July 1994. 2001 Consumer Microcircuits Limited Notes ...

Page 23

... V23 / Bell 202 Modem 3.5 3 2.5 2 Vin 1.5 1 0.5 0 Figure 11 Typical Schmitt Trigger Input Voltage Thresholds vs. V 2001 Consumer Microcircuits Limited Figure 10 ‘C-BUS’ Timing 2.5 3 3.5 4 Vdd 23 Vthi Vtlo 4.5 5 5.5 DD CMX624 D/624/6 ...

Page 24

... V23 / Bell 202 Modem 1.7.2 Packaging Figure 12a 24-pin SOIC (D2) Mechanical Outline: Order as part no. CMX624D2 Figure 12b 24-pin SSOP (D5) Mechanical Outline: Order as part no. CMX624D5 2001 Consumer Microcircuits Limited 24 CMX624 D/624/6 ...

Page 25

V23 / Bell 202 Modem Figure 12c 24-pin DIL (P4) Mechanical Outline: Order as part no. CMX624P4 Handling precautions: This product includes input protection, however, precautions should be taken to prevent device damage from electro-static discharge. CML does not assume ...

Page 26

... CML Microcircuits Product Prefix Codes Until the latter part of 1996, the differentiator between products manufactured and sold from MXCOM, Inc. and Consumer Microcircuits Limited were denoted by the prefixes MX and FX respectively. These products use the same silicon etc. and today still carry the same prefixes. ...

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