CMX866 CML Microcircuits V.22 bis Modem COMMUNICATION SEMICONDUCTORS with AT Commands D/866/5 May 2008 Provisional Issue Features Applications • V.22 bis, V.22 and Bell 212A QAM/DPSK • Telephone Telemetry Systems • V.23, Bell 202, V.21 and Bell 103 FSK • Remote Utility Meter Reading • Integral AT Command Set with 'Fast Connect' • Security Systems • V.23 and Bell 202 'Fast Turnaround' • Industrial Control Systems • Support for Type 1 Caller Line Identification • Electronic Cash Terminals / ATMs • DTMF/Programmable Tones: Transmit and Receive • Pay-Phones • 'Zero-Power' and Powersave Standby Modes • Cable TV Set-Top Boxes • Low Power Operation • EPOS Terminals 1.1 Brief Description The CMX866 is a multi-standard modem for use in telephone based information and telemetry systems. Control of the device is via AT commands over a simple 9600b/s serial interface, compatible with most types of host µController. An RS232 compatible interface can be created by the addition of a Level Converter. The data transmitted and received by the modem is also transferred over the same serial interface. The on-chip µController interprets these AT commands and controls an internal DSP, which provides the modem and anciliary functions such as Ring Detection, Call Progress Detection, Hook Switch control and DTMF autodialling. User-specific DSP functions are also available via the AT command set. Hardware support is provided for V.23 and Bell 202 Fast Turnaround and for rapid return to AT Command mode. A Fast Connect mode has been implemented to reduce modem connection time. Flexible line driver and receive hybrid circuits are integrated on chip, requiring only passive external components to build a 2 or 4-wire line interface. Complete examples of 2-wire line interfaces to an external host µC and to an RS232 interface, including the additional components required for Type 1 CLI, are provided. The device features a Hook Switch relay drive output and a Ring Detector circuit that remain operational when the CMX866 is in 'Zero-Power' or Powersave mode, providing an interrupt which can be used to wake up an external host µC, as well as the CMX866, when line voltage reversal or ringing is detected. The device is also able to detect off-hook parallel phones by monitoring voice activity on the line. The CMX866 takes 5mA (typ.) from a single 2.7–5.5V supply and comes in 28-pin SSOP/SOIC packages. © 2008 CML Microsystems Plc V.22 bis Modem with AT Commands CMX866 CONTENTS Section Page 1.1 Brief Description .................................................................................................1 1.2 Block Diagram.....................................................................................................3 1.3 Signal List ............................................................................................................4 1.4 External Components.........................................................................................6 1.4.1 Ring Detector Interface .........................................................................8 1.4.2 Line Interface..........................................................................................9 1.4.3 Serial Interface .....................................................................................11 1.4.4 RESETN pin ..........................................................................................12 1.5 General Description..........................................................................................13 1.5.1 Internal Structure .................................................................................13 1.5.2 Operating States and Data Flow.........................................................14 1.5.3 Functional Description........................................................................16 1.5.4 AT Command and Register Set ..........................................................17 1.5.4.1 AT Command and S-Register Summary...............................17 1.5.4.2 General Description of AT Commands.................................19 1.5.4.3 AT Commands in Detail..........................................................20 1.5.4.4 Extended AT Commands .......................................................23 1.5.4.5 S-Registers ..............................................................................26 1.5.4.6 Result Codes ...........................................................................30 1.5.5 Tx USART..............................................................................................30 1.5.6 FSK and QAM/DPSK Modulators .......................................................32 1.5.7 Tx Filter and Equaliser ........................................................................33 1.5.8 DTMF/Tone Generator .........................................................................33 1.5.9 Tx Level Control and Output Buffer...................................................33 1.5.10 Rx DTMF/Tones Detectors ..................................................................34 1.5.11 Rx Modem Filterering and Demodulation..........................................35 1.5.12 Rx Modem Pattern Detectors and Descrambler ...............................36 1.5.13 Rx Data Register and USART .............................................................36 1.6 Application Notes .............................................................................................38 1.6.1 Hardware Interface ..............................................................................38 1.6.2 Calling Modem AT Commands...........................................................43 1.6.3 Answering Modem AT Commands ....................................................43 1.6.4 RS232 Transaction Sequence ............................................................44 1.7 Performance Specification...............................................................................45 1.7.1 Electrical Performance........................................................................45 1.7.1.1 Absolute Maximum Ratings...................................................45 1.7.1.2 Operating Limits .....................................................................45 1.7.1.3 Operating Characteristics......................................................46 1.7.2 Packaging .............................................................................................52 It is always recommended that you check for the latest product datasheet version from the Datasheets page of the CML website: [www.cmlmicro.com]. © 2008 CML Microsystems Plc 2 D/866/5 V.22 bis Modem with AT Commands CMX866 1.2 Block Diagram Figure 1 Block Diagram © 2008 CML Microsystems Plc 3 D/866/5 V.22 bis Modem with AT Commands CMX866 1.3 Signal List CMX866 Signal Description D1/D6 Pin No. Name Type 1 XTALN O/P The output of the on-chip Xtal oscillator inverter. 2 XTAL/CLOCK I/P The input to the oscillator inverter from the Xtal circuit or external clock source. 3 N/C ~ Reserved for future use. Connect this pin to DVSS. 4 N/C ~ Reserved for future use. Connect this pin to DVSS. 5 RDRVN O/P Relay drive output, low resistance pull down to DVSS when active and medium resistance pull up to DVDD when inactive. 6 DVSS Power The negative supply rail for the digital on-chip blocks. 7 RD I/P Schmitt trigger input to the Ring signal detector. Connect to DVSS if Ring Detector not used. 8 RT BI Open drain output and Schmitt trigger input forming part of the Ring signal detector. Connect to DVDD if Ring Detector not used. 9 RESETN I/P Schmitt trigger input to an active-low reset pin. Connect to DVDD if no external reset signal used 10 RXAFB O/P The output of the Rx Input Amplifier. 11 RXBN I/P An alternative, switched inverting input to the Rx Input Amplifier, used to increase the amplifier gain for the detection of on-hook signals. If this input is not required, leave the pin disconnected. 12 RXAN I/P The inverting input to the Rx Input Amplifier 13 RXA I/P The non-inverting input to the Rx Input Amplifier. If this pin is to be connected to VBIAS then it should also be decoupled to AVSS locally. 14 AVSS Power The negative supply rail for the analogue on- chip blocks. 15 VBIAS O/P Internally generated bias voltage of approximately AVDD /2, except when the device is in Powersave or 'Zero-Power' modes, when VBIAS will discharge to AVSS. This pin should be decoupled to AVSS by a capacitor mounted close to the device pins. 16 TXAN O/P The inverted output of the Tx Output Buffer. 17 TXA O/P The non-inverted output of the Tx Output Buffer. © 2008 CML Microsystems Plc 4 D/866/5 V.22 bis Modem with AT Commands CMX866 CMX866 Signal Description D1/D6 18 AVDD Power The positive supply rail for the analogue on-chip blocks. Levels and thresholds within the device are proportional to this voltage. 19 DCDN O/P The inverted DCD signal used for an RS232 interface with a Level Converter. 20 DSRN O/P The inverted DSR signal used for an RS232 interface with a Level Converter. 21 CTSN O/P The inverted CTS signal used for an RS232 interface with a Level Converter. 22 DTRN I/P The inverted DTR signal used for an RS232 interface with a Level Converter. 23 RTSN I/P The inverted RTS signal used for an RS232 interface with a Level Converter. 24 TXD I/P The non-inverted TD signal used for an RS232 interface with a Level Converter. This pin accepts data from the external host µC for transmission over the phone line. 25 RXD O/P The non-inverted RD signal used for an RS232 interface with a Level Converter. This pin sends data to the external host