INNOVATIONS INV/TwoWay/823/1 August 2003 CMX823 Programmable Paging-Tone Decoder An Ultra-Low-Power Audio Tone Decoder for Paging Operations in Low Signal-to-Noise Environments www.cmlmicro.com The CMX823 can decode any combination of up to 32 different in-band tones from a user-programmed on-chip list, received in any order. With a decode frequency range of 280Hz to 3500Hz and a Signal-to-Noise Ratio of -4dB, this ultra low-power product is ideal for the majority of paging and selective calling applications, offering reliability in even the most hostile of signalling environments. Total Versatility is the thinking behind the design of this multiple-format tone-decoder as, under serial data control, this product has the selectable option of two measurement modes (Fast and Slow) to efficiently facilitate various tone format periods, operating conditions and host µController requirements. Decode Speed: Employing two user-defined on-chip lists, the CMX823 can store up to 32 tones per list with the ability to rapidly switch between lists to facilitate different toneset formats. Each list can be further subdivided to allow even faster tone recognition. Tone lists can be dynamically uploaded by the host µC if required. Applications n Two-Tone and Multi-Tone Tone Pagers n Voice Pager Switching and Signalling n Selective Calling (Selcall) n Revertive Paging n Wireless Local Loop Signalling n Audio Tone Signalling The CML Advantage n Decodes from a List of 32 Tones n Two Separate 32-Tone Lists Available n All Tone Frequencies are User Defined n ‘Fast Switch’ Between Tone Lists n Superior Signal-to-Noise (-4dB) Performance n Selectable ‘Fast’ and ‘Slow’ Measurement Modes Facilitate All Toneset Formats n n n n Integral NOTONE Timer Versatile Status and Interrupt Indications Control and Data via C-BUS Serial Interface Low-Power 2.7 Volt Operation with ‘Zero-Power’ Mode n 2.7 to 5.5 Volt Operating Voltage Range n Compact 16-Pin TSSOP and DIL Packaging Decodes Signals Through The Noise Floor! CML Microcircuits COMMUNICATION SEMICONDUCTORS Application Specific Standard Products for Two-Way Radio, Wireline Telecoms and Wireless Data Two-Way Radio The CMX823 Simple, Versatile, Efficient and Fast Specification Supply Voltage Range 2.7V to 5.5V 0.75mA 1.5mA Zero Power Current VDD = 2.7V 1.0µA 280Hz to 3500Hz Decode Signal-to-Noise Ratio -4dB Tone Storage Capacity 2 Sets of 32 Tones Fast and Slow XTAL AND CLOCKS XTAL/ CLOCK IRQN OPAMP OUT SEQUENCER AND COMPARATOR VSS TONE LIST 1 AND TONE LIST 2 C-BUS INTERFACE AND CONTROL LOGIC REPLY DATA CSN COMMAND DATA SERIAL CLOCK 28ms Slow Mode 33ms Slow Mode FREQUENCY ASSESSMENT AND MEASUREMENT VDD /2 VDD Response Time Fast Mode De-response Time Fast Mode XTALN 1.0µA Tone Frequency Range Tone Measurement Modes Input Gain DIGITAL FILTER Operating Current (typ.) VDD = 2.7V VDD = 5.0V VDD = 5.0V SIGNAL IN The CMX823 Functional Block Diagram 46ms 79ms Input Gain Decode Bandwidth Range ±0.1% to ±3.1% Control and Data C-BUS Serial Interface Package Styles E4 16-pin TSSOP Communication with, and control of, the CMX823 is via the C-BUS hardware and software serial interface. P3 16-pin DIL Frequency Stability The component-adjustable op-amp input stage is available to adjust the received signal to the correct amplitude for the decoder process. Control and Data Decode frequency stability is ensured by the use on an on-chip ‘clock’ oscillator requiring an input from an external (3.58MHz) Xtal or clock source. Using this common ‘telecom’ Xtal frequency will reduce the external circuitry requirement. Selectable decode bandwidth settings allow the reception of tones from less stable sources. Power Requirements With a voltage range of 2.7V to 5.5V, a low operating power requirement and a ‘zero-power’ mode, the CMX823 is configurable for use in all types of tone communication paging products with many types of host µC. Tone Operations Tone Detection SIGNAL IN Decoder Input Level Setting FREQUENCY ASSESSMENT AND MEASUREMENT DIGITAL FILTER When the CMX823 detects the start of a valid in-band tone (a tone in the selected userdefined tone list) it generates an interrupt and VDD /2 reports, via its on-chip C-BUS interface, which tone was detected. At the end of that tone it OPAMP OUT produces another interrupt and reports NOTONE detected. This information is available, in several forms, to enable the host µC to measure and interpret the tone and gap lengths according to the toneset requirements. These actions take place for each response/de-response action no matter what the length of the tone sequence. Tone parameters are stored in one or both of the ‘tone lists’. The tone decode parameters for the selected list and group are sequentially retrieved and matched with those of the received signal to find a tone decode. Tone decode status changes are flagged in the Status Register. Tone Parameters The parameters for decoding each tone in the tone list are stored separately. Two selectable lists are available; only one is accessed at any one time. List contents are preloaded by the host and are maintained during ‘table-switching’ and ‘Zero-Power’ mode powersave operations. Tone decode parameters can be designated, within a tone list, to either one or both tone-groups; these groups can be used to represent the first or second tones in a tone sequence. Upon reception and measurement of an input tone, the tone decode parameters of the selected group are sequentially retrieved from the selected list and compared with the decoded parameters. A match will result in the generation of an interrupt and the decoded tone’s status and parameters. SERIAL CLOCK SEQUENCER AND COMPARATOR CSN C-BUS INTERFACE AND CONTROL LOGIC Load Tone Parameters Tone List 1 Location Tone Group 1 2 IRQN COMMAND DATA Tone List 2 Tone Parameters Tone Group 1 2 Location 0 1 2 3 . . . 30 31 REPLY DATA Tone Parameters 0 1 2 3 . . . 30 31 Decoded Tone Location Register Tone Position in Selected List Decoded Tone Parameters Register Status Register Tone Group Tone Change Tone Parameters (as loaded) Decode Status Change Tone Decode Unlisted Tone tone and decode indications and parameters available to the host µC Tone Lists, Indications and Parameters Tone Lists and Groups Decode Tone Bandwidths The CMX823 contains two ‘tone lists’ (1 and 2) each capable of storing parameters for thirty-two user-designated tones. Each list can be further sub-divided into two ‘tone groups’. Each ‘tone list’ is intended for use with a single RF channel allowing a fast list-switch (between 1 and 2) when changing RF channels. These bandwidth settings, variable between ±0.1% to ±3.1%, are available for compliance to all radio signalling and toneset specifications. These settings can be also used to ‘tune’ the decode process by preventing false decoding due to ‘bandwidth overlap’ and to enable the accurate reception of unstable Rx signals. Tone decode parameters can belong to either or both ‘tone groups’; a feature which may be used to represent the first and second tones in a tone sequence; this will further speed-up the decoding process. Decode Reporting To enable further efficiency and speed in tone decode reporting to the host, the Status Register indicates, separately, the various decode actions. Fast and Slow Measurement Modes Tone Change: These two modes of response/de-response time measurement are available to allow the most efficient use of µC time and to facilitate the widest range of paging tone-set format requirements. Fast mode is intended for 5/6-tone paging tonesets and Slow mode for 2-tone paging tonesets where slower response times are acceptable. For bespoke systems, these modes can be employed for the reduction of false decodes. Decode Status Change: Any change in the decoder operation Unlisted Tone: Whenever a ‘listed’ tone-decode changes The decoding of any tone in the valid frequency range but not in the selected list. NOTONE: The loss of a valid tone. An automatic N OTONE timer period is instigated. Tone List: The list that was selected when the match was found. Other Recent CML PMR IC Products ● CMX649 Adaptive Delta Modulation (ADM) Codec ● CMX881 Baseband Processor for PMR and Trunked Radios ● CMX882 Baseband Processor with GPS Data Signalling for FRS, GMRS, MURS and PMR446 ‘Leisure’ Radios ● EV8810 For CMX881, CMX882 and CMX883 Evaluation ● CMX981 Advanced Digital-Radio Baseband Processor Member Companies CML Microcircuits (UK)Ltd COMMUNICATION SEMICONDUCTORS Oval Park, Langford, MALDON, Essex CM9 6WG, England Tel: +44 (0)1621 875500 Fax: +44 (0)1621 875600 [email protected] www.cmlmicro.com CML Microcircuits (USA) Inc. COMMUNICATION SEMICONDUCTORS Decodes Signals Through The Noise Floor! 4800 Bethania Station Road, Winston-Salem, NC 27105, USA Tel: +1 336 744 5050, 800 638 5577 Fax: +1 336 744 5054 [email protected] www.cmlmicro.com Packages CMX823E4 CMX823P3 CML Microcircuits (Singapore)PteLtd -40º to +85ºC 16-pin plastic TSSOP 16-pin plastic DIL COMMUNICATION SEMICONDUCTORS Singapore No. 2 Kallang Pudding Road, #09 - 05/06 Mactech Industrial Building, Singapore 349307 Tel: +65 67450426 Fax: +65 67452917 [email protected] www.cmlmicro.com Shanghai No. 218, Tian Mu Road West, Tower 1, Unit 1008, Shanghai Kerry Everbright City, Zhabei, Shanghai 200070, China Tel: +86 21 63174107 and +86 21 63178916 Fax: +86 21 63170243 [email protected] www.cmlmicro.com Information www.cmlmicro.com/products/twoway/CMX823.htm © 2003 CML Microcircuits