M-8880 CLARE [Clare, Inc.], M-8880 Datasheet
M-8880
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M-8880 Summary of contents
Page 1
... PBX systems, computer systems, fax machines, pay telephones, credit card verification The M-8880 is a complete DTMF Transmitter/Receiver that fea- tures adjustable guard time, automatic tone burst mode, call progress mode, and a fully compatible 6500/6800 microproces- sor interface. The receiver portion is based on the industry stan- ...
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... GT output acts to reset the external steering time-constant; its state is a funciton of ESt and the voltage on St. V Positive power supply input. DD 40-406-00012, Rev. G M-8880 Figure 4 Differential Input Configuration A decoder employs digital counting techniques to determine the frequencies of the incoming tones, and to verify that they corre- spond to standard DTMF frequencies. A complex averaging al- gorithm protects against tone simulation by extraneous signals (such as voice), while tolerating small deviations in frequency ...
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... The contents of the output latch are updated on an active de- layed steering transition. This data is presented to the 4-bit bidirectional data bus when the receive data register is read. 40-406-00012, Rev. G M-8880 The steering circuit works in reverse to validate the interdigit pause between signals. Thus, as well as rejecting signals too reaches the threshold short to be considered valid, the receiver will tolerate signal in- terruptions (dropout) too short to be considered a valid pause ...
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... Figure 7 Call Progress Response DTMF Generator The DTMF transmitter used in the M-8880 is capable of generat- ing all 16 standard DTMF tone pairs with low distortion and high accuracy. All frequencies are derived from an external 3.58 MHz crystal. The sinusoidal waveforms for the individual tones are digitally synthesized using row and column programmable dividers and switched capacitor digital-to-analog converters ...
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... DTMF Clock Circuit The internal clock circuit is completed with the addition of a stan- dard 3.579545 MHz television color burst crystal. A number of M-8880 devices can be connected as shown in Figure 8 using only one crystal. Microprocessor Interface The M-8880 uses a microprocessor interface that allows pre- cise control of transmitter and receiver functions ...
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... R Write to transmitter 0 1 Read from receiver 1 0 Write to control register 1 1 Read from status register Figure 10 Application Circuit (Single-Ended Input) 40-406-00012, Rev. G M-8880 b3 RSEL Function b3 C/R Page 6 Figure 9 Equations Table 7 CRA Bit Postions IRQ CP/DTMF TOUT Table 8 CRB Bit Positions ...
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... All voltages referenced to V unless otherwise noted noted. *Typical values are for use as design aids only, and are not guaranteed or subject to production testing. 40-406-00012, Rev. G M-8880 Table 9 Status Register Description Status Flag Set Interrupt is inactive. Cleared after status register is read. ...
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... Frequency deviation (f = 3.5795 MHz) Output load resistance Microprocessor interface 2 cycle period 2 high pulse width 2 low pulse width 2 rise and fall time Address, R/W hold time Address, R/W setup time (prior to 2) 40-406-00012, Rev. G M-8880 Table 12 AC Characteristics SYMBOL MIN -29 27.5 — — ± 1.5% ± ± 3.5% — ...
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... Maximum capacitive load, GS Maximum resistive load, GS Common mode range (no load) All voltages referenced to unless otherwise noted. V *Typical values are for use as design aids only, and are not guaranteed or subject to production testing. 40-406-00012, Rev. G M-8880 Table 12 AC Characteristics (continued) Symbol Min t 22 ...
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... Rev. G M-8880 Figure 11 Timing Diagrams Figure 12 Test Loads Page 10 www.clare.com ...
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... Maximum allowable dropout during valid DTMF signal Time to detect the presence of valid DTMF signals Time to detect the absence of valid DTMF signals Guard time, tone present. GTP t Guard time, tone absent. GTA 40-406-00012, Rev. G M-8880 Figure 13 Timing Diagrams Page 11 www.clare.com ...
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... Rev. G M-8880 .093 A1 .004 b .013 D .496 E .291 e H .394 L .016 Figure 14 Package Dimensions Page 12 Tolerances Inches Metric (mm) Min Max Min Max .210 5.33 .015 .38 .014 .022 .36 .56 .045 .070 1.14 1.78 .008 .014 .20 .36 .980 1.060 24 ...
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... Clare reserves the right to change the specification and circuitry, without notice time. The products de- scribed in this document are not intended for use in medical implantation or other direct life support applications where malfunction may result in direct physical harm, injury or death to a person. ...