MT8889CE/CE-1

Manufacturer Part NumberMT8889CE/CE-1
Description6V, 10mA, integrated DTMF transceiver with adaptive micro interface. For paging systems, repeater systems/mobile radio, credit card systems, personal computers, interconnect dialers
ManufacturerMitel Semiconductor
MT8889CE/CE-1 datasheet
 


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Features
Central office quality DTMF transmitter/
receiver
Low power consumption
High speed adaptive micro interface
Adjustable guard time
Automatic tone burst mode
Call progress tone detection to -30dBm
Applications
Credit card systems
Paging systems
Repeater systems/mobile radio
Interconnect dialers
Personal computers
Description
The MT8889C is a monolithic DTMF transceiver with
call progress filter.
It is fabricated in CMOS
technology offering low power consumption and high
reliability.
D/A
TONE
Converters
Tone Burst
Control
Gating Cct.
Logic
IN+
+
Dial
Tone
-
High Group
IN-
Filter
Filter
GS
Low Group
OSC1
Filter
Oscillator
Circuit
OSC2
Control
Bias
Circuit
V
V
V
DD
Ref
SS
with Adaptive Micro Interface
MT8889CE/CE-1
MT8889CC/CC-1
MT8889CS/CS-1
MT8889CN/CN-1
The receiver section is based upon the industry
standard
transmitter
converter for low distortion, high accuracy DTMF
signalling. Internal counters provide a burst mode
such that tone bursts can be transmitted with precise
timing. A call progress filter can be selected allowing
a microprocessor to analyze call progress tones.
The MT8889C utilizes an adaptive micro interface,
which allows the device to be connected to a number
of popular microcontrollers with minimal external
logic. The MT8889C-1 is functionally identical to the
MT8889C except the receiver is enhanced to accept
lower level signals, and also has a specified low
signal rejection level.
Row and
Transmit Data
Column
Register
Counters
Status
Register
Control
Register
A
Digital
Algorithm
Control
and Code
Converter
Register
B
Receive Data
Steering
Logic
Register
Logic
ESt
St/GT
Figure 1 - Functional Block Diagram
MT8889C/MT8889C-1
Integrated DTMF Transceiver
ISSUE 2
Ordering Information
20 Pin Plastic DIP
20 Pin Ceramic DIP
20 Pin SOIC
24 Pin SSOP
-40°C to +85°C
MT8870
DTMF
receiver
while
utilizes
a
switched
capacitor
Data
Bus
Buffer
Interrupt
Logic
I/O
Control
May 1995
the
D/A
D0
D1
D2
D3
IRQ/CP
DS/RD
CS
R/W/WR
RS0
4-107

MT8889CE/CE-1 Summary of contents

  • Page 1

    ... Bias Circuit Ref SS with Adaptive Micro Interface MT8889CE/CE-1 MT8889CC/CC-1 MT8889CS/CS-1 MT8889CN/CN-1 The receiver section is based upon the industry standard transmitter converter for low distortion, high accuracy DTMF signalling. Internal counters provide a burst mode such that tone bursts can be transmitted with precise timing ...

  • Page 2

    MT8889C/MT8889C IN IN VRef VSS 15 OSC1 6 14 OSC2 7 13 TONE 8 12 R/W/ PIN CERDIP/PLASTIC DIP/SOIC Pin Description Pin # Name ...

  • Page 3

    Functional Description The MT8889C/MT8889C-1 Integrated Transceiver consists of a high performance DTMF receiver with an internal gain setting amplifier and a DTMF generator, which employs a burst counter to synthesize precise tone bursts and pauses. A call progress mode can ...

  • Page 4

    MT8889C/MT8889C-1 Following the filter section is a decoder employing digital counting techniques to frequencies of the incoming tones and to verify that they correspond to standard DTMF frequencies. A complex averaging algorithm protects against tone simulation by extraneous signals such ...

  • Page 5

    selected by the designer. Different steering arrangements may be used to select independent tone present (t tone absent (t ) guard times. This may be GTA necessary to meet system specifications which place both accept ...

  • Page 6

    MT8889C/MT8889C-1 EXPLANATION OF EVENTS A) TONE BURSTS DETECTED, TONE DURATION INVALID, RX DATA REGISTER NOT UPDATED. B) TONE #n DETECTED, TONE DURATION VALID, TONE DECODED AND LATCHED IN RX DATA REGISTER. C) END OF TONE #n DETECTED, TONE ABSENT DURATION ...

  • Page 7

    Burst Mode In certain telephony applications it is required that DTMF signals being generated are of a specific duration determined either by application or by any one of the exchange transmitter specifications currently existing. Standard DTMF signal timing can be ...

  • Page 8

    MT8889C/MT8889C-1 The Fourier components of correspond to V .... V as measured on the output 2f nf waveform. The total harmonic distortion for a dual tone can be calculated using Equation 2. V correspond to the low group amplitude and ...

  • Page 9

    The adaptive micro interface provides access to five internal registers. The read-only Receive Data Register contains the decoded output of the last valid DTMF digit received. Data entered into the write-only Transmit Data Register will determine which tone pair is ...

  • Page 10

    MT8889C/MT8889C-1 BIT NAME b0 TOUT Tone Output Control. A logic high enables the tone output; a logic low turns the tone output off. This bit controls all transmit tone functions. b1 CP/DTMF Call Progress or DTMF Mode Select. A logic ...

  • Page 11

    BIT NAME b0 IRQ b1 TRANSMIT DATA REGISTER EMPTY (BURST MODE ONLY) b2 RECEIVE DATA REGISTER FULL b3 DELAYED STEERING C1 R1 DTMF/CP INPUT R2 X-tal DTMF OUTPUT R L Notes: R1 100 374 ...

  • Page 12

    MT8889C/MT8889C-1 MMD6150 (or equivalent) TEST POINT 130 Test load for D0-D3 pins A software reset must be included at the beginning of all programs to initialize the control registers after power up. The initialization procedure should be ...

  • Page 13

    Absolute Maximum Ratings Parameter 1 Power supply voltage Voltage on any pin 3 Current at any pin (Except V DD and 4 Storage temperature 5 Package power dissipation * Exceeding these values may cause permanent damage. ...

  • Page 14

    MT8889C/MT8889C-1 Electrical Characteristics Gain Setting Amplifier - Voltages are with respect to ground (V Characteristics 1 Input leakage current 2 Input resistance 3 Input offset voltage 4 Power supply rejection 5 Common mode rejection 6 DC open loop voltage gain ...

  • Page 15

    AC Electrical Characteristics Characteristics 1 Accept Bandwidth 2 Lower freq. (REJECT) 3 Upper freq. (REJECT) 4 Call progress tone detect level (total power) † Characteristics are over recommended operating conditions unless otherwise stated ‡ Typical figures are at 25°C, V ...

  • Page 16

    MT8889C/MT8889C-1 AC Electrical Characteristics Characteristics 1 DS/RD/WR clock frequency 2 DS/RD/WR cycle period 3 DS/RD/WR low pulse width 4 DS/RD/WR high pulse width 5 DS/RD/WR rise and fall time 6 R/W setup time 7 R/W hold time 8 Address setup ...

  • Page 17

    DS Q clk* A0-A15 (RS0) R/W(read) Read Data (D3-D0) R/W (write) Write data (D3-D0 Q).Addr [MC6809 VMA.Addr [MC6800, MC6802] *microprocessor pin Figure 17 - MC6800/MC6802/MC6809 Timing Diagram t is from data to DS falling ...

  • Page 18

    MT8889C/MT8889C-1 ALE P0* A0-A7 (RS0, D0-D3 (Addr ALE.Addr * microprocessor pins Figure 19 - 8031/8051/8085 Read Timing Diagram ALE P0* (RS0, D0-D3 (Addr ALE.Addr * microprocessor ...