Datasheet MT91L60AS, MT91L60AE Datasheet (MITEL)

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ISO

-CMOS

MT91L60



3 Volt Multi-Featured Codec (MFC)

Advance Information

Features

• Single 2.7- 3.6 vol t sup ply o perat ion

• Programmable µ-Law/A-Law C odec and Filte rs

• Programmab le ITU- T (G.711)/sign-mag nitude coding

• Programmab le tr ansmi t, recei ve a nd side -tone gains

• Fully different ial interf ace to hands et transduce rs - inc luding 3 00 o hm rece iver dri ver

• Flexible digi tal inter face i ncludi ng S T-BUS/SSI

• Serial mic ro port

• Single 3 vol t sup ply

• Low power o perat ion

• ITU-T G.714 comp liant

• Multiple power dow n m odes

Applications

• Battery operated equipment

• Digital tel ephon e sets

• Cellu la r rad io se ts

• Local a rea communications stations

•Pair Gain Systems

• Line cards

ISSUE 1 May 1995

Ordering Information

MT91L60AE 24 Pin Plastic DIP MT91L60AS 20 Pin SOIC

-40°C to +85°C

Descript io n

The MT91L60 3V Multi-featured Codec incorporates a built-in Filter/Codec, gain control and programmable sidetone path as well as on-chip anti-alias filters, reference voltage and bias source. The device supports both A-Law and µ-Law requirements. The MT91L60 is a true 3V device employing a fully differential architecture to ensure wide dynamic range.

Complete telephony interfaces are provided for connection to handset transducers. Internal register access is provided through a serial microport compatible with various industry standard micro-controllers.

The MT91L60 is fabricated in Mitel's ISO technology ensuring low power consumption and high reliability.

-CMOS

STB/F0i

CLOCKin

VSSD

VDD

VSSA

VBias

VRef

Dout

Din

Flexible

Digital

Interface

FILTER/CODEC GAIN

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ENCODER

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DECODER

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7dB

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-7dB

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Timing

ST-BUS

C & D

Channels

Serial Microp ort

PWRST

IC CS DA T A1 DATA2 SCLK

Figure 1 - Functional Block Diagram

Transducer

Interface

M M +

HSPKR + HSPKR -

A/µ/IRQ

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MT91L60 Advance Information

20 PIN SOIC

24 PIN PDIP

Pin Description

CS NC

1 2

3 4 5 6 7 8 9

10 11

1 2 3 4 5

6 7 8

9 10 11 12

20 19 18 17 16 15 14 13 12

24 23 22 21 20 19 18 17 16 15 14 13

VBias

VRef

PWRST A/µ/IRQ

VSSD

SCLK DATA1 DATA2

VBias

VRef PWRST A/µ/IRQ

VSSD

SCLK DATA1 DATA2

Figure 2 - Pin Connections

M + M VSSA HSPKR + HSPKR VDD CLOCKin STB/F0i Din Dout

M + M VSSA NC HSPKR + HSPKR VDD CLOCKin NC STB/F0i Din Dout

Pin #

SOIC DIP

11 V

22 V

3 4 PWRST 45 ICInternal Conne ction. Tie externally to V 56A/µ

Name Description

Bias

Ref

Bias Voltage (Output). (VDD/2) volts is available at this pin for biasing external amplifiers. Connect 0.1 µF capacitor to V

SSA

Reference Voltage for Codec (Output). Used internally. Connect 0.1 µF capacitor to V

SSA

Power-up Reset (Input). CMOS comp atib le input w ith Schm itt Trigger (active low).

for normal operation.

/IRQ A/µ - When internal control bit DEn = 0 this CMOS level compatible input pin governs

the companding law used by the filter/Code c; µ -Law when tie d to V when tied to V IRQ

- When internal control bit DEn = 1 this pin becomes an open-drain inter rupt

. Logically OR’ed with A/µ register bit.

and A-Law

output signalling valid access to the D-Channel registers in ST-BUS mode.

67 V

SSD

78 CS

Digital Groun d. Nomi nally 0 volts. Chip Select (Input). This input signal is used to select the device for microport data

transfers. Active low. CMOS level compatibl e.

810SCLKSerial Port Synch ro nou s Clo ck (In put). Data clock for microport. CMOS level

compatible.

911DATA 1Bidirectional Serial Data. Port for microprocessor serial data transfer. In Motorola/

National mode of operation, this pin becomes the dat a transmit pin only and data receive is performed on the DATA 2 pin. Input CMOS level compatib le.

10 12 DA TA 2 Serial Data Receive. In Motorola/National mode of operati on, this pin is used for

data receive. In Intel mode, serial data transmit and receive are performed on the DATA 1 pin and DATA 2 is disconnected. Input CMOS level compatible.

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Advance Information MT91L60

Pin Description (continued)

Pin #

SOIC DIP

11 13 D

Name Description

Data Output. A high impedance three-state digital output for 8 bit wide channel data

out

being sent to the Layer 1 transceiver. Data is shifted out via this pin concurrent with the rising edge of the bit clock during the timeslot defined by STB, or according to standard ST-BUS timing.

12 14 D

Data Input. A digital input for 8 bit wide channel data received from the Layer 1

transceiver. Data is sampled on the falling edge of the bit clock during the timeslot defined by STB, or according to standard ST-BUS timing. Input level is CMOS compatibl e.

13 15 STB/F0i

Data Strobe/Frame Pulse (Input). For SSI mode this input determine s the 8 bit timeslot used by the device for both transmit and receive data. This active high signal has a repetition rate of 8 kHz. Standard frame pulse defini tions ap ply in ST-BUS mode. CMOS level com patible input.

14 17 CLOCKin Clock (Input). (CM OS level compatib le). Th e clock provided to this input pin is used

for the internal device functions. For SSI mode connect the bit clock to this pin when it is 512 kHz or greater. Connect a 4096 kHz clock to this input when the available bit

15 18 V

clock is 128 kHz or 256 kHz. For ST-BUS mode connect C4i Positive Po wer Supply (Inp ut). Nominally 3 volts.

to this pin.

16 19 HSPKR- Invertin g Hand set Speaker (Outpu t). Output to the handset speaker (balanced). 17 20 HSPKR+ N on-I nver tin g Hand set Speaker (Output). Output to the handse t speaker

(balanced).

18 22 V

SSA

Analog Gr ou nd (In pu t). Nominally 0 volts.

19 23 M- Inverting Mi cro ph on e (Inp ut). Inverting input to microp hone am plif ier from the

handset microphone.

20 24 M+ Non-Inverting Micro ph one (Inp ut). Non-inverting input to microphone am plif ier

from the handset microphone.

3,9,

NC No Connect. (DIP Package only).

16,21

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MT91L60 Advance Information

Overview

The 3V Multi-featured Codec (MFC) features complete Analog/Digital and Digital/Analog conversion of audio signals (Filter/Codec) and an analog interface to a standard handset transmitter and receiver (Transducer Interface). The receiver amplifier is capable of driving a 300 ohm load.

Each of the programmable parameters within the functional blocks is accessed through a serial microcontroller port compatible with Intel MCS-51 Motorola SPI Microwire

and National Semiconductor

specifications. These para meters inc lude :

gain control, power down, mute, B-Channel select (ST-BUS mode), C&D channel control/access, law control, digital interface programming and loopback. Optionally the device may be used in a controllerless mode utilizing the power-on default settings.

Functional Description

Filter/Codec

wide dynamic range from a single 5 volt supply design. This fully differential architecture is continued into the Transducer Interface section to provide full chip realization of these capabilities for the handset functions.

A reference voltage (V

), for the conversion

Ref

requirements of the Codec section, and a bias voltage (V

), for biasing the internal analog

Bias

sections, are both generated on-chip. V brought to an external pin so that it may be used for biasing external gain setting amplifiers. A 0.1µF

capacitor must be connected from V

Bias

ground at all times. Likewise, although V be used internally, a 0.1µF capacitor from the V pin to ground is required at all times. The analog ground reference point for these two capacitors must be physically the same point. To facilitate this the V

Ref

and V

pins are situated on adjacent pins.

Bias

The transmit filter is designed to meet ITU-T G.714 specifications. The nominal gain for this filter is 0 dB (gain control = 0 dB). Gain control allows the output signal to be increased up to 7 dB. An anti-aliasing filter is included. This is a second order lowpass implementation with a corner frequency at 25 kHz.

is also

Bias

to analog

may only

Ref

The Filter/Codec block implements conversion of the analog 0-3.3 kHz speech signals to/from the digital domain compatible with 64 kb/s PCM B-Channels. Selection of companding curves and digital code assignment are programmable. These are ITU-T G.711 A-law or µ-Law, with true-sign/ Alte rnate Digit Inversion or true-sign/Inverted Magnitude coding, respectively. Optionally, sign- magnitude coding may also be selected for proprietary applications.

The Filter/Codec block also implements transmit and receive audio path gains in the analog domain. A programmable gain, voice side-tone path is also included to provide proportional transmit speech feedback to the handset receiver. This side tone path feature is disabled by default. Figure 3 depicts the nominal half-channel and side-tone gains for the MT91L60.

In the even t of PWRST

, the MT91L60 defaults such that the side-tone path is off, all programmable gains are set to 0dB and ITU-T µ-Law is selected. Further, the digital port is set to SSI mode operation at 2048 kb/s and the FDI and driver sections are powered up. (See Microport section.)

The internal architecture is fully differential to provide the best possible noise rejection as well as to allow a

The receive filter is designed to meet ITU-T G.714 specifications. The nominal gain for this filter is 0 dB (gain control = 0dB). Gain control allows t he output signal to be attenuated up to 7 dB. Filter response is peaked to compensate for the sinx/x attenuation caused by the 8 kHz sampling rate.

Side-tone is derived from the input of the Tx filter and is not subject to the gain control of the Tx filter section. Side-tone is summed into the receive handset transducer driver path after the Rx filter gain control section so that Rx gain adjustment will not affect side-tone levels. The side-tone path may be enabled/disabled with the gain control bits located in Gain Control Register 2 (address 01h).

Transmit and receive filter gains are controlled by the TxFG

-TxFG2 and RxFG0-RxFG2 control bits,

respectively. These are located in Gain Control Register 1 (address 00h). Transmit filter gain is adjustable from 0 dB to +7 dB and receive filter gain from 0dB to -7 dB, both in 1 dB increments.

Side-tone filter gain is controlled by the STG

-STG

control bits located in Gain Control Register 2 (address 01h). Side-tone gain is adjustable from

-9.96 dB to +9.96 dB in 3 .3 2 dB incremen ts .

Intel® and MCS-51® are registered trademarks of Intel Corporation Motorola® and SPI® are registered trademarks of Motorola Corporation National® and Microwire® are trademarks of National Semiconductor Corporation

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Advance Information MT91L60

Companding law selection for the Filter/Codec is provided by the A/µ

companding control bit while the co ding sch eme is controll ed by th e Smag/ ITU-T control bit. The A/µ control bit is logically OR’ed with the A/µ controllerless modes. Both A/µ

pin providing access in both controller and

and Smag/ITU-T reside in Control Register 2 (address 04h). Table 1 illustrates th es e ch o ice s.

Code

+ Full Scale 1111 1111 1000 0000 1010 1010

+ Zero 1000 0000 1111 1111 1101 0101

-Zero

(quiet code)

- Full Scale 0111 1111 0000 0000 0010 1010

Sign/

Magnitude

0000 0000 0111 1111 0101 0101

ITU-T (G.7 11)

µ-Law A-Law

Ta ble 1

Transducer Interfaces

Standard handset transducer interfaces are provided by the MT91L60. These are:

Control of this gain is provided by the TxINC control bit (G ain Co ntrol reg iste r 1, add ress 0 0h).

• The handset speaker outputs (receiver), pins HSPKR+/HSPKR-.This internally compensated fully differ ential outp ut driver is ca pab le of d rivi ng the load sh own in Figu re 4. Th e nominal handse t receive path gain may be adjusted to either 0 dB,

-6 dB or -12 d B. Control of this gai n is provided by the Rx INC contro l bit (Gain C ontrol re gister 1, address 00h ). This gain adj ustment is in addition to the programmable gain provided by the receive filter.

HSPKR +

75 Ω

150 ohm

MT91L60

75 Ω

load

(speaker)

• The handset microphone inputs (transmitter), pins M+/M-. The nominal transmit amplifier gain may be adjusted to either 6.0 dB or 15.3 dB.

Serial Port

PCM

Filter/Codec and Transducer Interface

Receive

Filter Gain

0 to -7 dB

(1 dB steps)

-6 dB

Side-tone

-9.96 to

+9. 96 dB

(3.32 dB steps)

-11 dB

Default Bypass

HSPKR -

Figure 4 - Handset Speaker Driver

HSPKR +

75Ω

HSPKR -

75Ω

Default Side-tone off

-6.0 dB or 0 dB

Receiver

Driver

Handset

Receiver

(150Ω)

PCM

out

Transmit Filter

Transmit Fil te r

Gain

0 to +7 dB

(1 dB steps)

Transmit Gain

-0.37 dB or 8.93 dB

INTERNAL TO DEVICE

Transmit

Gain

6.37 dB

Figure 3 - Audio Gain Partitioning

M+

Transmitter

Micropho ne

M-

EXTERNAL TO DEVICE

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MT91L60 Advance Information

Microport

The serial microport, compatible with Intel MCS-51 (mode 0), Motorola SPI (CPOL=0,CPHA=0) and National Semiconductor Microwire specifications provides access to all MT91L60 internal read and write registers. This microport consists of a transmit/ receive data pin (DATA1), a receive data pin (DATA2), a chip select pin (CS data clock pin (SCLK). For D-channel contention control, in ST-BUS mode, this interface provides an open-drain interrupt output (IRQ

The microport dynamically senses the state of the serial clock (SCLK) each time chip select becomes active. The device then automatically adjusts its internal timing and pin configuration to conform to Intel or Motorola/National requirements. If SCLK is high during chip select activation then Intel mode 0 timing is assumed. The DATA1 pin is defined as a bi-directional (transmit/receive) serial port and DATA2 is internally disconnected. If SCLK is low during chip select activation then Motorola/National timing is assumed. Motorola processor mode CPOL=0, CPHA=0 must be used. DATA1 is defined as the data transmit pin while DATA2 becomes the data receive pin. Although the dual port Motorola controller configuration usually supports full-duplex communication, only half-duplex communication is possible in the MT91L60. The micro must discard non-valid data which it clocks in during a valid write transfer to the MT91L60. During a valid read transfer from the MT91L60 data simultaneously clocked out by the micro is ignored by the MT91L60.

All data transfers through the microport are two-byte transfers requiring the transmission of a Command/ Address byte followed by the data byte written or read from the addressed register. CS asserted fo r th e duration of this t wo - byte transfer. As shown in Figures 5 and 6 the falling edge of CS indicates to the MT91L60 that a microport transfer is about to begin. The first 8 clock cycles of SCLK after the falling edge of CS Command/Address byte from the microcontroller. The Command/Address byte contains information detailing whether the second byte transfer will be a read or a write operation and at what address. The next 8 clock cycles are used to transfer the data byte between the MT91L60 and the microcontroller. At the end of the two-byte transfer CS to terminate the session. The rising edge of CS tri-state the output driver of DATA1 which will remain tri-stated as long as CS

Intel processors utilize least significant bit first transmission while Motorola/National processors employ most significant bit first transmission. The MT91L60 microport automatically accommodates

are always used to receive the

is high.

) and a synchronous

must remain

is brought high again

will

these two schemes for normal data bytes. However, to ensure decoding of the R/W information, the Command/Address byte is defined differently for Intel operation than it is for Motorola/ National operation. Refer to the relative timing diagrams of Figures 5 and 6.

Receive data is sampled on the rising edge of SCLK while transmit data is made available concurrent with the falling edge of SCLK.

Flexible Di gital Interf ace

A serial link is required to transport data between the MT91L60 and an external digital transmission device. The MT91L60 utilizes the ST-BUS architecture defined by Mitel Semiconductor but also supports a strobed data interface found on many standard Codec devices. This interface is commonly referred to as Synchronous Serial Interface (SSI). The combination of ST-BUS and SSI provides a Flexible Digital Interface (FDI) capable of supporting all Mitel basic rate transmission devices as well as many other 2B+D transceivers.

The required mode of operation is selected via the CSL2-0 control bits (Control Register 2, address 04h). Pin definitions alter dependent upon the operational mode selected, as described in the following subsections as well as in the Pin Description tables.

Quiet Code

The FDI can be made to send quiet code to the decoder and receive filter path by setting the RxMute bit high. Likewise, the FDI will send quiet code in the transmit path when the TxMute bit is high. Both of these control bits reside in Control Register 1 at address 03h. When either of these bits are low their respective paths function normally. The -Zero entry of Table 1 is used for the quiet code definition.

ST-BUS Mode

The ST-BUS consists of output (DSTo) and input (DSTi) serial data streams, in FDI these are named Dout and Din respectively, a synchronous clock input signal CLOCKin (C4i (F0i

). These signals are direct connections to the corresponding pins of Mitel basic rate devices. The CSL2, CSL1 and CSL0 bits are set to 1 for ST-BUS operation.

), and a framing pulse input

and address

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Advance Information MT91L60

The data streams operate at 2048 kb/s and are Time Division Multiplexed into 32 identical channels of 64 kb/s bandwidth. A frame pulse (a 244 nSec low going pulse) is used to parse the continuous serial data streams into the 32 channel TDM frames. Each frame has a 125 µSecond period translating into an 8 kHz frame rate. A valid frame begins when F0i

COMMAND/ADDRESS DATA INPUT/OUTPUT COMMAND/ADDRESS:

DATA 1 RECEIVE

DATA 1 TRANSMIT

SCLK

➀ Delays due to internal processor timing which are transparent. ② Th e MT91L60:-latches received data on the rising edge of SCLK.

➂ The falling edge of CS

subsequent byte is always data until terminated via CS

➃ A new COMMAND/ADDRESS byte may be loaded only by CS ➄ The COMMAND/ADDRESS b yte contains:

D0D1D2D3D4D5D6D

②

➂

-outputs transmit data on the falling edge of SCLK. indicates that a COMMAND/ADDRESS byte will be transmitted from the microprocessor. The

➄

➀

D0D1D2D3D4D5D6D

1 bit - Read/Write 3 bits - Addressing Data 4 bits - Unused

returning high.

logic low coincident with a falling edge of C4i to Figure 11 for detailed ST-BUS timing. C4i frequency (4096 kHz) which is twice the data rate. This clock is used to sample the data at the 3/4 bit-cell position on DSTi and to make data available on DSTo at the start of the bit-cell. C4i

is also used to

clock the MT91L60 internal functions (i.e., Filter/

➃

D0D1D2D3D4D5D6D

➃

➂

cycling high then low again.

XX A2A1A0R/W

➀

. Refer

has a

Figure 5 - Serial Port Relative Timing for Intel Mode 0

COMMAND/ADDRESS DATA INPUT/OUTPUT COMMAND/ADDRESS:

DATA 2 RECEIVE

DATA 1 TRANSMIT

SCLK

➀Delays due to internal processor timing which are transparent .

② The MT91L60:-latches received data on the rising edge of SCLK.

➂ The falling edge of CS

subsequent byte is always data until terminated via CS

➃ A new COMMAND/ADDRESS byte may be loaded only by CS ➄ The COMMAND/ADDRESS byte contains:

D7D6D5D4D3D2D1D

②

➂

-outputs transmit data on the falling edge of SCLK. indicates that a COMMAND/ADDRESS byte will be transmitted from the microprocessor. The

➄

➀

D7D6D5D4D3D2D1D0D7D6D5D4D3D2D1D

returning high.

1 bit - Read/Write 3 bits - Addressing Data 4 bits - Unused

➃

cycling high then low again.

R/W XA

➀

➂

➃

Figure 6 - Serial Port Relative Timing for Motorola Mode 00/National Microwire

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MT91L60 Advance Information

125 µ s

F0i

DSTi, DST o

CHANNEL 0 D-channel

LSB first

for D-

Channel

CHANNEL 1 C-channel

CHANNEL 2 B1-channel

MSB first for C, B1- & B2-

Channels

CHANNEL 3 B2-channel

Figure 7 - ST-BUS Channel Assignment

Codec, Digital gain and tone generation) and to provide the channel timing requirements.

The MT91L60 uses only the first four channels of the 32 channel frame. These channels are always defined, beginning with Channel 0 after the frame pulse, as shown in Figure 7 (ST-BUS channel assignments).

The first two (D & C) Channels are enabled for use by the DEN and CEN bits respectively, (Control Register 2, address 04h). ISDN basic rate service (2B+D) defines a 16 kb/s signalling (D) Channel. The MT91L60 supports transparent access to this signalling channel. ST-BUS basic rate transmission devices, which may not employ a microport, provide access to their internal control/status registers through the ST-BUS Control (C) Channel. The MT91L60 supports microport access to this C-Channel.

DEN - D-Channe l

In ST-BUS mode ac cess to the D -Channel ( transmit and receive) data is provided through an 8-bit read/ write register (address 06h). D-Channel data is accumulated in, or transmitted from this register at the rate of 2 bits/frame for 16 kb/s operation (1 bit/ frame for 8 kb/s operation). Since the ST-BUS is asynchronous, with respect to the microport, valid access to this register is controlled through the use of an interrupt (IRQ

) output. D-Channel access is

enabled via the (DEn) bit.

DEn:

When 1, ST-BUS D-channel data (1 or 2 bits/frame depending on the state of the D8 bit) is shifted into/ out of the D-channel (READ/WRITE) register.

CHANNELS 4-31

Not Used

D8:

When 1, D-Channel data is shifted at the rate of 1 bit/ frame (8 kb/s).

When 0, D-Channel data is shifted at the rate of 2 bits/frame ( 1 6 kb/s default).

16 kb/s D-Channel operation is the default mode which allows the microprocessor access to a full byte of D-Channel information every fourth ST-BUS frame. By arbitrarily assigning ST-BUS frame n as the reference frame, during which the microprocessor D-Channel read and write operations are performed, then:

(a) A microport read of address 04 hex will result in a byte of data being extracted which is composed of four di-bits (designated by roman numerals I,II,III,IV). These di-bits are composed of the two D-Channel bits received during each of frames n, n-1, n-2 and n-3. Referring to Fig. 8a: di-bit I is mapped from frame n-3, di-bit II is mapped from frame n-2, di-bit III is mapped from frame n-1 and di-bit IV is mapped from frame n.

The D-Channel read register is not preset to any particular value on power-up (PWRST

) or software

reset (RST).

(b) A microport write to Address 04 he x will result in a byte of data being loaded which is composed of four di-bits (designated by roman numerals I, II, III, IV). These di-bits are destined for the two D-Channel bits transmitted during each of frames n+1, n+2, n+3, n+4. Referring to Fig. 8a: di-bit I is mapped to frame n+1, di-bit II is mapped to frame n+2, di bit III is mapped to frame n+3 and di bit IV is mapped to frame n+4.

When 0, the receive D-channel data (READ) is still shifted into the proper register while the DSTo D-channel timeslot and IRQ

outputs are tri-stated

(default).

7-114

If no new data is written to address 04 hex , the current D-channel register contents will be continuously re-transmitted. The D-Channel write register is preset to all ones on power-up (PWRST or softwa re r es e t ( RS T).

)

Page 9

Advance Information MT91L60

IRQ

Micropo rt Rea d/Wri te A c cess

DSTo/ DSTi

n-3 n-2 n-1 n n+1 n+2 n+3 n+4*

Di-bit Group Receive D-Channel

D0 D1

No preset value

D2 D3

III

* note that fram e n+4 is equ ival en t to frame n of the next cycle.

Figure 8a - D-Channel 16 kb/s Operation

C4i

DSTo/ DSTi

IRQ

8 kb/s operation

16 kb/s operation

Di-bit Group

Transmit

D-Channel

D0 D1ID2

Power-up reset to 1111 1111

=500 nsec max

Microport Read/Write Access

III

D6 D7

=500 nsec max

pullup

Reset coincident with

Read/Write of Address 04 Hex

or next FP

, whichever occurs first

= 10 k

IRQ

Di-bit Group Receive D-Channel

Figure 8b - IRQ

n-7 n-6 n-5 n-4 n-3 n-2 n-1 n n+1

IID1IIID2IVD3VD4VID5VIID6VIII

No preset value

Di-bit Group

Transmit

D-Channel

Timing Diagram

Figure 8c - D-Channel 8 kb/s Operation

Microport Read/Write Access

n+2

IID1IIID2IV

n+3

n+4

Power-up reset to 1111 1111

n+5

VID5VIID6VIII

n+6

n+7 n+8

D-Channel

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Page 10

MT91L60 Advance Information

An interrupt output is provided (IRQ) to synchronize microprocessor access to the D-Channel register during valid ST-BUS periods only. IRQ every fourth (eighth in 8 kb/s mode) ST-BUS frame at the beginning of the third (second in 8 kb/s mode) ST-BUS bit cell period. The interrupt will be removed following a microprocessor Read or Write of Address 04 hex or upon encountering the following frames’s FP

input, whichever occurs first. To ensure D-Channel data integrity, microport read/write access to Address 04 hex must occur before the following fra me p u l se . Se e F igu r e 8b for timing.

8 kb/s operation expands the interrupt to every eight frames and processes data one-bit-per-frame. D-Channel register data is mapped according to Figure 8c.

will occur

CEn - C-Chann el

Channel 1 conveys the control/status information for the Layer 1 transceiver. C-Channel data is transferred MSB first on the ST-BUS by the MT91L60. The full 64 kb/s bandwidth is available and is assigned according to which transceiver is being used. Consult the data sheet for the selected transceiver for its C-Channel bit definitions and order of bit tran s fe r.

When CEN is high, data written to the C-Channel register (address 05h) is transmitted, most significant bit first, on DSTo. On power-up reset (PWRST C-Channel bits default to logic high. Receive C-Channel data (DSTi) is always routed to the read register regardless of this control bit's logic state.

When low, data transmission is halted and this timeslot i s tri-stated o n D STo.

) or software reset (Rst, address 03h) all

B1-Channe l and B 2-Cha nne l

Channels 2 and 3 are the B1 and B2 channels, respectively. B-channel PCM associated with the Filter/Codec and transducer audio paths is selected on an independent basis for the transmit and receive paths. TxBSel and RxBSel (Control Register 1, address 03h) are used for this purpose.

If no valid transmit path has been selected then the timeslot output on DSTo is tri-stated (see PDFDI and PDDR control bits, Control Register 1 address 03h).

SSI Mode

The SSI BUS consists of input and output serial data streams named Din and Dout respectively, a Clock input signal (CLOCKin), and a framing strobe input (STB). The frame strobe must be synchronous with, and eight cycles of, the bit clock. A 4.096 MHz master clock is also required for SSI operation if the bit clock is less than 512 kHz. The timing requirements for SSI are shown in Figures 12 & 13.

In SSI mode the MT91L60 supports only B-Channel operation. The internal C and D Channel registers used in ST-BUS mode are not functional for SSI operation. The control bits TxBSel and RxBSel, as described in the ST-BUS section, are ignored since the B-Channel timeslot is defined by the input STB strobe. Hence, in SSI mode transmit and receive B-Channel data are always in the channel defined by the STB input.

The data strobe input STB determines the 8-bit timeslot used by the device for both transmit and receive data. This is an active high signal with an 8 kHz repetition rate.

SSI operation is separated into two categories based upon the data rate of the available bit clock. If the bit clock is 512 kHz or greater then it is used directly by the internal MT91L60 functions allowing synchronous operation. If the available bit clock is 128 kHz or 256 kHz, then a 4096 kHz master clock is required to derive clocks for the internal MT91L60 functions.

Applications where Bit Clock (BCL) is below 512 kHz are designated as asynchronous. The MT91L60 will re-align its internal clocks to allow operation when the external master and bit clocks are asynchronous. Control bits CSL2, CSL1 and CSL0 in Control Register 2 (address 04h) are used to program the bit rates.

For synchronous operation data is sampled, from Din, on the falling edge of BCL during the time slot defined by the STB input. Data is made available, on Dout, on the rising edge of BCL during the time slot defined by the STB input. Dout is tri-stated at all times when STB is not true. If STB is valid but PDFDI and PDDR are not true, then quiet code will be transmitted on Dout during the valid strobe period. There is no frame delay through the FDI circuit for synchronous operation.

7-116

For asynchronous operation Dout and Din are as defined for synchronous operation except that the allowed output jitter on Dout is larger. This is due to

Page 11

Advance Information MT91L60

the resynchronization circuitry activity and will not affect operation since the bit cell period at 128 kb/s and 256 kb/s is relatively large. There is a one frame delay through the FDI circuit for asynchronous operation. Refer to the specifications of Figures 12 & 13 for both synchronous and asynchronous SSI timing.

PWRST

While the MT91L60 is held in PWRST

/Software Res et (Rs t)

no device control or functionality is possible. While in software reset (Rst=1, address 03h) only the microport is functional. Software reset can only be removed by writing Rst logic low or by setting the PWRST

pin.

3V Multi-featured Codec Register Map

After Power-up reset (PWRST

) or software reset (Rst) all control bits assume their default states; µ-Law functionality, usually 0 dB programmable gains as well as the device powered up in SSI mode 2048 kb/s operation with Dout tri-stated while there is no strobe active on STB. If a valid strobe is supplied to STB, then Dout will be active, during the defined channel.

To attain complete power-down from a normal operating condition, write PDFDI = 1 and PDDR = 1 (Control Register 1, address 03h) or put PWRST

low.

00 RxINC RxFG

RxFG

TxINC TxFG

TxFG

TxFG0Gain C on trol

01-----STG

STG

Gain C on trol

Mute RxMute TxBsel RxBsel Control

05 C

Smag/

ITU-T

CSL

Control

C-Channel

06 D

D-Channel

07----PCM/

loopen - - Loop Back

ANALOG

7-117

Page 12

MT91L60 Advance Information

Gain Control Register 1 ADDRESS = 00h WRITE/READ V ERIFY

Power Reset Value

RxINC

RxFG

RxFG1RxFG

TxINC

TxFG2TxFG1TxFG

76543210

1000 0000

Receive Gain

Setting (dB)

(default) 0

-1

-2

-3

-4

-5

-6

-7

RxFGn = Receive Filter Gain bit n

RxINC: When high, the receiver driver nominal gain is set to 0 dB. When low, this gain is -6.0 dB. TxINC: When high, the transmit amplifier nominal gain is set to 15.3 dB. When low, this gain is 6.0 dB.

RxFG

0 0 0 0 1 1 1 1

RxFG

0 0 1 1 0 0 1 1

RxFG

0 1 0 1 0 1 0 1

Transmit Gain

Setting (dB)

(default) 0

1 2 3 4 5 6 7

= Transmit Filter Gain bit n

TxFG

0 0 0 0 1 1 1 1

TxFG

0 0 1 1 0 0 1 1

TxFG

0 1 0 1 0 1 0 1

Gain Control Register 2 ADDRESS = 01h WRITE/READ V ERIFY

Power Reset Value

---- STG

STG1STG

XXXX X000

76543210

Side-tone Gain

Setting (dB)

(default) OFF

-9.96

-6.64

-3.32 0

3.32

6.64

9.96

STGn = Side-tone Gain bit n

STG

0 0 0 0 1 1 1 1

STG

0 0 1 1 0 0 1 1

STG

Note: Bits marked "-" are reserved bits and should be written with logic "0"

7-118

0 1 0 1 0 1 0 1

Page 13

Advance Information MT91L60

Path Control

---

ADDRESS = 02h WRITE/READ VER IFY

Power Reset Value

DrGain

XX00 0000

76543210

DrGain When high, the receiver driver gain is set to -6 dB, with sidetone.

When low, the receiver driver gain is set to 0 dB, with no sidetone.

Control Reg ister 1

PDFDI P DD R TxBsel RxBselRst

TxMute RxMute

ADDRESS = 03h WRITE/READ VER IFY

Power Reset Value

1100 0000

76543210

PDFDI When high, the FDI PLA and the Filter/ Cod ec are po were d down (defau lt ). When low, the FDI is active. PDDR Whe n high, the e ar driver and Filter/Cod ec are powere d down A (default). In add ition, in ST-BUS mode, the sele cted

Rst When high, a software reset occurs performing the sam e function as the hardw are reset (PWRST

TxMut e W hen hig h the tra nsmit PCM st ream is i nterru pted a nd rep laced w ith qu iet cod e; thus forci ng the ou tput c ode in to a

RxMute When high the received PCM st ream is interrupted and replaced with quiet code; thus forcing the receive path into a

TxBsel When high, the transm it B2 cha nnel is functio na l in ST -BUS mo de. Wh en lo w, the t ransmi t B1 channe l is f unction al in

RxBsel When high, the recei ve B2 ch annel is fu nctional in ST-B US mode. Wh en low, t he receive B1 chann el is functi onal in

output channel i s tri-sta ted. In SSI mode the PCM output code wi ll be -zero code du ring the valid str obe per iod. The output will be tri-stated outside of the valid strobe and for the whole frame if no strobe is supplied. When low, the driver and Filter/Codec are active if PDFDI is low.

microport is no t a ffect ed. A software reset ca n be remo ved o nly by writ in g this b it low or b y a P WRST reset condition is removed.

mute state (only the output code is muted, the transmit microphone and transmit Filter/Codec are still functional). When low the full transmit path functions normally (default).

mute state. When low the full receive path functions norm al ly (default).

ST-BUS mode. Not used in SSI mode.

) except that the

. When low, the

Note: Bits marked "-" are reserved bits and should be written with logic "0"

7-119

Page 14

MT91L60 Advance Information

Control Register 2 ADDRESS = 04h WRITE/READ V ERIFY

Power Reset Value

0000 0010

CEn DEn

A/µ

Smag/ ITU-T

CSL

76543210

CEn When high, data written into the C-Channel register (address 05h) is transmitted during channel 1 on DSTo. When

DEn When high, data writte n int o the D-Cha n nel Re gister (a ddress 06 h) is tra nsm itted (2 bits/f rame ) during ch annel 0

D8 When high, D-channel operates at 8kb/s. When low, D-cha nnel operates at 16kb/s (defau lt). A/µ

Smag/ITU-T

CSL

low, the channel 1 timeslot is tri-stated on DSTo. Ch annel 1 data received on DSTi is read via the C-Channel register (address 05h) regardl ess of the state o f CEn . This control bit has sign ifican ce only for ST-B US oper ation and is ignored for SSI operation.

on DSTo. The rem aining six bits of the D-Ch annel carry no information. W hen low, the channel 0 time slot is completely tri-stat ed on DSTo . Ch an nel 0 da ta recei ve d on DSTi is read via the D-Ch anne l reg ister r eg ardle ss of the state of DEN. This control bit has significance only for ST-BUS mode and is ignored for SSI operation.

When high, A-Law encoding/decoding is selected for the MT91L60. When low, µ-Law encoding/decoding is selected.

When high, sign-magnitude code assignment is selected for the Codec input/output. When low, ITU-T code assignment is sele cted for the Codec in put/output; true sig n, inverted magnitu de (µ-Law) or true sign, alternate digit inversion (A-Law).

CSL

1 1 1 not applicable 4096 ST-BUS 100 128 4096 SSI 1 0 1 256 4096 SSI 000 512 512 SSI 001 1536 1536 SSI 010 2048 2048 SSI (default) 011 4096 4096 SSI

CSL

External bit Clock Rate

(kHz)

CLOCKin (kHz) Mode

Note: Bits marked "-" are reserved bits and should be written with logic "0"

7-120

Page 15

Advance Information MT91L60

C-Channel Register ADDRESS = 05h WRITE/READ

Power Reset Value

C7 C6 C5 C4 C2 C1 C0C3

76543210

Micro-port access to the ST-BUS C-Channel information read and write

1111 1111- write

XXXX XXXX - read

D-Channel Register

D7 D6 D5 D4 D2 D1 D0

ADDRESS = 06h WRITE/READ

Power Reset Value

1111 1111- write XXXX XXXX - read

76543210

D7-D0 Data written to this registe r will be transmitted every frame, in channel 0, if the DEn contro l bit is set (address 04h).

Loopback Register

Received D-Cha nn el data is val id, re gard less o f the st ate o f DEn. T hese b its a re va lid for ST-BU S mod e on ly and are accessible only when IRQ

indicates valid access.

ADDRESS = 07h WRITE/READ VERI FY

PCM/

ANALOG

loopen-

Power Reset Value

XXXX 0000

76543210

PCM/ANALOG This control bit functions only when loopen is set high. It is ignored when loopen is low.

For loopback oper ati on whe n thi s bit is high , th e device is co nfig ure d for d ig ital-t o-d ig ital l oopback operation. Data on Din is looped back to Dout without conversio n to the analog doma in. However, the receive D/A pa th (from Din to HSPKR

±) still functions. When low, the device is configured for analog-to-analog operation. An analog input signal at

± is looped back to the SPKR± o utput s throu gh the A/D an d D/A cir cuits as wel l as thro ugh the norm al tra nsm it A/D

path (from M

loopen When high, loopback ope ration is enabled and the loopba ck type is governed by the stat e of the PCM/ANALOG bit.

When low, loopbac ks are disabled, the device operates nor mall y and the PCM/ANALOG

± to Dout).

bit is ignored.

Note: Bits marked "-" are reserved bits and should be written with logic "0"

7-121

Page 16

MT91L60 Advance Information

Absolute Maximum Ratings

Parameter Symbol Min Max Units

1 Supply Voltage V 2 Voltage on any I/O pin V 3 Current on any I/O pin (transducers excluded) I 4 Storage Te mperature T 5 Power Dissipation (pac ka ge) P

- V

I/VO

I/IO

Recommended Operat ing Conditions - Voltages are with respect to V

Characteristics Sym Min Typ Max Uni ts Test Conditions

1 Supply Voltage V 2 CMOS Input Voltage (high) V 3 CMOS Input Voltage (low) V 4 Operating Temperature T

* Excluding PWRST

which is a Schmitt Trigger Input.

IHC

ILC

2.733.6 V V

- 40 + 85 °C

- 0.3 7 V

VSS - 0.3 VDD + 0.3 V

± 20 mA

- 65 + 150 °C

unless otherwise stated

V V

750 mW

7-122

Page 17

Advance Information MT91L60

DC Electrical Characteristics

Characteristics S ym Min Typ

1 Input HIGH Voltage CMOS inputs V 2 Input LOW Voltage CMOS inputs V 3 VBias Voltage Output V 4 Input Leakage Current I 5 Positive Going Threshold

Voltage (PWRST Negative Going T hreshold

Voltage (PWRST 6 Output HIGH Current I 7 Output LOW Current I 8 Output Lea kage Current I 9 Output Capacitance C

10 Input Capacita nce C

† DC Electrical Characteristics are over recommended temperature range & recommended power supply voltages. ‡ Typical figu res are at 25 °C and are for design aid only: not guarante ed and not subject to pro duct ion testin g.

only) only)

†

- Voltages are with respect to ground (V

2.1 V .9 V

VDD/2 V Max. Load = 10kΩ

0.1 10 µA VIN=VDD to V

2 1

0.01 10 µA V 15 pF 10 pF

IHC

ILC

Bias

T+

T-

- 2 mA VOH = 2V 2mAV

) unless otherwise stated.

‡

Max Uni ts Test Conditions

V V

= 0.4V

= VDD and V

OUT

Clockin Tolerance Characteristics (ST-BUS Mode)

Characteristics Min Ty p

1C4i

† AC Electrical Characteristics are over recommended temperature range & recommended power supply voltages. ‡ Typical figu res are at 25 °C and are for design aid only: not guarante ed and not subject to pro duct ion testin g.

Freq u en cy 4095.6 4096 40 96. 4 kHz (i.e. , 100 ppm)

‡

Max Units Test Conditions

7-123

Page 18

MT91L60 Advance Information

AC Characteristics† for A/D (Transmit) Path - 0dBm0 = 1.026V

A-Law, at the Codec. (V

Characteristics Sym Min Typ

1 Analog input equivalent to

overload decision

2 Absolute half-channel gain

M ± to Dou t G

Tolerance at all other transmit filter set tin g s (1 to 7dB)

3 Gain tracking vs. input level

ITU-T G.714 Me thod 2

4 Signal to total Distortion vs. input

level. ITU-T G.714 Me thod 2

5 Transmit Idle Channel Noise N

6 Gain relative to gain at 1020Hz

<50Hz 60Hz 200Hz 300 - 3000 Hz 3000 - 3400 Hz 4000 Hz >4600 Hz

=1.5 volts.)

Bias

A A

Li3.17 Li3.14

AX1 AX2

-0.3

-0.6

-1.6 35

29 24

-0.25

-0.9

‡

Max Units Test Conditions

4.2

4.4

4.2

4.6

6.0

15.3

±0.2 dB

0.3

0.6

1.6

-70

16.5

-69

-25

-30

0.0

0.25

-12.5

-25

for µ-Law and 1.066V

rms

Vp-p Vp-p

dB dB

dB dB dB

dBrnC0

dBm0p

dB dB dB dB dB dB dB

for

rms

µ-Law A-Law Both at Codec

Transmit filter gain=0dB setting. TxINC = 0* TxINC = 1* @1020 Hz

3 to -40 dBm0

-40 to -50 dBm0

-50 to -55 dBm0 0 to -30 dBm0

-40 dBm0

-45 dBm0 µ-Law

A-Law

7 Absolute Delay D

360 µs at frequency of minimum

delay

8 Group Delay relative to D

9 Power Supply Rejection

f=1020 Hz f=0.3 to 3 kHz f=3 to 4 kHz f=4 to 50 kHz

PSSR PSSR1 PSSR2 PSSR3

750 380 130 750

37 40 35 40

µs µs µs µs

dB dB dB dB

500-600 Hz 600 - 1000 Hz 1000 - 2600 Hz 2600 - 2800 Hz

±100mV peak signal on V

µ-law PSSR1-3 not production tested

7-124

Page 19

Advance Information MT91L60

AC Characteristics† for D/A (Rece ive) Path - 0dBm0 = 1.026V

=1.5 volts.)

Bias

Characteristics Sym Min Typ

1 Analog output at the Codec full

scale

2 Absolute half-channel gain.

A A

G G

Din to HSPKR±

G G

Tolerance at all other receive filter settings (-1 to -7dB)

3 Gain tracking vs. input level

ITU-T G.714 Me thod 2

4 Signal to total distortion vs. input

level. ITU-T G.714 Me thod 2

5 Receive Idle Channel Noise N

6 Gain relative to gain at 1020Hz

200Hz 300 - 3000 Hz 3000 - 3400 Hz 4000 Hz >4600 Hz

Lo3.17 Lo3.14

AR1 AR2 AR3 AR4

-0.3

-0.6

-1.6 35

29 24

-0.25

-0.90

‡

Max Units Test Conditions

4.183

4.331 0

-6

-12

±0.2 dB

15.5

-78.5

0.25

-12.5

for µ-Law and 1.066V

rms

Vp-p Vp-p

dB dB dB dB

0.3

0.6

1.6

dB dB dB

dBrnC0

-77

dBm0p

dB dB dB dB

-25

for A-Law, at the Codec.

rms

µ-Law A-Law

DrGain=0, RxINC =1* DrGain=0, RxINC =0* DrGain=1, RxINC =1* DrGain=1, RxINC =0* @ 1020 Hz

3 to -40 dBm0

-40 to -50 dBm0

-50 to -55 dBm0 0 to -30 dBm0

-40 dBm0

-45 dBm0 µ-Law

A-Law

7 Absolute Delay D 8 Group Delay relative to D

9 Cross talk D/A to A/D

A/D to D/A

CT CT

RT TR

240 µs at frequency of min. delay 750

380 130 750

-74

-80

µs µs µs µs

dB dB

500-600 Hz 600 - 1000 Hz 1000 - 2600 Hz 2600 - 2800 Hz

G.714.16 ITU-T

7-125

Page 20

MT91L60 Advance Information

AC Electrical Characteristics† for Side-tone Path

Characteristics Sym Min Typ

‡

Max Units Test Conditions

1 Absolute path gain

gain adjust = 0dB

AS1

AS2

-16.63

-10.63

dBdBRxINC = 0*

RxINC = 1* M± input s to HSPKR± outp uts 1000 Hz at STG2 =1

Electrical Characteristics† for Analog Outputs

Characteristics Sym Min Typ‡Max Units Test Conditions

1 EarpI ece load impedan ce E 2 All owable earpiece capacitive

load

3 Earpiece harmonic distortion E

† Electrical Characteristi cs are over recom m ende d temperatu re range & recommen ded power supply voltage s. ‡ Typical figu res are at 25 °C and are for design aid only: not guarante ed and not subj ect to product io n testing. * Note: RxINC, refer to Contro l Register 1, addre s s 00h.

260 300 ohms across HSPKR±

300 pF each pin: HSPKR+,

0.5 % 300 ohms load across HSPKR± (tol-15%), VO≤693mV Rx gain=0dB

HSPKR-

, RxINC=1*,

RMS

7-126