ZARLINK MT8985APR1

CMOS ST-BUSTM Family
MT8985
Enhanced Digital Switch
Data Sheet
Features
September 2005
•
256 x 256 channel non-blocking switch
•
Programmable frame integrity for wideband
channels
•
Automatic identification of ST-BUS/GCI interface
backplanes
•
Per channel tristate control
•
Patented message mode
•
Non-multiplexed microprocessor interface
•
Single +5 volt supply
•
Available in DIP-40, PLCC-44 and QFP-44
packages
•
Ordering Information
MT8985AE
40 Pin PDIP
Tubes
MT8985AP
44 Pin PLCC
Tubes
MT8985AL
44 Pin MQFP Trays
MT8985APR 44 Pin PLCC
Tape & Reel
MT8985AP1 44 Pin PLCC* Tubes
MT8985APR1 44 Pin PLCC* Tape & Reel
MT8985AE1 40 Pin PDIP*
Tubes
MT8985AL1 44 Pin MQFP* Trays
*Pb Free Matte Tin
-40°C to +85°C
Switch (DX). It is pin compatible with the MT8980D and
retains all of the MT8980D's functionality. This VLSI
device is designed for switching PCM-encoded voice
or data, under microprocessor control, in digital
exchanges,
PBXs
and
any
ST-BUS/MVIP
environment. It provides simultaneous connections for
up to 256 64 kb/s channels. Each of the eight serial
inputs and outputs consist of 32 64 kbit/s channels
multiplexed to form a 2048 kbit/s stream. As the main
function in switching applications, the device provides
per-channel selection between variable or constant
throughput delays. The constant throughput delay
feature allows grouped channels such as ISDN H0 to
be switched through the device maintaining its
sequence integrity. The MT8985 is ideal for medium
sized mixed voice/data switch and voice processing
applications.
Pin compatible with MT8980 device
Applications
•
•
•
•
•
•
Medium size digital switch matrices
Hyperchannel switching (e.g., ISDN H0)
ST-BUS/MVIP™ interface functions
Serial bus control and monitoring
Centralized voice processing systems
Data multiplexer
Description
The MT8985 Enhanced Digital Switch device is an
upgraded version of the popular MT8980D Digital
C4i
VDD
F0i
VSS
Frame
Counter
STi0
ODE
Output
MUX
STi1
STi2
STi3
STi4
STi5
Serial
to
Parallel
Converter
Data
Memory
Control Register
Connection
Memory
STi6
STi7
STo0
STo1
Parallel
to
Serial
Converter
R/W A5/
A0
DTA D7/
D0
STo3
STo4
STo5
STo6
STo7
Control Interface
DS CS
STo2
CSTo
Figure 1 - Functional Block Diagram
1
Zarlink Semiconductor Inc.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 1997-2005, Zarlink Semiconductor Inc. All Rights Reserved.
MT8985
Data Sheet
Changes Summary
The following table captures the changes from the May 2005 issue.
Change
Figure 3 - “Address Memory Map“
•
corrected Address Memory Map
44 PIN PLCC
44
43
42
41
40
39
38
37
36
35
34
STo3
STo4
STo5
STo6
STo7
VSS
D0
D1
D2
D3
D4
STi3
STi4
STi5
STi6
STi7
VDD
F0i
C4i
A0
A1
A2
1
2
3
4
5
6
7
8
9
10
11
33
32
31
30
29
28
27
26
25
24
23
12
13
14
15
16
17
18
19
20
21
22
6 5 4 3 2 1 44 43 42 41 40
7
39
8
38
9
37
10
36
11
35
12
34
13
33
14
32
15
31
16
30
17
29
18 19 20 21 22 23 24 25 26 27 28
NC
A3
A4
A5
DS
R/W
CS
D7
D6
D5
NC
STi3
STi4
STi5
STi6
STi7
VDD
F0i
C4i
A0
A1
A2
NC
STi2
STi1
STi0
DTA
CSTo
ODE
STo0
STo1
STo2
NC
NC
STi2
STi1
STi0
DTA
CSTo
ODE
STo0
STo1
STo2
NC
7
Item
DTA
STi0
STi1
STi2
STi3
STi4
STi5
STi6
STi7
VDD
F0i
C4i
A0
A1
A2
A3
A4
A5
DS
R/W
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
CSTo
ODE
STo0
STo1
STo2
STo3
STo4
STo5
STo6
STo7
VSS
D0
D1
D2
D3
D4
D5
D6
D7
CS
NC
A3
A4
A5
DS
R/W
CS
D7
D6
D5
NC
Page
40 PIN PLASTIC DIP
Figure 2 - Pin Connections
2
Zarlink Semiconductor Inc.
44 PIN QFP
STo3
STo4
STo5
STo6
STo7
VSS
D0
D1
D2
D3
D4
MT8985
Data Sheet
Pin Description
Pin #
40
DIP
1
2-9
44
44
PLCC QFP
2
40
Name
Description
DTA
Data Acknowledgement (Open Drain Output). This active low output indicates that
a data bus transfer is complete. A pull-up resistor is required at this output.
3-5 41-43 STi0- ST-BUS Input 0 to 7 (Inputs). Serial data input streams. These streams have 32
7-11 1-5
STi7 channels at data rates of 2.048 Mbit/s.
10
12
6
VDD
+5 Volt Power Supply rail.
11
13
7
F0i
Frame Pulse (Input): This input accepts and automatically identifies frame
synchronization signals formatted according to different backplane specifications
such as ST-BUS and GCI.
12
14
8
C4i
Clock (Input). 4.096 MHz serial clock for shifting data in and out of the data streams.
13-18 15-17 9-11 A0-A5 Address 0 to 5 (Inputs). These lines provide the address to MT8985 internal
19-21 13-15
registers.
19
22
16
DS
Data Strobe (Input). This is the input for the active high data strobe on the
microprocessor interface. This input operates with CS to enable the internal read and
write generation.
20
23
17
R/W
Read/Write (Input). This input controls the direction of the data bus lines (D0-D7)
during a microprocessor access.
21
24
18
CS
Chip Select (Input). Active low input enabling a microprocessor read or write of
control register or internal memories.
22-29 25-27 19-21 D7-D0 Data Bus 7 to 0 (Bidirectional). These pins provide microprocessor access to data
29-33 23-27
in the internal control register, connect memory high, connect memory low and data
memory.
30
34
28
VSS
Ground Rail.
31-38 35-39 29-33 STo7- ST-BUS Outputs 7 to 0 (Three-state Outputs). Serial data output streams. These
41-43 35-37 STo0 streams are composed of 32 channels at data rates of 2.048 Mbit/s.
39
44
38
ODE Output Drive Enable (Input). This is an output enable for the STo0 to STo7 serial
outputs. If this input is low STo0-7 are high impedance. If this input is high each
channel may still be put into high impedance by software control.
40
1
39
CSTo Control ST-BUS Output (Output). This output is a 2.048 Mb/s line which contains
256 bits per frame. The level of each bit is controlled by the contents of the CSTo bit
in the Connect Memory high locations.
6, 18, 12,22
34,
28,
44
40
NC
No Connection.
3
Zarlink Semiconductor Inc.
MT8985
Data Sheet
Functional Description
With the integration of voice, video and data services into the same network, there has been an increasing demand
for systems which ensure that data at N x 64 Kbit/s rates maintain frame sequence integrity while being transported
through time slot interchange circuits. Existing requirements demand time slot interchange devices performing
switching with constant throughput delay while guaranteeing minimum delay for voice channels.
The MT8985 device provides both functions and allows existing systems based on the MT8980D to be easily
upgraded to maintain the data integrity while multiple channel data are transported. The device is designed to
switch 64 kbit/s PCM or N x 64 kbit/s data. The MT8985 can provide both frame integrity for data applications and
minimum throughput switching delay for voice applications on a per channel basis.
By using Zarlink Message mode capability, the microprocessor can access input and output time slots on a per
channel basis to control devices such as the Zarlink MT8972, ISDN Transceivers and T1/CEPT trunk interfaces
through the ST-BUS interface. Different digital backplanes can be accepted by the MT8985 device without user's
intervention. The MT8985 device provides an internal circuit that automatically identifies the polarity and format of
frame synchronization input signals compatible to ST-BUS and GCI interfaces.
Device Operation
A functional block diagram of the MT8985 device is shown in Figure 1. The serial ST-BUS streams operate
continuously at 2.048 Mb/s and are arranged in 125 µs wide frames each containing 32 8-bit channels. Eight input
(STi0-7) and eight output (STo0-7) serial streams are provided in the MT8985 device allowing a complete 256 x 256
channel non-blocking switch matrix to be constructed. The serial interface clock for the device is 4.096 MHz, as
required in ST-BUS and GCI specifications.
Data Memory
The received serial data is converted to parallel format by the on-chip serial to parallel converters and stored
sequentially in a 256-position Data Memory. The sequential addressing of the Data Memory is generated by an
internal counter that is reset by the input 8 kHz frame pulse (F0i) marking the frame boundaries of the incoming
serial data streams.
Depending on the type of information to be switched, the MT8985 device can be programmed to perform time slot
interchange functions with different throughput delay capabilities on a per-channel basis. For voice applications, the
variable delay mode can be selected ensuring minimum throughput delay between input and output data. In
multiple or grouped channel data applications, the constant delay mode can be selected maintaining the integrity of
the information through the switch.
Data to be output on the serial streams may come from two sources: Data Memory or Connect Memory. Locations
in the Connect Memory, which is split into HIGH and LOW parts, are associated with particular ST-BUS output
streams. When a channel is due to be transmitted on an ST-BUS output, the data for the channel can either be
switched from an ST-BUS input (connection mode) or it can be originated from the microprocessor (message
mode). If a channel is configured in connection mode, the source of the output data is the Data Memory. If a
channel is configured in message mode, the source of the output data is the Connect Memory Low. Data destined
for a particular channel on the serial output stream is read from the Data or Connect Memory Low during the
previous channel time slot. This allows enough time for memory access and internal parallel to serial conversion.
Connection and Message Modes
In connection mode, the addresses of input source for all output channels are stored in the Connect memory Low.
The Connect Memory Low locations are mapped to each location corresponding to an output 64 kb/s channel. The
contents of the Data memory at the selected address are then transferred to the parallel to serial converters. By
having the output channel to specify the input channel through the connect memory, the user can route the same
input channel to several output channels, allowing broadcasting facility in the switch.
4
Zarlink Semiconductor Inc.
MT8985
Data Sheet
In message mode the CPU writes data to the Connect Memory Low locations which correspond to the output link
and channel number. The contents of the Connect Memory Low are transferred to the parallel to serial converter
one channel before it is to be output. The Connect Memory Low data is transmitted each frame to the output until it
is changed by the CPU.
The per-channel functions available in the MT8985 are controlled by the Connect Memory High bits, which
determine whether individual output channels are selected into specific conditions such as: message or connection
mode, variable or constant throughput delay modes, output drivers enabled or in three-state condition. In addition,
the Connect Memory High provides one bit to allow the user to control the state of the CSTo output pin.
If an output channel is set to three-state condition, the TDM serial stream output will be placed in high impedance
during that channel time. In addition to the per-channel three-state control, all channels on the TDM outputs can be
placed in high impedance at one time by pulling the ODE input pin in LOW. This overrides the individual perchannel programming on the Connect Memory High bits.
The Connect Memory data is received via the Microprocessor Interface at D0-D7 lines. The addressing of the
MT8985 internal registers, Data and Connect memories is performed through address input pins and some bits of
the device's Control register. The higher order address bits come from the Control register, which may be written or
read through the microprocessor interface. The lower order address bits come directly from the external address
line inputs. For details on the device addressing, see Software Control and Control register description.
Serial Interface Timing
The MT8985 master clock (C4i) is a 4.096 MHz allowing serial data link configuration at 2.048 Mb/s to be
implemented. The MT8985 frame synchronization pulse can be formatted according to ST-BUS or GCI interface
specifications; i.e., the frame pulse can be active in HIGH (GCI) or LOW (ST-BUS). The MT8985 device
automatically detects the presence of an input frame pulse and identifies the type of backplane present on the serial
interface. Upon determining the correct interface connected to the serial port, the internal timing unit establishes the
appropriate serial data bit transmit and sampling edges. In ST-BUS mode, every second falling edge of the 4.096
MHz clock marks a bit boundary and the input data is clocked in by the rising edge, three quarters of the way into
the bit cell. In GCI mode, every second rising edge of the 4.096 MHz clock marks the bit boundary while data
sampling is performed during the falling edge, at three quarters of the bit boundaries.
Delay through the MT8985
The transfer of information from the input serial streams to the output serial streams results in a delay through the
MT8985 device. The delay through the MT8985 device varies according to the mode selected in the V/C bit of the
connect memory high.
Variable Delay Mode
The delay in this mode is dependent only on the combination of source and destination channels and it is not
dependent on the input and output streams. The minimum delay achievable in the MT8985 device is 3 time slots. In
the MT8985 device, the information that is to be output in the same channel position as the information is input
(position n), relative to frame pulse, will be output in the following frame (channel n, frame n+1). The same occurs if
the input channel has to be output in the two channels succeeding (n+1 and n+2) the channel position as the
information is input.
The information switched to the third timeslot after the input has entered the device (for instance, input channel 0 to
output channel 3 or input channel 30 to output channel 1), is always output three channels later.
Any switching configuration that provides three or more timeslots between input and output channels, will have a
throughput delay equal to the difference between the output and input channels; i.e., the throughput delay will be
less than one frame. Table 1 shows the possible delays for the MT8985 device in Variable Delay mode:
5
Zarlink Semiconductor Inc.
MT8985
Data Sheet
Input
Channel
Output Channel
Throughput Delay
n
m=n, n+1 or n+2
m-n + 32 timeslots
n
m>n+2
m-n time slots
n
m<n
32-(n-m) time slots
Table 1 - Channel Delay for the Variable Mode Delay
Constant Delay Mode
In this mode frame integrity is maintained in all switching configurations by making use of a multiple Data-Memory
buffer technique where input channels written in any of the buffers during frame N will be read out during frame
N+2. In the MT8985, the minimum throughput delay achievable in Constant Delay mode will be 32 time slots; for
example, when input time slot 32 (channel 31) is switched to output time slot 1 (channel 0). Likewise, the maximum
delay is achieved when the first time slot in a frame (channel 0) is switched to the last time slot in the frame
(channel 31), resulting in 94 time slots of delay.
To summarize, any input time slot from input frame N will be always switched to the destination time slot on output
frame N+2. In Constant Delay mode, the device throughput delay is calculated according to the following formula:
DELAY = [32 + (32 - IN) + (OUT - 1)];
(expressed in number of time slots)
Where:
IN is the number of the input time slot
(from 1 to 32).
OUT is the number of the output time slot
(from 1 to 32).
Microprocessor Port
The MT8985 microprocessor port has pin compatibility with Zarlink MT8980 Digital Switch device providing a nonmultiplexed bus architecture. The parallel port consists of an 8 bit parallel data bus (D0-D7), six address input lines
(A0-A5) and four control lines (CS, DS, R/W and DTA). This parallel microport allows the access to the Control
registers, Connection Memory High, Connection Memory Low and the Data Memory. All locations are read/written
except for the data memory which can be read only.
Accesses from the microport to the connection memory and the data memory are multiplexed with accesses from
the input and output TDM ports. This can cause variable Data Acknowledge delays (DTA). In the MT8985 device,
the DTA output provides a maximum acknowledgement delay of 800 ns for read/write operations in the Connection
Memory. However, for operations in the Data Memory (Message Mode), the maximum acknowledgement delay can
be 1220 ns.
6
Zarlink Semiconductor Inc.
MT8985
Data Sheet
A5
A4
A3
A2
A1
A0
LOCATION
0
1
1
1
1
1
1
1
1
0
0
0
•
•
•
•
•
1
0
0
0
•
•
•
•
•
1
0
0
0
•
•
•
•
•
1
0
0
0
•
•
•
•
•
1
0
0
1
•
•
•
•
•
1
Control Register
Channel 0
Channel 1
•
•
•
•
•
Channel 31
Figure 3 - Address Memory Map
Note: "x" Don’t care
Software Control
The address lines on the microprocessor interface give access to the MT8985 internal registers and memories. If
the A5,A1,A0 address line inputs are LOW, then the MT8985 Internal Control Register is addressed (see Figure 3).
If A5 input line is HIGH, then the remaining address input lines are used to select Memory subsections of 32
locations corresponding to the number of channels per input or output stream. As explained in the Control register
description, the address input lines and the Stream Address bits (STA) of the Control register give the user the
capability of selecting all positions of the MT8985 Data and Connect memories.
The data in the Control register consists of Split memory and Message mode bits, Memory select and Stream
Address bits (see Figure 4). The memory select bits allow the Connect Memory HIGH or LOW or the Data Memory
to be chosen, and the Stream Address bits define an internal memory subsections corresponding to input or output
ST-BUS streams. Bit 7 (Split Memory) of the Control register allows split memory operation whereby reads are from
the Data memory and writes are to the Connect Memory LOW.
The Message Enable bit (bit 6) places every output channel on every output stream in message mode; i.e., the
contents of the Connect Memory LOW (CML) are output on the ST-BUS output streams once every frame unless
the ODE input pin is LOW. If ME bit is HIGH, then the MT8985 behaves as if bits 2 (Message Channel) and 0
(Output Enable) of every Connect Memory HIGH (CMH) locations were set to HIGH, regardless of the actual value.
If ME bit is LOW, then bit 2 and 0 of each Connect Memory HIGH location operates normally. In this case, if bit 2 of
the CMH is HIGH, the associated ST-BUS output channel is in Message mode. If bit 2 of the CMH is LOW, then the
contents of the CML define the source information (stream and channel) of the time slot that is to be switched to an
output.
If the ODE input pin is LOW, then all serial outputs are high-impedance. If ODE is HIGH, then bit 0 (Output Enable)
of the CMH location enables (if HIGH) or disables (if LOW) the output drivers for the corresponding individual STBUS output stream and channel.
The contents of bit 1 (CSTo) of each Connection Memory High location (see Figure 5) is output on CSTo pin once
every frame. The CSTo pin is a 2048 Mbit/s output which carries 256 bits. If CSTo bit is set HIGH, the
corresponding bit on CSTo output is transmitted in HIGH. If CSTo bit is LOW, the corresponding bit on the CSTo
output is transmitted in LOW. The contents of the 256 CSTo bits of the CMH are transmitted sequentially on to the
CSTo output pin and are synchronous to the ST-BUS streams. To allow for delay in any external control circuitry the
contents of the CSTo bit is output one channel before the corresponding channel on the ST-BUS streams. For
example, the contents of CSTo bit in position 0 (ST0, CH0) of the CMH, is transmitted synchronously with ST-BUS
channel 31, bit 7. The contents of CSTo bit in position 32 (ST1, CH0) of the CMH is transmitted during ST-BUS
channel 31 bit 6. Bit V/C (Variable/Constant Delay) on the Connect Memory High locations allow per-channel
selection between Variable and Constant throughput delay capabilities.
7
Zarlink Semiconductor Inc.
MT8985
7
6
5
4
SM
ME
X
MS1
3
MS0
Data Sheet
2
1
0
STA2
STA1
STA0
BIT
NAME
DESCRIPTION
7
SM
Split Memory. When 1, all subsequent reads are from the Data Memory and writes are to the
Connection Memory Low, except when the Control Register is accessed again. The Memory Select
bits need to be set to specify the memory for the operations. When 0, the Memory Select bits specify
the memory for subsequent operations. In either case, the Stream Address Bits select the subsection
of the memory which is made available.
6
ME
Message Enable. When 1, the contents of the Connection Memory Low are output on the Serial
Output streams except when in High Impedance. When 0, the Connection Memory bits for each
channel determine what is output.
4-3
MS1-MS0
2-0
STA2-0
Memory Select Bits. The memory select bits operate as follows:
0-0 - Not to be used
0-1 - Data Memory (read only from the CPU)
1-0 - Connection Memory Low
1-1 - Connection Memory High
Stream Address Bits 2-0. The number expressed in binary notation on these bits refers to the input
or output ST-BUS stream which corresponds to the subsection of memory made accessible for
subsequent operations.
Figure 4 - Control Register Bits
x = Don’t care
Initialization of the MT8985
On initialization or power up, the contents of the Connection Memory High can be in any state. This is a potentially
hazardous condition when multiple MT8985 ST-BUS outputs are tied together to form matrices, as these outputs
may conflict. The ODE pin should be held low on power up to keep all outputs in the high impedance condition.
8
Zarlink Semiconductor Inc.
MT8985
Data Sheet
7
6
5
4
3
2
1
0
X
V/C
X
X
X
MC
CSTo
OE
BIT
NAME
DESCRIPTION
6
V/C
Variable/Constant Throughput Delay Mode. This bit is used to select between Variable (LOW)
and Constant Delay (HIGH) modes on a per-channel basis.
2
MC
Message Channel. When 1, the contents of the corresponding location in Connection Memory
Low are output on the corresponding channel and stream. When 0, the contents of the programmed
location in Connection Memory Low act as an address for the Data Memory and so determine the
source of the connection to the location’s channel and stream.
1
CSTo
0
OE
CSTo Bit. This bit drives a bit time on the CSTo output pin.
Output Enable. This bit enables the output drivers on a per-channel basis. This allows individual
channels on individual streams to be made high-impedance, allowing switch matrices to be
constructed. A HIGH enables the driver and a LOW disables it.
Figure 5 - Connection Memory High Bits
x = Don’t care
7
6
5
4
3
2
1
0
SAB2
SAB1
SAB0
CAB4
CAB3
CAB2
CAB1
CAB0
BIT
NAME
7-5
SAB2-0*
Source Stream Address bits. These three bits are used to select eight source streams for the
connection. Bit 7 of each word is the most significant bit.
4-0*
CAB4-0*
Source Channel Address bits 0-4. These five bits are used to select 32 different source channels
for the connection (The ST-BUS stream where the channel is present is defined by bits SAB2-0).
Bit 4 is the most significant bit.
*
DESCRIPTION
If bit 2 of the corresponding Connection High location is 1 or if bit 6 of the Control Register is 1, then these entire 8 bits are output on the
channel and stream associated with this location. Otherwise, the bits are used as indicated to define the source of the connection which is
output on the channel and stream associated with this location.
Figure 6 - Connection Memory Low Bits
During the microprocessor initialization routine, the microprocessor should program the desired active paths
through the matrices, and put all other channels into the high impedance state. Care should be taken that no two
connected ST-BUS outputs drive the bus simultaneously. When this process is complete, the microprocessor
controlling the matrices can bring the ODE signal high to relinquish high impedance state control to the CMHb0s.
9
Zarlink Semiconductor Inc.
MT8985
Data Sheet
Applications
Typical Exchange, PBX or Multiplexer
Figure 7 shows a typical implementation of line cards being interconnected through a central routing matrix that can
scale up in channel capacity to accommodate different number of ports depending on the application. In a
configuration where the switched services utilize concatenated or grouped time slots to carry voice, data and video
(channels of 128, 256 Kb/s, ISDN H0 and others), the central routing matrix has to guarantee constant throughput
delay to maintain the sequence integrity between input and output channels. Figure 7 shows an example where
the MT8985 device guarantees data integrity when data flows from the T1/E1 to the S/U interface links and viceversa. Modern technologies available today such as Frame Relay network using dedicated fractional T1 are one of
the key applications for the MT8985 device.
To other lines
Basic Rate Line Card
Layers
2&3
Entity
MT8930/31
S/U
MT8910
MT8972
C
P
U
ST-BUS
ST-BUS
To other lines
ROUTING
MATRIX
MT8985’s
ST-BUS
T1/E1
Link
MT8940/
MT8941
MH89760/
MH89790
MT8920
µC
Primary Rate Card
Figure 7 - Typical Exchange, PBX or Multiplexer Configuration
10
Zarlink Semiconductor Inc.
MT8985
Data Sheet
ISDN Desktops
(2B+D)
••••••
Analog Connections
••••••
Server 2
Server 1
T1
••••••
T1
E1
Access to
Public
Network
Server 3
n x 64
Connections
(e.g. Video)
Server 4
T1/E1
Isochronous Network
Figure 8a - Private Isochronous Network
Low Latency Isochronous Network
In today's local working group environment, there is an increasing demand for solutions on interconnection of
desktop and telephone systems so that mixed voice, data and video services can be grouped together in a reliable
network allowing the deployment of multimedia services. Existing multimedia applications require a network with
predictable data transfer delays that can be implemented at a reasonable cost. The Low Latency Isochronous
Network is one of the alternatives that system designers have chosen to accommodate this requirement (see
Figure 8a). This network can be implemented using existing TDM transmission media devices such as ISDN Basic
(S or U) and Primary rates trunks (T1 and CEPT) to transport mixed voice and data signals in grouped time slots;
for example, 2B channels in case of ISDN S or U interfaces or up to 32 channels in case of a CEPT link.
Figure 8b shows a more detailed configuration whereby several PCs are connected to form an Isochronous
network. Several services can be interconnected within a single PC chassis through the standardized Multi Vendor
Integration Protocol (MVIP). Such an interface allows the distribution and interconnection of services like voice
mail, integrated voice response, voice recognition, LAN gateways, key systems, fax servers, video cards, etc.
The information being exchanged between cards through the MVIP interface on every computer as well as between
computers through T1 or CEPT links is, in general, of mixed type where 64Kb/s and N*64Kb/s channels are
grouped together. When such a mixed type of data is transferred between cards within one chassis or from one
computer to another, the sequence integrity of the concatenated channels has to be maintained. The MT8985
device suits this application and can be used to form a complete non-blocking switch matrix of 512 channels (see
Figure 9). This allows 8 pairs of ST-BUS streams to be dedicated to the MVIP side whereas the remaining 8 pairs
are used for local ancillary functions in typical dual T1/E1 interface applications (Figure 10).
Another application of the MT8985 in an MVIP environment is to build an ISDN S-interface card (Figure 11). In this
card, 7 pairs of ST-BUS streams are connected to the MVIP interface while the remaining pair is reserved for the
interconnection of Zarlink MT8930 (SNIC), MT8992 (H-PHONE) and the MVIP interface.
11
Zarlink Semiconductor Inc.
MT8985
Data Sheet
To Video, Data, Fax and other services
MVIP
BUS
Server 1
ISDN
S-Interface
ST-BUS
MT8985s
(x4)
MH89760B
MH89790B
MT8930B
••
••
•
••
MT8930B
Local T1/E1 Link
MVIP
BUS
Server 3
•
•
•
(256 PORT
SWITCH MODULE)
MH89760B/790B
Server 3
ST-BUS
MT8985s
(x4)
MH89760B/790B
•
•
•
MH89760B/790B
MT8985
MT8985
ST-BUS MH89760B
T1
MT8985
MT8985
MH89790B
E1
HDLC
Dual T1/E1 Card
Local T1/E1 Link
MH89760B
MH89790B
ST-BUS
MT8972B
or
ANALOG
••
••
•
MT8985s
(x4)
Server 2
MVIP
BUS
To Video, Data,
Fax Services
Local Environment
Public
Network Access
Figure 8b - Implementation of an Isochronous Network Using Zarlink Components
12
Zarlink Semiconductor Inc.
MT8985
8 Input Streams
From MVIP
MT8985 #1
Data Sheet
8 Output Streams
to MVIP
CSTo
MVIP Direction
8 Input On-Board
ST-BUS Streams
MT8985 #2
CSTo
MVIP Enable
MT8985
#3
MT8985
#4
Figure 9 - 512-Channel Switch Array
13
Zarlink Semiconductor Inc.
8 Output On-Board
ST-BUS Streams
MT8985
Data Sheet
MVIP HEADER
MVIP STo0-7
FDL HDLC
MT8952B
MVIP STi0-7
SWITCH
MT8985
512 Channel
Switch Matrix
SWITCH
MT8985
FDL HDLC
MT8952B
T1/E1
MH89760B
or
MH89790B
T1/E1
SWITCH
MT8985
SWITCH
MT8985
HDLC
MT8952B
MH89760B
or
MH89790B
HDLC
MT8952B
DPLL
MT8941
ANALOG
D-PHONE
MT8992/93
PC INTERFACE
Figure 10 - Dual T1/E1 Card Functional Block Diagram
14
Zarlink Semiconductor Inc.
MT8985
Data Sheet
MVIP HEADER
MVIP STo1-7
MVIP STi1-7
STi7-1
STo7-1
SWITCH
MATRIX
MT8985
STi0
STo0
S
INTERFACE
DPLL
HDLC
MT8941
MT8930B
DTMF
RECEIVER
MT8870
DIGITAL
PHONE
HDLC
MT8992/93
PC INTERFACE
Figure 11 - S-Access Card Functional Block Diagram
15
Zarlink Semiconductor Inc.
MT8985
Data Sheet
Absolute Maximum Ratings*
Parameter
Symbol
Min.
Max.
Units
-0.3
7
V
1
VDD - VSS
2
Voltage on Digital Inputs
VI
VSS-0.3
VDD+0.3
V
3
Voltage on Digital Outputs
VO
VSS-0.3
VDD+0.3
V
4
Current at Digital Outputs
IO
40
mA
5
Storage Temperature
TS
+150
°C
6
Package Power Dissipation
PD
2
W
-65
* Exceeding these values may cause permanent damage. Functional operation under these conditions is not implied.
Recommended Operating Conditions - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
Sym.
Min.
Typ.‡
Max.
Units
1
Operating Temperature
TOP
-40
25
+85
°C
2
Positive Supply
VDD
4.75
5.0
5.25
V
3
Input Voltage
VI
0
VDD
V
Test Conditions
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
DC Electrical Characteristics - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
1
2
3
4
I
N
P
U
T
S
5
6
7
8
9
10
11
O
U
T
P
U
T
S
Sym.
Supply Current
IDD
Input High Voltage
VIH
Input Low Voltage
VIL
Input Leakage (input pins)
Input Leakage (I/O pins)
IIL
Input Pin Capacitance
CI
Min.
Typ.‡
Max.
Units
10
15
mA
2.0
0.8
V
5
100
mA
8
VOH
2.4
Output High Current
IOH
10
Output Low Voltage
VOL
Output Low Current
IOL
High Impedance Leakage
IOZ
Output Pin Capacitance
CO
V
15
mA
10
5
8
VI between VSS and VDD
pF
0.4
5
Outputs unloaded
V
34
Output High Voltage
Test Conditions
V
IOH = 10 mA
Sourcing. VOH=2.4V
IOL = 5 mA
mA
Sinking. VOL = 0.4V
mA
VO between VSS and VDD
pF
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
16
Zarlink Semiconductor Inc.
MT8985
Data Sheet
VDD
Test Point
S2 is switched to VDD or
V SS when testing output
levels or high impedance
states.
RL
Output
Pin
S1
S1 is open circuit except
when testing output levels
or high impedance states.
S2
CL
VSS
VSS
Figure 12 - Output Test Load
AC Electrical Characteristics† - ST-BUS Timing - Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
Sym.
Min.
Typ.‡
Max.
Units
1 Frame Pulse width
tF0iW
2 Frame Pulse setup time
tF0iS
10
190
ns
3 Frame Pulse hold time
tF0iH
20
190
ns
4 STo delay Active to Active
tDAA
100
ns
5 STi setup time
tSTiS
20
ns
6 STi hold time
tSTiH
20
ns
7 Clock period
tC4i
200
244
300
ns
8 CK Input Low
tCL
85
122
150
ns
9 CK Input High
tCH
85
122
150
ns
10 Clock Rise/Fall Time
tr,tf
10
ns
244
45
Test Conditions
ns
CL=150 pF
† Timing is over recommended temperature & power supply voltages (VDD=5V±5%, VSS=0V, TA=–40 to 85°C).
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
17
Zarlink Semiconductor Inc.
MT8985
Data Sheet
tF0iW
F0i
2.0V
0.8V
tC4i
tF0iH
tCH
tCL
2.0V
C4i
0.8V
tf
tF0iS
tr
tDAA
STo
2.0V
Ch. 31
Bit 0
0.8V
Ch. 0
Bit 7
Ch. 0
Bit 6
tSTiS
STi
2.0V
Ch. 31
Bit 0
0.8V
Ch. 0
Bit 5
tSTiH
Ch. 0
Bit 7
Ch. 0
Bit 6
Ch. 0
Bit 5
Figure 13 - ST-BUS Timing
AC Electrical Characteristics† - GCI Timing
Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
Sym.
Min.
Typ.‡
Max.
Units
1
Clock Period
tC4i
150
244
300
ns
2
Pulse Width
tCL, tCH
73
122
150
ns
3
Frame Width High
tWFH
4
Frame Setup
tF0iS
10
190
ns
5
Frame Hold
tF0iH
20
190
ns
6
Data Delay/Clock Active to
Active
tDAA
100
ns
7
Serial Input Setup
tSTiS
20
ns
8
Serial Input Hold
tSTiH
20
ns
9
Clock Rise/Fall Time
tr,tf
244
45
ns
10
ns
† Timing is over recommended temperature & power supply voltages (VDD=5V±5%, VSS=0V, TA=–40 to 85°C).
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
18
Zarlink Semiconductor Inc.
Test Conditions
CL=150 pF
MT8985
Data Sheet
C4i
F0i
STi/
STo
bit 0
bit 1
bit 2
bit 3
Note: bit 0 identifies the first bit of the GCI frame
See Detail a
tr
C4i
tCH
tCL
tf
tC4i
2.0V
0.8V
tWFH
F0i
2.0V
0.8V
STo
tF0iS
tF0iH
2.0V
0.8V
tSTiS
tDAA
STi
tSTiH
2.0V
0.8V
Detail a
Figure 14 - GCI Timing
AC Electrical Characteristics† - Serial Streams for ST-BUS and GCI Backplanes
1
2
3
4
O
U
T
P
U
T
S
Characteristics
Sym.
STo0/7 Delay - Active to High Z
Min.
Typ.‡
Max.
Units
tSAZ
100
ns
RL=1 KΩ*, CL=150 pF
STo0/7 Delay - High Z to Active
tSZA
100
ns
CL=150 pF
Output Driver Enable Delay
tOED
65
ns
RL=1 KΩ*, CL=150 pF
CSTo Output Delay
tXCD
60
ns
CL=150 pF
0
Test Conditions
† Timing is over recommended temperature & power supply voltages.
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
* High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
19
Zarlink Semiconductor Inc.
MT8985
Data Sheet
Bit Cell Boundary
(GCI)
C4i
2.0V
0.8V
(ST-BUS)
STo0 2.4V
to
STo7 0.4V
*
tSAZ
STo0 2.4V
to
STo7 0.4V
*
tSZA
2.4V
CSTo
0.4V
tXCD
Figure 15 - Serial Outputs and External Control
ODE
2.0V
0.8V
STo0 2.4V
to
STo7 0.4V
*
*
tOED
tOED
Figure 16 - Output Driver Enable
20
Zarlink Semiconductor Inc.
MT8985
Data Sheet
AC Electrical Characteristics†- Microprocessor Bus
Voltages are with respect to ground (VSS) unless otherwise stated.
Characteristics
Sym.
Min.
Typ.‡
Max.
Units
Test Conditions
1
CS Setup from DS rising
tCSS
0
ns
2
R/W Setup from DS rising
tRWS
30
ns
3
Add setup from DS rising
tADS
5
ns
4
CS hold after DS falling
tCSH
0
ns
5
R/W hold after DS falling
tRWH
5
ns
6
Add hold after DS falling
tADH
5
ns
7
Data setup from DTA Low on Read
10
ns
CL=150 pF
8
Data hold on read
tDDR
tDHR
ns
RL=1 KΩ*,
CL=150 pF
9
Data setup on write (fast write)
tDSW
20
10 Valid Data Delay on write
(slow write)
tSWD
11 Data hold on write
tDHW
12 Acknowledgement Delay:
Reading Data Memory
Reading/Writing Conn. Memory
Writing to Control Register
Reading Control Register
tAKD
13 Acknowledgement Hold Time
tAKH
10
50
90
ns
122
8
10
ns
ns
560
300/370
47
70
1220
730/800
95
155
ns
ns
ns
ns
60
110
ns
CL=150 pF
RL=1 KΩ*,
CL=150 pF
† Timing is over recommended temperature & power supply voltages.
‡ Typical figures are at 25°C and are for design aid only: not guaranteed and not subject to production testing.
* High Impedance is measured by pulling to the appropriate rail with RL, with timing corrected to cancel time taken to discharge CL.
21
Zarlink Semiconductor Inc.
MT8985
Data Sheet
2.0V
DS
CS
0.8V
2.0V
tCSS
tCSH
0.8V
tRWH
tRWS
R/W
2.0V
0.8V
tADH
tADS
A0-A6
2.0V
0.8V
D0-D7 2.0V
READ 0.8V
VALID DATA
tDSW
tSWD
D0-D7 2.0V
WRITE 0.8V
tDHR
VALID DATA
tDDR
tDHW
tAKD
DTA
2.0V
0.8V
Figure 17 - Motorola Non-Multiplexed Bus Timing
22
Zarlink Semiconductor Inc.
tAKH
For more information about all Zarlink products
visit our Web Site at
www.zarlink.com
Information relating to products and services furnished herein by Zarlink Semiconductor Inc. or its subsidiaries (collectively “Zarlink”) is believed to be reliable.
However, Zarlink assumes no liability for errors that may appear in this publication, or for liability otherwise arising from the application or use of any such
information, product or service or for any infringement of patents or other intellectual property rights owned by third parties which may result from such application or
use. Neither the supply of such information or purchase of product or service conveys any license, either express or implied, under patents or other intellectual
property rights owned by Zarlink or licensed from third parties by Zarlink, whatsoever. Purchasers of products are also hereby notified that the use of product in
certain ways or in combination with Zarlink, or non-Zarlink furnished goods or services may infringe patents or other intellectual property rights owned by Zarlink.
This publication is issued to provide information only and (unless agreed by Zarlink in writing) may not be used, applied or reproduced for any purpose nor form part
of any order or contract nor to be regarded as a representation relating to the products or services concerned. The products, their specifications, services and other
information appearing in this publication are subject to change by Zarlink without notice. No warranty or guarantee express or implied is made regarding the
capability, performance or suitability of any product or service. Information concerning possible methods of use is provided as a guide only and does not constitute
any guarantee that such methods of use will be satisfactory in a specific piece of equipment. It is the user’s responsibility to fully determine the performance and
suitability of any equipment using such information and to ensure that any publication or data used is up to date and has not been superseded. Manufacturing does
not necessarily include testing of all functions or parameters. These products are not suitable for use in any medical products whose failure to perform may result in
significant injury or death to the user. All products and materials are sold and services provided subject to Zarlink’s conditions of sale which are available on request.
Purchase of Zarlink’s I2C components conveys a licence under the Philips I2C Patent rights to use these components in and I2C System, provided that the system
conforms to the I2C Standard Specification as defined by Philips.
Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright Zarlink Semiconductor Inc. All Rights Reserved.
TECHNICAL DOCUMENTATION - NOT FOR RESALE