3.3 VOLT TIME SLOT INTERCHANGE
DIGITAL SWITCH WITH RATE
MATCHING
2,048 x 2,048
FEATURES:
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IDT72V71623
Up to 16 serial input and output streams
Maximum 2,048 x 2,048 channel non-blocking switching
Accepts data streams at 2.048 Mb/s, 4.096 Mb/s, 8.192 Mb/s or
16.384 Mb/s
Rate matching capability: Mux/Demux mode
Output Enable Indication pins provided by dedicated pins
Per-channel Variable Delay mode for low-latency applications
Per-channel Constant Delay mode for frame integrity applica-
tions
Automatic identification of ST-BUS
®
and GCI serial streams
Automatic frame offset delay measurement
Per-stream frame delay offset programming
Per-channel high-impedance output control
Per-channel Processor mode to allow microprocessor writes to
TX streams
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Direct microprocessor access to all internal memories
Memory block programming for quick setup
IEEE-1149.1 (JTAG) Test Port
Internal Loopback for testing
Available in 144-pin Thin Quad Flatpack (TQFP) and
144-pin Ball Grid Array (BGA) packages
Operating Temperature Range -40°C to +85°C
°
°
3.3V I/O with 5V tolerant inputs and TTL compatible outputs
DESCRIPTION:
The IDT72V71623 has a maximum non-blocking switch capacity of
2,048 x 2,048 channels with data rates at 2.048 Mb/s, 4.096 Mb/s, 8.192 Mb/s
or 16.384 Mb/s. With 16 inputs and 16 outputs, a variety of rate combinations
is supported under Mux/Demux mode, to allow for switching between streams
of different data rates.
FUNCTIONAL BLOCK DIAGRAM
Vcc GND
RESET
TMS
TDI
TDO
TCK
TRST
ODE
Test Port
RX0
Loopback
RX1
RX2
RX3
RX4
RX5
RX6
RX7
RX8
RX9
RX10
RX11
RX12
RX13
RX14
RX15
Output
MUX
Data Memory
Receive
Serial Data
Streams
Transmit
Serial Data
Streams
Internal
Registers
Connection
Memory
TX0
TX1
TX2
TX3
TX4
TX5
TX6
TX7
TX8
TX9
TX10
TX11
TX12
TX13
TX14
TX15
OEI0
OEI1
OEI2
OEI3
OEI4
OEI5
OEI6
OEI7
OEI8
OEI9
OEI10
OEI11
OEI12
OEI13
OEI14
OEI15
Timing Unit
Microprocessor Interface
5903 drw01
CLK
F0i
FE/
WFPS
HCLK
DS
CS
R/W A0-A13
DTA
D0-D15
IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. The ST-BUS
®
is a trademark of Mitel Corp.
MAY 2002
DSC-5903/6
1
2002
Integrated Device Technology, Inc. All rights reserved. Product specifications subject to change without notice.
IDT72V71623 3.3V TIME SLOT INTERCHANGE
DIGITAL SWITCH 2,048 x 2,048
COMMERCIAL TEMPERATURE RANGE
PIN DESCRIPTION
SYMBOL
GND
Vcc
TX0-15
OEI0-15
NAME
Ground.
Vcc
TX Output 0 to 15
(Three-state Outputs)
Output Enable
Indication 0 to 15
(Three-state Outputs)
RX Input 0 to 15
Frame Pulse
I/O
DESCRIPTION
Ground Rail.
+3.3 Volt Power Supply.
Serial data output stream. These streams may have a data rate of 2.048 Mb/s, 4.096 Mb/s, 8.192 Mb/s,
or 16.384 Mb/s.
These pins reflect the active or three-state status for the corresponding, (TX0-15) output streams.
O
O
RX0-15
F0i
I
I
I
I
I
I
O
I
I
FE/HCLK Frame Evaluation/
HCLK Clock
CLK
Clock
TMS
Test Mode Select
TDI
TDO
TCK
TRST
Test Serial Data In
Test Serial Data Out
Test Clock
Test Reset
RESET
Device Reset
I
WFPS
DS
R/W
CS
A0-13
D0-15
DTA
Wide Frame Pulse Select
Data Strobe
Read/Write
Chip Select
Address Bus 0 to 13
Data Bus 0-15
Data Transfer
Acknowledgment
Output Drive Enable
I
I
I
I
I
I/O
O
ODE
I
Serial data input stream. These streams may have a data rate of 2.048 Mb/s, 4.096 Mb/s, 8.192 Mb/s,
or 16.384 Mb/s.
This input accepts and automatically identifies frame synchronization signals formatted according to
ST-BUS
®
and GCI specifications.
When the WFPS pin is LOW, this pin is the frame measurement input. When the WFPS pin is HIGH, the HCLK
(4.096 MHZ clock) is required for frame alignment in the wide frame pulse (WFP) mode.
Serial clock for shifting data in/out on the serial streams (RX/TX 0-15).
JTAG signal that controls the state transitions of the TAP controller. This pin is pulled HIGH by an internal
pull-up when not driven.
JTAG serial test instructions and data are shifted in on this pin. This pin is pulled HIGH by an internal pull-up
when not driven.
JTAG serial data is output on this pin on the falling edge of TCK. This pin is held in high-impedance state when
JTAG scan is not enabled.
Provides the clock to the JTAG test logic.
Asynchronously initializes the JTAG TAP controller by putting it in the Test-Logic-reset state. This pin is pulled
by an internal pull-up when not driven. This pin should be pulsed LOW on power-up, or held LOW, to ensure
that the IDT72V71623 is in the normal functional mode.
This input (active LOW) puts the IDT72V71623 in its reset state that clears the device internal counters, registers
and brings TX0-15 and microport data outputs to a high-impedance state. In normal operation, the
RESET
pin must be held LOW for a minimum of 100ns to reset the device.
When 1, enables the wide frame pulse (WFP) Frame Alignment interface. When 0, the device operates in
ST-BUS
®
/GCI mode.
This active LOW input works in conjunction with
CS
to enable the read and write operations.
This input controls the direction of the data bus lines during a microprocessor access.
Active LOW input used by a microprocessor to activate the microprocessor port of IDT72V71623.
These pins allow direct access to Connection Memory, Data Memory and internal control registers.
These pins are the data bits of the microprocessor port.
This active LOW signal indicates that a data bus transfer is complete. When the bus cycle ends, this pin drives
HIGH and then goes high-impedance, allowing for faster bus cycles with a weaker pull-up resistor. A pull-up
resistor is required to hold a HIGH level when the pin is in high-impedance.
This is the output enable control for the TX0-15 serial outputs. When ODE input is LOW and the OSB bit of
the IMS register is LOW, TX0-15 are in a high-impedance state. If this input is HIGH, the TX0-15 output
drivers are enabled. However, each channel may still be put into a high-impedance state by using the per
channel control bit in the Connection Memory.
4
IDT72V71623 3.3V TIME SLOT INTERCHANGE
DIGITAL SWITCH 2,048 x 2,048
COMMERCIAL TEMPERATURE RANGE
DESCRIPTION (CONTINUED
Output enable indications are provided through dedicated pins (one pin per
output stream) to facilitate external data bus control.
The IDT72V71623 is capable of switching up to 2,048 x 2,048 channels
without blocking. Designed to switch 64 Kbit/s PCM or N x 64 Kbit/s data, the
device maintains frame integrity in data applications and minimizes throughput
delay for voice applications on a per channel basis.
The serial input streams (RX) and serial output streams (TX) of the
IDT72V71623 can be run up to 16.384 Mb/s allowing 256 channels per 125µs
frame. Depending on the input and output data rates the device can support
up to 16 serial streams.
With two main operating modes, Processor mode and Connection Mode,
the IDT72V71623 can easily switch data from incoming serial streams (Data
Memory) or from the controlling microprocessor (Connection Memory). As
control and status information is critical in data transmission, the Processor mode
is especially useful when there are multiple devices sharing the input and output
streams.
With two main configuration modes, Regular and Mux/Demux mode the
IDT72V71623 is designed to work in a mixed data-rate environment. In Mux/
Demux mode, all of the input streams work at one data rate and the output streams
at another. Depending on the configuration, more or less serial streams will be
available on the inputs or outputs to maintain a non-blocking switch.
With data coming from multiple sources and through different paths, data
entering the device is often delayed. To handle this problem, the IDT72V71623
has a frame evaluation feature to allow individual streams to be offset from the
frame pulse in half clock-cycle intervals up to +4.5 clock cycles for speeds up
to 8 Mb/s or +2.5 clock cycles for 16 Mb/s. (See Table 8 for maximum allowable
skew).
The IDT72V71623 also provides a JTAG test access port, an internal
loopback feature, memory block programming, a simple microprocessor
interface and automatic ST-BUS
®
/GCI sensing to shorten setup time, aid in
debugging and ease use of the device without sacrificing capabilities.
OPERATING MODES
In addition to Regular mode where input and output streams are operating
at the same rate, the IDT72V71623 incorporates a rate matching function,
Mux/Demux mode. In Mux/Demux mode, all input streams are operating at
the same rate, while output streams are operating at a different rate. All
configurations are non-blocking. These modes can be entered by setting the
DR3-0 bits in the Control Register, see Table 5.
OUTPUT IMPEDANCE CONTROL
In order to put all streams in three-state, all per-channel three-state control
bits in the Connection Memory are set (MOD0 and MOD1 = 1) or both the ODE
pin and the OSB bit of the Control Register must be zero. If any combination
other than 0-0, for the ODE pin and the OSB bit, is used, the three-state control
of the streams will be left to the state of the MOD1 and MOD0 bits of the Connection
Memory. The IDT72V71623 incorporates a memory block programming
feature to facilitate three-state control after reset. See Table 1 for Output High-
Impedance Control.
SERIAL DATA INTERFACE TIMING
When a 16Mb/s serial data rate is required, the master clock frequency
will be running at 16.384MHz resulting in a single-bit per clock. For all other
cases, 2Mb/s, 4Mb/s, and 8Mb/s, the master clock frequency will be twice the
fastest data rate on the serial streams. Use Table 5 to determine clock speed
and DR3-0 bits in the Control Register to setup the device. The IDT72V71623
provides two different interface timing modes, ST-BUS
®
or GCI. The
IDT72V71623 automatically detects the presence of an input frame pulse and
identifies it as either ST-BUS
®
or GCI.
In ST-BUS
®
, when running at 16.384MHz, data is clocked out on the
falling edge and is clocked in on the subsquent rising-edge. At all other data
rates, there are two clock cycles per bit and every second falling edge of the
master clock marks a bit boundary and the data is clocked in on the rising edge
of CLK, three quarters of the way into the bit cell. See Figure 15 for timing.
In GCI format, when running at 16.384MHz, data is clocked out on the
rising edge and is clocked in on the subsquent falling edge. At all other data
rates, there are two clock cycles per bit and every second rising edge of the
master clock marks the bit boundary and data is clocked in on the falling edge
of CLK at three quarters of the way into the bit cell. See Figure 16 for timing.
INPUT FRAME OFFSET SELECTION
Input frame offset selection allows the channel alignment of individual input
streams to be offset with respect to the output stream channel alignment (i.e. F0i).
Although input data is synchronous, delays can be caused by variable path
serial backplanes and variable path lengths, which may be implemented in large
centralized and distributed switching systems. Because data is often delayed
this feature is useful in compensating for the skew between clocks.
Each input stream can have its own delay offset value by programming the
frame input offset registers (FOR, Table 7). The frame offset shown is a function
of the data rate, and can be as large as +4.5 master clock (CLK) periods forward
with a resolution of ½ clock period. To determine the maximum offset allowed
see Table 8.
SERIAL INPUT FRAME ALIGNMENT EVALUATION
The IDT72V71623 provides the frame evaluation (FE) input to determine
different data input delays with respect to the frame pulse F0i. Setting the start
frame evaluation (SFE) bit low for at least one frame starts a measurement cycle.
When the SFE bit in the Control Register is changed from low to high, the
5
FUNCTIONAL DESCRIPTION
DATA AND CONNECTION MEMORY
All data that comes in through the RX inputs go through a serial-to-parallel
conversion before being stored into internal Data Memory. The 8 KHz frame
pulse (F0i) is used to mark the 125µs frame boundaries and to sequentially
address the input channels in Data Memory. The Data Memory is only written
by the device from the RX streams and can be read from either the TX streams
or the microprocessor.
Data output on the TX streams may come from either the Serial Input Streams
(Data Memory) or from the microprocessor (Connection Memory). In the case
that RX input data is to be output, the addresses in Connection Memory are used
to specify a stream and channel of the input. The Connection Memory is setup
in such a way that each location corresponds to an output channel for each
particular stream. In that way, more than one channel can output the same data.
In Processor mode, the microprocessor writes data to the Connection Memory
locations corresponding to the stream and channel that is to be output. The lower
byte (8 least significant bits) of the Connection Memory is output every frame
until the microprocessor changes the data or mode of the channel. By using this
Processor mode capability, the microprocessor can access input and output
time-slots on a per channel basis.
The most significant bits of the Connection Memory are used to control per
channel functions such as Processor mode, Constant or Variable Delay mode,
three-state of output drivers, and the Loopback function.
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