Thirty-two full-duplex, serial time-division multiplexed (TDM) highways.
■
Full availability, nonblocking 4096-channel time/
space switch.
■
2.048 Mbits/s (32 time slots), 4.096 Mbits/s (64
time slots), or 8.192 Mbits/s (128 time slots) data
rates, independently progr am mab le per high way.
■
64 kbits/s granularity with optional 32 kbits/s (4-bit)
and 16 kbits/s (2-bit) subrate switching, selectable
per highway.
■
Low-latency mode for voice channels.
■
Frame integrity for wideband data applications.
■
Concentration highway interface (CHI) compatible
with the IOM2, GCI, K2, SLD,
SC-Bus, and H.100.
■
Single highway clock and frame synchronization
input.
■
Independently programmable bit and byte offsets
with 1/4 bit resolution for all highways.
■
Capable of broadcasting data to the transmit highways from a variety of sources including host data.
■
High-impedance control per time slot.
■
Software-compatible family of 1K, 2K, and 4K timeslot interchangers.
Direct access to device registers, connection store,
and data store via microprocessor interface.
■
■
†
IEEE
1149.1 boundary scan (JTAG).
Test-pattern generation and checking for on-line
system testing (PRBS, QRSS, or user- defined
byte).
■
User-accessible BIST for data and connection
stores.
■
3.3 V power supply with 5 V tolerant I/O.
■
Low-power, high-density CMOS technology, and
TTL compatible switching thresholds.
■
217-pin PBGA package.
■
–40 °C to +85 °C operating temperature range.
*
MVIP
is a registered trademark of Natural Microsystems Corpo-
ration.
†
IEEE
is a registered trademark of The Institute of Electrical and
Electronics Engineers, Inc.
MVIP
*, ST-Bus,
Applications
■
Small and medium digital switch matrices.
■
Computer telephony integration (CTI).
■
Access concentrators.
■
PABX.
■
Cellular infrastructure.
■
ISP modem banks.
■
T1/E1 multiplexers.
■
Digital cross connects.
■
Digital loop carriers.
■
Multiport DS1/E1 service cards.
■
LAN/WAN gateways.
■
TDM highway data rate adaptation.
Description
The TTSI4K32T Time-Slot Interchanger (TSI)
switches data between 32 full-duplex, serial, timedivision multiplexed highways. The TTSI4K32T can
make any connection between 4096 input and output
time slots.
Each of the 32 transmit and 32 receive highways can
be independently programmed for data rate
(2.048 Mbits/s, 4.096 Mbits/s, or 8.192 Mbits/s) and
offset. The offset can range from 0 bits to 127 bytes
and 7 3/4 bits on a 8.192 Mbits/s highway. The
TTSI4K32T can perform rate adaptation between
varying speed highways as well.
The TTSI4K32T is configured via a microprocessor
interface with a demultiplexed address and data bus.
In addition to accessing the registers and connection
store, this interface can also be used to read
received time slots and specify user data for transmission.
The TTSI4K32T ensures that interchanged time slots
retain their frame integrity. Frame integrity is required
for applications that switch wideband data (i.e., ISDN
H-channels). For voice applications where low delay
is important, a low-latency mode can be selected.
Features .................................................................................................................................................................. 1
Pin Information ........................................................................................................................................................ 7
Typical TSI Application.......................................................................................................................................... 15
Small and Large TSIs............................................................................................................................................ 17
Mixed-Highway Data Rates................................................................................................................................... 20
Virtual and Physical Frames.............................................................................................................................. 21
TDM Highway Alignment at Zero Offset ............................................................................................................ 22
Principle of the Boundary Scan.......................................................................................................................... 30
Test Access Port Controller............................................................................................................................... 31
Data Store Memory ............................................................................................................................................... 51
Connection Store Memory..................................................................................................................................... 51
Absolute Maximum Ratings................................................................................................................................... 54
DS99-178PDH Replaces DS98-291TIC to Incorporate the Following Updates.................................................... 63
2Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
List of Figures
FiguresPage
Figure 1. Block Diagram of the TTSI4K32T .............................................................................................................6
Figure 3. A Typical TSI Application........................................................................................................................15
Figure 4. An 8K Time-Slot Switch Made from 4K TSIs ..........................................................................................17
Table 5. The TSI Family ........................................................................................................................................ 17
Table 6. Time-Slot Separation Required for Transmission with Minimum Latency (0 Offsets)............................. 24
Table 7. Offset Difference and Its Effect on Frame for Transmission.................................................................... 26
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Functional Description
The TTSI4K32T is a 4096 time-slot switch that can be used in a variety of ways, with some or all of the highways
active and running at different data rates. The table below lists a few of the possible combinations of switch size
and data rates. By selecting different rates for receive and transmit highways, rate adaptation can be performed
also. Each one of the 64 (32 transmit and 32 receive) highways can be independently programmed for data rate
(2.048 Mbits/s, 4.096 Mbits/s, or 8.192 Mbits/s) as well as a full range of bit (0—7.75) and byte (0—127) offsets.
This device uses a single clock (CK) and frame synchronization (FSYNC) signal for all highways. The CK rate can
be 2.048 MHz, 4.096 MHz, 8.192 MHz, or 16.384 MHz, and this speed is indicated to the device via the CKSPD
[0—2] strap pins. A pulse is expected on the FSYNC pin once every 125 µs.
Each one of the 4096 time slots can be independently programmed in any one of the data modes listed below:
■
Low latency
■
Frame integrity
■
Host data substitution
■
Idle code substitution
■
Test-pattern substitution (PRBS, QRSS, or a fixed byte)
■
High impedance
The low-latency mode causes a receive highway time slot to be transmitted as soon as possible, which is dependent on the relative offset of the input and output time slots. This mode is useful for voice channels where it is
important to keep the transmission delay to a minimum.
The frame integrity mode will guarantee that all selected time slots received in a common frame will be transmitted
together in a common frame. This mode is useful for wideband data (e.g., ISDN H-channels) where multiple time
slots received in a single frame cannot be split across two transmit frames.
The TTSI4K32T is a nonblocking DS0 (64 kbits/s channel) switch where a time slot is 8 bits. Since each Rx and Tx
highway data rate can be individually selected, the TTSI4K32T can also be used to switch time slots that are
smaller than 8 bits.
■
32 kbits/s channels (4-bit time slots) such as in compressed voice (ADPCM) applications. The TTSI4K32T will
be configured to sample the data at twice the data rate for highways carrying traffic at 2.048 Mbits/s or
4.096 Mbits/s.
■
16 kbits/s channels (2-bit time slots) such as in cellular (GSM) applications. The TTSI4K32T will be set to sample
the data at four times the data rate on a 2.048 Mbits/s highway carrying such traffic.
■
8 kbits/s channels (1-bit time slots) such as in half-rate GSM applications. This can be done by looping the data
through the TSI multiple times, thus oversampling the same data multiple times. However, in this configuration,
the total switching capacity of the device will drop and the latency will go up.
The TTSI4K32T is one in a family of 1K, 2K, and 4K TSIs. The high-impedance control per time-slot feature allows
four of the 4K devices to be connected to make an 8K time-slot switch.
If external drivers are needed on the transmit highway pins, support for 32 output enables, corresponding to the 32
transmit highways, is provided.
The device capabilities include several test features for board and device diagnostics.
■
Test-pattern checking on input time slots (PRBS, QRSS, or a fixed byte).
■
Test-pattern generation on output time slots (PRBS, QRSS, or a fixed byte).
■
JT AG on all I/O.
■
Software-controlled BIST of data store and connection store memory.
■
TEST pin for isolating the TTSI4K32T during board test.
The microprocessor interface supports two modes of operation, synchronous and asynchronous. These modes are
selected based on the MM input pin. Both modes provide an 8-bit demultiplexed address and data bus. Fifteen
address pins allow direct access to the 32 Kbyte address space. This interface provides direct access to the control
registers and data store and connection store memories.
The TTSI4K32T is fabricated using a low-power, high-density, CMOS process that nominally operates at 3.3 V with
TTL switching thresholds and 5 V tolerance on the inputs and outputs. A basic block diagram of the architecture is
shown in Figure 1.
RXD0
RXD1
RXD2
RXD3
RECEIVE
HIGHWAYS
TDM
DATA
DATA
STORE
TDM
DATA
TRANSMIT
HIGHWAYS
TXD0
TXOE0
TXD1
TXOE1
RXD30
RXD31
FSYNC
CK
CKSPD0
CKSPD1
CKSPD2
MM
PLL
AND
CK
LOGIC
DATA STORE
ADDRESS
CONNECTION
STORE
HOST ADDRESS/DATA BUS
MICROPROCESSOR INTERFACE
A[14—0] D[7—0]CSASDSR/WDT
PCLK
JTAG
TXD31
TXOE31
TCK
TDI
TMS
TRST
TDO
RESET
TEST
INT
5-5780(F).br.1
Figure 1. Block Diagram of the TTSI4K32T
6Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Pin Information
The TTSI4K32T is available in a 217-pin PBGA with 1.27 mm (50 mil) pin pitch.
U
T
R
P
N
M
L
K
J
H
G
F
E
D
C
B
A
1 234567891011121314151617
SIGNAL/PWR/GND
THERMAL B ALLS
(SHOULD BE CONNECTED TO
CIRCUIT BOARD’S GROUND PLAN)
*Iu indicates internal 100 kΩ pull-up resistor, and Id indicates 17.5 kΩ pull-down resistor.
(continued)
*
I
Reset (Active-Low).
any other clock or input signal. All flip-flops will be cleared when RESET
counters, state machines, and configuration registers will be set to the default state
following a reset.
u
I
T est (Active-Low).
TTSI4K32T device to be in a high-impedance state. This pin has an internal pull-up
resistor.
Microprocessor Mode.
handshake (equal to mode 1 of the Lucent dual T1/E1 terminator devices). When
MM = 1, the TTSI4K32T uses a synchronous type handshake which requires a host
processor clock (PCLK) input. Both modes use a demultiplexed address and data
bus.
Host Processor Clock.
0 MHz to 65 MHz.
I
Address Valid (Active-Low).
one PCLK cycle. Indicates the start of a
processor access.
I
Chip Select (Active-Low).
asserted low to enable any transfers
through the microprocessor interface.
CS
and cycle type signals defining the memory map location of the TTSI4K32T.
I
Not Used.
O
Data Transfer Acknowledge (ActiveLow).
cates that data has been written during
processor writes. Indicates that read
data is valid during processor reads.
An external pull-up is required on this
output.
Description
A low on this pin resets the TTSI4K32T. It is asynchronous to
When low, TEST
When MM = 0, the TTSI4K32T uses an asynchronous type
Synchronous Mode
should be a decode of all address
Must be tied high.
Active for one PCLK cycle. Indi-
(MM = 1)
Valid from
Valid for
This pin is
causes the output and bidirectional pins of the
is low. All
Asynchronous Mode
Unused.
Address Valid (Active-Low).
a valid address for a processor access.
Must be held low for the duration of the
access.
Chip Select (Active-Low).
asserted low to enable any transfers
through the microprocessor interface.
CS
and cycle type signals defining the memory map location of the TTSI4K32T. In
this mode, CS
tristating of DT
The input timing requirement of CS
tive to AS
Characteristics section on page 55.
Data Valid (Active-Low).
data during processor writes. The
TTSI4K32T will start driving D[7—0]
when this signal is asserted during processor reads.
Data Transfer Acknowledge (ActiveLow).
ten during processor writes. Indicates
that read data is valid during processor
reads. Once driven active, this signal is
held active until AS
removed.
An external pull-up is required on this
output.
Must be either tied high or low.
should be a decode of all address
is used to control the
at the end of the cycle.
is described in the Timing
Indicates that data has been writ-
, DS, or CS is
(MM = 0)
Indicates
This pin is
rela-
Indicates valid
12Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Pin Information
Table 4. TTSI4K32T Pin Descriptions
SymbolType
D[7—0]I/O
A[14—0]I
R/W
INTO
RXD[0—31]
FSYNCI
CKI
CKSPD[2—0]I
(continued)
*
Host Processor Data Bus.
provide an 8-bit, bidirectional data bus.
Read data is valid for one PCLK cycle
coincident with the assertion of DT
data must be held throughout the
access.
Host Processor Address Bus.
processor access. A0 is the least significant address signal and is used to select
byte locations.
I
Read/Write
a logic 1; a write cycle is indicated with a logic 0.
Interrupt.
occurred. This output will remain active until the interrupt status register has been
cleared (read). The polarity of this output is controlled through the INTP bit (bit 3) of
the general command register. The default value of this register is 0, which indicates active-high. This output is tristated until INTOE (bit 4) of the general command
register is set to 1. The polarity of this output should be selected before the pin is
enabled.
u
Receive Data Highways 0—31.
I
2.048 Mbits/s, 4.096 Mbits/s, or 8.192 Mbits/s.
Frame Synchronization.
125 µs (8 kHz). FSYNC can be active-low or active-high, but its polarity is the same
for all highways. FSYNC can be sampled on a positive or negative CK edge. Timeslot numbers and bit offsets are assigned relative to the detection of FSYNC. There
are no restrictions on the duty cycle of FSYNC as long as the setup and hold timing
requirements relative to CK are met.
Clock.
frequency can be 2.048 MHz, 4.096 MHz, 8.192 MHz, or 16.384 MHz. The frequency selection for CK must be set equal to or greater than the fastest highway
data rate.
Clock Speed Select for CK Pin.
This input is the clock reference for all the transmit and receive highways. Its
(continued)
Description
These pins
. Write
A14—A0 must remain valid throughout the entire
This signal indicates a read or write cycle. Read cycle is indicated with
.
This pin will be asserted to indicate that an interrupt condition has
Serial TDM highways receiving data at rates of
This signal indicates the beginning of a frame every
These strap pins indicate the frequency of CK:
Host Processor Data Bus.
provide an 8-bit, bidirectional data bus.
Write data must be valid for the duration
of DS
. Read data is valid while DT is
asserted.
These pins
CKSPD2
0002.048
0014.096
0108.192
01116.384
1XXReserved
TXD[0—31]O
*Iu indicates internal 100 kΩ pull-up resistor, and Id indicates 17.5 kΩ pull-down resistor.
T ransmit Data Highways 0—31.
2.048 Mbits/s, 4.096 Mbits/s, or 8.192 Mbits/s. During external driver mode, the
TXD[0—31] outputs will be continuously driven. The only exception to this is when
the TEST
tristated on a per-time-slot basis.
See Table 39, Transmit Highway 3-State Options, on page 50 for a detailed description of all methods for 3-stating the transmit highways.
CKSPD1CKSP D0CK (MHz)
Serial TDM highway transmitting data at rates of
input is asserted. When not in external driver mode, this highway can be
These output pins reflect the active/high-impedance status for the corresponding transmit highways. They are continuously driven
to reflect the status of the output enables of the transmit highways, regardless of
whether or not external driver mode is enabled via the ED (bit 6) in the general command register. The external driver for transmit highway [i] should be enabled when
TXOE[i] is a 1.
Also see Table 39, Transmit Highway 3-State Options, on page 50 for other methods of 3-stating the transmit highways.
TDI
TCKI
TMS
TRST
u
JTAG Test Data Input.
I
JTAG Test Clock.
u
JTAG Test Mode Select.
I
d
JTAG Test Reset (Active-Low).
I
Maximum 10 MHz.
To disable the JTAG interface, tie TRST
leave unconnected.
TDOO
DD
V
SS
V
DD
PLLP
V
Test Data Output.
P
3.3 V Supply.
P
Ground.
3.3 V PLL Supply.
All VDD leads must be connected to the 3.3 V supply.
VSSPLL and VDDPLL should be decoupled with a high-speed
capacitor with a value in the range of 2 µF—5 µF.
SS
PLLP
V
PLL Ground.
VSSPLL and VDDPLL should be decoupled with a high-speed capaci-
tor with a value in the range of 2 µF—5 µF.
NC—
*Iu indicates internal 100 kΩ pull-up resistor, and Id indicates internal 17.5 kΩ pull-down resistor.
No Connect.
This pin must be left unconnected.
low or
14Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Typical TSI Application
DS0 SERVICE
COMPLEX
HDLC
SYSTEM
BACKPLANE
(8.192 Mbits/s)
T1/E1 LIU AND FRAMER ICs
T7630/T7633
FORMATTERS
ECHO
CANCELLERS
V.90 MODEMS
(DSPs)
T1/E1
FRAMERS
T7230A
TFRA08C13
TSI
HIGHWAYS
X
R
MICROPROCESSOR BUS
HIGHWAYS
X
T
5-7074(F)r.2
T1/E1
LINES
T1/E1
LIUs
T7698
T7693
MICROPROCESSOR
Figure 3. A Typical TSI Application
A typical application that requires a TSI is where TDM highways that are carrying different types of data in 8-bit
time slots (64 kbits/s channels) need to be switched and sent to different destinations. For example, TDM highways may contain time slots that are carrying voice, Internet traffic, signaling information, etc.
The TSI could be programmed to select all the time slots, carrying Internet data from different Rx highways to be
put on a another Tx highway that is connected to a bank of V.90 modems. Return data from these modems would
be sent via another set of Rx highways back to the TSI, which could send the data back out over a Tx highway and
to a T1 line via a T1 framer and LIU.
Similarly, time slots containing signaling information which is HDLC formatted can be sent to a bank of HDLC formatters. Voice channels that have echo on them could be selectively sent to echo cancellers. Data that needs to
be sent to another card in the system could be put on the system backplane via optional bus drivers.
The time-slot interchanger core has a memory-based architecture. The received time slots are converted from
serial to parallel by the receive highways block and stored in an internal dual-ported memory called the data store,
see Figure 1, Block Diagram of the TTSI4K32T on page 6. These time slots are then read out of the data store in
the order specified by the connection store, converted from parallel to serial by the transmit highways section, and
sent out on the transmit highways.
All the time slots (bytes) coming into the device are stored in the data store. Each TDM highway can bring in up to
32 valid time slots at 2.048 Mbits/s, 64 time slots at 4.096 Mbits/s, or 128 time slots on an 8.192 Mbits/s highway,
during a 125 µs frame. With 32 Rx highways running at the maximum rate of 8.192 Mbits/s, the maximum capacity
of the switch will be utilized. The addresses used to retreive the data from the data store are stored in the connection store. If host substituted data is to be transmitted instead of data that was received on a TDM highway, then it
is stored in the connection store .
Any mode that is selected on a time-slot basis is typically made via the connection store. There are 8192 bytes in
the connection store, two for each time slot that can be selected for transmission. Each one of the 4096 possible
transmit time slots can be individually 3-stated. This is useful when multiple devices need to drive the same TDM
highway as a bus or backplane. For extra drive, 32 individual output enables (TXOE pins) are also provided to individually control an external bus or backplane driver, one for each transmit highway. A low latency (send as soon as
possible) or frame integrity (keep tagged time slots from the same highway together in the same frame) can also
be selected on a time-slot basis. The user also has the option to send one of 13 predefined test patterns, a userdefined byte, or one of three user-defined idle codes, on any time slot of any Tx highway.
Time slots received on any TDM highway can be easily broadcasted on any transmit highway using the connection
store. If, for example, the entire connection store is filled with all zeros, this then implies low-latency mode and that
the source for all transmitted data is Rx highway 0, time slot 0. Thus, the data received on RXD0 time slot 0 will end
up being broadcasted on all outgoing time slots.
16Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Small and Large TSIs
The TTSI4K32T is one in a family of time-slot interchanger (TSI) devices offered by Lucent Technologies Microelectronics Group. This family of devices are all software compatible since they all have similar register maps. The
larger devices of course have extra registers to configure the extra highways and also have larger connection and
data stores. However, software written for a smaller TSI will run without alterations with a larger device. The
TTSI2K32T and TTSI4K32T are also pin compatible, since they are in the same package.
Table 5. The TSI Family
DeviceTime-Slot CapacityNumber of Rx/Tx HighwaysPackage
The capacity of the TTS I1K16T can be fully utilized by receiving and/or transmitting data on all 16 highwa ys at
4.096 Mbits/s or eight highways at 8.192 Mbits/s. Similarly, the TTSI2K32T can be fully utilized by receiving and/or
transmitting data on all 32 highways at 4.096 Mbits/s or 16 highways at 8.192 Mbits/s. Other combinations of different data rates on different highways can also be used to fully utilize the TTSI1K16T and TTSI2K32T. The capacity
of the TTSI4K32T is fully utilized only when data is being received and/or transmitted on all 32 highways at
8.192 Mbits/s.
The TTSI4K32T can be used to make even larger switches; for example, an 8192 time-slot switch with 64 Rx and
64 Tx highways. The Rx and Tx highways of the 8K switch are labeled LRXD[0—63] and LTXD[0—63], respectively, in the figure below.
TTSI4K32T
#1
LRXD[0—31]
LRXD[32—63]LTXD[32—63]
TTSI4K32T
#3
TTSI4K32T
#2
LTXD[0—31]
TTSI4K32T
#4
5-7076(F)r.1
Figure 4. An 8K Time-Slot Switch Made from 4K TSIs
LRXD[0—31] are sent to both TSI #1 and #2. Similarly, LRXD[32—63] are sent to both TSI #3 and #4. The
TXD[0—31] of TSI #1 are wire-ORed with the TXD[0—31] of TSI #3, to make LTXD[0—31]. Similarly, the
TXD[0—31] of TSI #2 are wire-ORed with the TXD[0—31] of TSI #4, to make LTXD[32—63].
Now, if time slots on highway LRXD0 need to be switched to LTXD63, it can be done via TSI #2. The connection
stores of TSI #2 and #4 must be programmed such that they both never drive their TXD31 simultaneously. The
3-state per time-slot feature of the TSI allows this to be accomplished easily.
The host interface is designed to connect directly to a typical synchronous or asynchronous host bus. The interface
to the TTSI4K32T includes a separate clock, PCLK, which is used only in the synchronous interface mode. This
device will be a slave on the host bus and will provide the host microprocessor with the capability to read and write
the TTSI4K32T address space in a minimal number of clock cycles. There is no posting of writes in the host interface, and all registers and the data and connection stores are directly accessible.
Asynchronous Mode (MM = 0)
The following two timing diagrams show read and write in the asynchronous mode.
D[7—0]
A[14—0]
CS
AS
R/W
DS
DT
D[7—0]
A[14—0]
CS
AS
READ DATA
TSI READ ADDRESS
183 ns MAX
HIGH IMPEDANCE
5-6954(F).r3
Figure 5. Asynchronous Read
TSI WRITE DATA
TSI WRITE ADDRESS
R/W
183 ns MAX
DS
DT
HIGH IMPEDANCE
5-6955(F)r.3
Figure 6. Asynchronous Write
The presence of AS
retrieved or written, DT
to be asserted until AS
, CS, and DS being asserted will start the TTSI4K32T internal access. Once data has been
will be asserted indicating the TTSI4K32T is ready to terminate the access. DT will continue
, CS, or DS is negated.
The duration of an asynchronous read or write cycle will be a maximum of 183 ns. This duration is measured from
when AS
, CS, and DS are all asserted low until DT is asserted low by the TTSI4K32T.
18Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Microprocessor Interface
(continued)
Synchronous Mode (MM = 1)
The following two timing diagrams show read and write in the synchronous mode.
PCLK
D[7—0]
A[14—0]
CS
AS
R/W
DT
HIGH IMPEDANCE
Figure 7. Synchronous Read
READ ADDRESS
READ DATA
5-6956(F)r.4
PCLK
D[7—0]
A[14—0]
CS
AS
R/W
HIGH IMPEDANCE
DT
WRITE DATA
WRITE ADDRESS
5-6957(F)r.3
Figure 8. Synchronous Write
The synchronous write or read cycle is started when AS
for the TTSI4K32T to respond, CS
must be active during the first or second cycle of an access depending on the
value of CSV (bit 7) of the general command register. Once data has been retrieved or written, DT
is sampled active with the rising edge of PCLK. In order
will be asserted
for one clock, terminating the access.
The duration of a synchronous read or write cycle is a combination of two periods of time. One period is the dura-
tion of the internal cycle, which will be a maximum of 160 ns. The other time period is the initiation, termination, and
synchronization of activity on the processor bus, which will be a maximum of six PCLK cycles. The total duration of
the cycle, from the assertion of AS
to the removal of DT, will be the sum of these two periods of time.
Note:
The number of processor clock cycles can be reduced by one PCLK cycle if the CS
delivered soon enough to be sampled with AS
and CSV (bit 7) of the general command register is set to a 1.
Each receive (Rx) highway can be selected to sample at a rate of either 2.048 Mbits/s, 4.096 Mbits/s, or
8.192 Mbits/s. This rate selection is made via the HDR[1—0] field in the receive highways configuration register
(byte 2). Similarly, each transmit (Tx) highway can be programmed to clock the data out at 2.048 Mbits/s,
4.096 Mbits/s, or 8.192 Mbits/s via the transmit highway configuration register (byte 2). Thus, 64 independent data
rate selections can be made: 32 on the Rx side and 32 on the Tx side. Highways can also be selected to be idle,
i.e., neither receiving nor transmitting data.
The data rate on a receive highway does not have to match that on its corresponding transmit highway either, e.g.,
RXD0 and TXD0 data rates can be different. Data received on a 2.048 Mbits/s highway can be transmitted on a
4.096 Mbits/s or 8.192 Mbits/s highway too. All of this flexibility allows this device to be used to solve a variety of
design problems such as data rate adaptation, etc. Many slow-speed highways can also be combined and sent out
on a single high-speed highway.
The figure below depicts an example where time slots are being received on different highways at different data
rates and are being switched and sent out at a slower, same, or faster data rate. Each rectangle, labeled A—N,
represents an 8-bit time slot.
FSYNC
RXD0 (2 Mbits/s)A
RXD1 (4 Mbits/s)
TXD2 (2 Mbits/s)
TXD3 (4 Mbits/s)
TXD4 (8 Mbits/s)
CDEF
GHIJKLMNRXD2 (8 Mbits/s)
B
G
D
IJ
Figure 9. Mixed-Highway Data Rates
F
A
C
K
H
EB
LNM
5-7077(F)
20Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
TDM Highway Interface Timing
Virtual and Physical Frames
Figure 10 below shows a virtual frame offset from the physical frame. The FSYNC pulse marks the beginning of
the physical frame, but the TSI can be programmed to interpret the location of time slot 0 at any point in a frame.
Several parameters are available to make up the offset for a virtual frame with various levels of granularity. There
is XTSOFF/RTSOFF for transmit/receive time-slot offsets. This offset can be up to 31 time slots for a 2.048 Mbits/s
highway, 63 time slots for a 4.096 Mbits/s highway, or 127 time slots for an 8.192 Mbits/s highway. XBITOFF/
RBITOFF allow the setting of up to a 7-bit offset for transmit/receive frames. XFBOFF/RFBOFF allow fractional bit
offsets of 0, 1/4, 1/2, or 3/4 bits. All of these offsets mentioned above can be independently programmed for each
one of the transmit and receive highways. The maximum offset that can be introduced on an 8.192 Mbits/s highway is 127 time slots, 7 3/4 bits. The maximum offset on a 4.096 Mbits/s highway is 63 time slots and 7 3/4 bits.
The maximum offset on a 2.048 Mbits/s highway is 31 time slots, 7 3/4 bits.
The following examples indicate how virtual offsets can be used to simplify system designs. For example, data that
is being sent to the TSI on a particular Rx highway may have incurred a several time-slot delay due to processing
by HDLC formatters, echo cancellers, communication protocol processors, etc. Rather than adding an external
buffer to realign all the highway data to the next FSYNC, an offset to create a virtual frame on that Rx highway can
be used instead. On a transmit highway, for example, there may be a device downstream that has a processing
latency of N time slots. An offset of (32 – N) time slots can be added beforehand on a 2.048 Mbits/s highway so
that after processing, the TDM data is aligned to FSYNC again.
Fractional bit offsets are handy for adjusting the sampling point on a Rx highway. With a 1/4-bit resolution possible,
setup and hold time requirements on the Rx TDM highways for the TSI should be easily met. On transmit highways, fractional bit offsets can be used to shift the outgoing highway data slightly, so the destination device’s setup
and hold times can be met with adequate margins. Note that the time slot, bit, and fractional bit offsets are relative
to the highway data rate and imply different durations on different speed highways. For example, a 1/4-bit offset on
a 2.048 Mbits/s highway means 122 ns, on a 4.096 Mbits/s highway, it is 61 ns, and on an 8.192 Mbits/s highway,
it implies a 30.5 ns offset.
FSYNC
Rx HIGHWAY
Tx HIGHWAY
Rx OFFSET
PHYSICAL FRAME, N
VIRTUAL Rx FRAME, NVIRTUAL Rx FRAME, N + 1
VIRTUAL Tx FRAME, NVIRTUAL Tx FRAME, N + 1Tx OFFSET
The TDM highway interface logic is designed to make interconnection to the TTSI4K32T as simple as possible.
Consider the timing diagram shown in Figure 11 below. Assume the following configuration register settings:
■
FSYNC is active-high, FSP (bit 2) is set to 1 in the general command register.
■
FSYNC is sampled by the rising edge of CK, FSSE (bit 1) is set to 1 in the general command register.
■
The Tx and Rx highways are all set for zero bit and time-slot offset.
■
The input CK speed is equal to the highway data rate.
One can see that time slot 0 of a frame coincides with the sampling of an active FSYNC.
At that edge:
■
Bit 0 of time slot 0 is latched from the Rx highway with the coincident clock.
■
Bit 0 of time slot 0 is transmitted starting with the coincident clock.
X
HIGHWAY
R
FSYNC
CK
Rx TIME SLOT 0, BIT 0Rx TIME SLOT 0, BIT 0
FSYNC SAMPLED ACTIVE
Rx TIME SLOT 0 BIT 0 SAMPLE POINT
TX HIGHWAY
Tx TIME SLOT 0, BIT 0Tx TIME SLOT 0, BIT 1
5-6958(F)r.2
Figure 11. Synchronization to FSYNC
TDM Highway Offsets
An offset may be added to the sampling of Rx time slot 0, bit 0 or the transmission of Tx time slot 0, bit 0. This can
be done on any of the receive and/or transmit highways, totally independent from one another. This is done by setting the time-slot offset number, bit offset number, and fractional bit offset number on a per-highway basis using the
receive and transmit highway configuration registers. To illustrate this point, consider the timing diagram shown in
Figure 12 on page 23. Assume the following configuration register programming:
■
The input CK speed is set to 8.192 MHz.
■
FSYNC is active-high, FSP (bit 2) is set to 1 in the general command register.
■
FSYNC is sampled by the rising edge of CK, FSSE (bit 1) is set to 1 in the general command register.
■
The RXD0 highway is set for 3/4-bit offset and a highway data rate of 4.096 Mbits/s.
■
The TXD0 highway is set for 1-bit offset and a highway data rate of 2.048 Mbits/s.
One can see that bit 0 of the recei ve time slot 0 is sample d 1 and 1/2 CK cycles after FS YNC is sam pled active.
Since CK is set for 8.192 MHz and RXD0 is set for 4.096 Mbits/s, then 1 and 1/2 CK cycles equals 3/4 of a
4.096 Mbits/s bit period.
22Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
TDM Highway Offsets
(continued)
One can also see that bit 0 of the transmit time slot 0 is driven four CK cycles after FSYNC is sampled active.
Since CK is set for 8.192 MHz and TXD0 is set for 2.048 Mbits/s, then four CK cycles equals one 2.048 Mbits/s bit
period.
FSYNC
CK—8.192 MHz
RXD0—4.096 Mbits/s
(3/4-bit OFFSET)
TXD0—2.048 Mbits/s
(1-bit OFFSET)
TIME SLOT 63, BIT 7
TIME SLOT 31, BIT 6TIME SLOT 31, BIT 7 TIME SLOT 0, BIT 0
FSYNC SAMPLED ACTIVE
Rx TIME SLOT 0 BIT 0 SAMPLE POINT
TIME SLOT 0, BIT 0
TIME SLOT 0, BIT 1
5-7062(F)r .2
Figure 12. Highway Offsets
Reset Sequence
The reset sequence of the TTSI4K32T is related to the PLL operation. In order for the chip to be properly reset, the
PLL must have already established a lock on the CK input signal. That event will occur 250 µs after the CK input is
functioning. After the PLL is locked onto the input clock, the TTSI4K32T will be in a reset state within 200 ns. This
results in a reset time of 250.2 µs. Subsequent resets will take 200 ns, provided CK is not interrupted.
RESET
is an asynchronous signal and requires no setup or hold margins relative to any other input clock or signal.
After a reset, BIST must be run on the TTSI4K32T to bring all the memories in the device to a known state. This is
required for correct operation of the chip. See the description below Table 15, BIST Command Register (0x02), on
page 38, on how to run BIST.
Transmit time slots can be selected for low-latency (minimum delay) or for frame-integrity modes using the connection store memory.
Low Latency
Low latency causes a received time slot to be transmitted as soon as possible. This mode is useful for voice channels where minimum delay through the network is desirable. If the transmit (Tx) time slot is very close or before the
receive (Rx) time slot, then the data will be transmitted in the next frame. If a particular transmit time slot is physically later in time than the receive time slot by a certain duration (time-slot separation), then the data will be transmitted in the current frame. The latency will be equal to the separation of the two time slots involved. The maximum
latency that data can encounter through the TSI in low-latency mode is 134 µs. If this latency is sufficient for a particular application, disregard any of the following details.
The required separation that will cause the time slot to be transmitted in the current frame is as follows: the Tx
time-slot position in the physical frame must be greater than or equal to the Rx time-slot position in the physical
frame, by a duration of 2 Rx time slots + (4 + i) x 30.5176 ns, where i is the Tx highway number.
When Rx and Tx highway data rates are equal and the Rx and Tx highway offsets are set to zero, the following
table shows the result of the above relationship for various Tx highways.
Table 6.
Rx Highway
Time-Slot Separation Required for Transmission with Minimum Latency (0 Offsets)
Data Rate
(Mbits/s)
Tx Highway
Data Rate
(Mbits/s)
Time-Slot (ts) Separation Required for Transmission in Current Frame on
If data is received in time slot 0 at 2.048 Mbits/s, it could be passed through the device
transmitted on time slot 3 at 2.048 Mbits/s
■
If data is received in time slot 1 at 4.096 Mbits/s, it could be passed through the device
transmitted on time slot 4 at 4.096 Mbits/s
■
If data is received in time slot 2 at 8.192 Mbits/s, it could be passed through the device
transmitted on time slot 6 at 8.192 Mbits/s
of TXD0.
of TXD8.
of TXD31.
with minimum latency if
with minimum latency if
with minimum latency if
If the Rx highway has an offset, then the relationship can be updated. The Rx_time-slot_position is defined as the
Rx_time-slot_number + Rx_highway offset. The new relationship will determine the transmit time-slot position in
the physical frame at which the received data can be transmitted with minimum delay. The new relationship is (i =
Tx highway number)
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Low-Latency and Frame-Integrity Modes
Low Latency
For example, consider any Rx highway running at 4.096 Mbits/s using time slot 5 to receive data, with an Rx highway offset of 3 time slots. It is to be transmitted on TXD6. The right hand side of the relationship evaluates to:
5 time slots @ 4.096 Mbits/s
+3 time slots @ 4.096 Mbits/s
+2 time slots @ 4.096 Mbits/s
+
(4 + 6) x 30.5176 ns
19,836.426 ns
The results of the calculation show that the received data can be transmitted with minimum delay using a Tx time
slot located
number for transmission with minimum delay
Tx time slot 21 @ 8.192 Mbits/s
Tx time slot 11 @ 4.096 Mbits/s
Tx time slot 6 @ 2.048 Mbits/s
(continued)
19,836.426
ns (or later) into the physical frame on TXD6. With a zero offset on TXD6, the time-slot
would be:
(continued)
Frame Integrity
Frame integrity is applied to multiple transmit time slots in order to force data received in the same frame to be
transmitted together in a subsequent frame. This rule causes added delay, but it is useful for wideband data. Such
data could be ISDN BRI (2B channels) that take up two time slots on a receive highway. It could also be an ISDN
H0 channel (six contiguous time slots) that is being used to carry video.
The maximum latency through the device for any time slot marked for frame integrity mode is 378 µs. If that latency
is sufficient for a particular application, disregard any of the following details.
To understand the latency involved with frame-integrity mode, consider the following information. The definition of
frame integrity states that integrity is maintained between a particular Rx and Tx highway pair. This pair can be
made up of any Rx highway and any Tx highway.
Latency due to frame integrity mode is a function of the highway offsets of the Rx and Tx pair rather than the relative position of the time slots. Latency in this mode will be expressed in terms of physical frames. Whether time
slots received in virtual Rx frame N will end up going out in virtual Tx frame N + 1, N + 2, or N + 3 is dependent on
the relative highway Rx and Tx highway offsets. For a description of virtual frames, see Figure 10, Virtual and
Physical Frames on page 21.
Consider the following example. Assume RXD0 is switched to TXD1 with all Tx time slots marked for frame integrity (FI) on TXD1. If it is desirable to have the lowest possible latency for the data received on RXD0, then TXD1
must have a highway offset which is 3.90625 µs (1 time slot @ 2.048 Mbits/s) greater than the highway offset
selected for RXD0. In that case, time slots received in the virtual Rx frame (frame N) will be transmitted in the next
virtual Tx frame (frame N + 1).
The greatest latency will be incurred when the RXD0 offset is at least 121.09375 µs (31 time slots @
2.048 Mbits/s) greater than the offset selected for TXD1. In that case, time slots received in the current virtual Rx
frame (frame N) will be transmitted three frames later, i.e., in virtual Tx frame N + 3.
For all other RXD0 and TXD1 offset values, time slots received in the current virtual Rx frame will be transmitted
two frames later, i.e., in virtual Tx frame N + 2.
The range of Rx and Tx offsets can be independently selected from 0 µs to (125 – ∆)µs via the Rx and Tx highway
configuration registers, bytes 0 and 1, where ∆ = 1/4 bit. The offset difference (Tx highway offset – Rx highway offset) can therefore take the range from
transmission for the various cases of offset difference.
Table 7.
* The values for A, B, C, and D are specified in Table 8 below.
Table 8. Offset Difference Boundaries
Difference
Boundary
Offset Difference and Its Effect on Frame for Transmission
A ≤ offset difference < B*
B ≤ offset difference < C*
C ≤ offset difference ≤ D*
Boundary
Value
(µs)
Boundary Value in Terms of Time Slots (ts) and Bits, at Different Data Rates
(125 – ∆)µs to +(125 – ∆)µs. The table below shows the virtual frame for
−
2.048 Mbits/s4.096 Mbits/s8.192 Mbits/s
(continued)
N + 3
N + 2
N + 1
Table 7 and T able 8 can be used to determine the latency of time slots through the TSI in a frame integrity situation.
Keep in mind that the offset difference is the major factor in determining which virtual Tx frame the time slots will go
out in. The boundary values given in Table 8 are accurate to within ±1 time slot @ 8.192 Mbits/s (= ±4 bits @ 4.096
Mbits/s = ±2 bits @ 2.048 Mbits/s) and will depend on your particular register settings.
This example can be used to determine the latency of a frame integrity situation. Keep in mind that only the Tx and
Rx highway offsets are relevant when determining the number of physical frames that the transmit data will incur.
However, there is a small range of offset separation where the data will go out in either virtual Tx frame N + 2 or
N + 3, depending on the actual Rx and Tx offsets chosen.
There may be many Rx/Tx highway pairs performing frame integrity simultaneously, but the definition of frame
integrity states that integrity is maintained between each Rx and Tx pair and not across multiple receive highways.
However, in practice, if a Tx highway contains FI time slots from multiple Rx highways and those Rx highways have
the same highway offset, then all of the FI time slots will incur equal delay with frame integrity through the switch.
26Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Low-Latency and Frame-Integrity Modes
Frame Integrity
(continued)
(continued)
In the example shown below in Figure 13, a receive and transmit highway are both running at 2.048 Mbits/s. There
are 32 time slots for each 125 µs frame. The Rx and Tx highway offsets are zero. This makes the offset difference
zero. Therefore, time slots selected for FI will be transmitted two frames later.
The TSI is configured to perform the following switching function:
Tx time slot 31 is sourced from Rx time slot 0 in low-latency mode. It goes out in frame N.
Tx time slot 2 is sourced from Rx time slot 2 in low-latency mode. It goes out in frame N + 1.
Tx time slot 30 is source from Rx time slot 1 in frame-integrity mode. It goes out in frame N + 2.
Tx time slot 0 is sourced from Rx time slot 3 in frame-integrity mode. It goes out in frame N + 2.
FRAME BFRAME CF RAME DFRAME E
FSYNC
X
R
HIGHWAY
X
HIGHWAY
T
0
B
3
Z
B1B2B
2
A
3
B29B30B
Z1B
31
0
0
C
3
A
C1C2C
2
B
3
C29C30C
A1C
31
0
D
0
3
B
D1D
2
3
D
D29D30D
2
C
0
31
E
3
0B1
C
D
E1E
2
2
D
Figure 13. Mixed Low-Latency and Frame-Integrity Modes
Test-pattern generation involves selecting outgoing time slots on a particular transmit highway for use in transmitting one of 15 patterns of data. The patterns available are selected using TPS[3—0] (bits 7—4) of the T est-Pattern
Style Register (0x0A), Table 23 on page 43. The transmit highway and time slots involved are selected using the
connection store.
Using the connection store, time slots can be set for test-pattern mode and the on-chip test-pattern generator will
be the source for that transmitted data. The type of test pattern used is determined by the values in the Test-Pattern Style Register (0x0A), Table 23 on page 43. Test-pattern data can be applied to any number of time slots on
only one highway at a time. Any highway may be selected to transmit test-pattern data. The only restrictions for
selecting the time slots set for test-pattern mode are that the time slots must be from the same highway and they
must be contiguous.
The sequence for enabling test-pattern generation is as follows:
1.Set TSDSM[2—0] (bits 7—5) in byte 1 of the connection store locations which correspond to the time slots
involved in test-pattern substitution mode. Any range of time slots may be selected for test-pattern substitution
mode, starting at any time-slot position. The remaining time slots of that highway will be unaffected.
2.Set TPS[3—0] (bits 7—4) of the Test-Pattern Style Register (0x0A), Table 23 on page 43 to select the test pattern to be sent. If a fixed user-defined byte is selected for transmission via the TPS[3—0] bits, then the TestPattern Generator Data Register (0x12), Table 31 on page 45 must also be programmed.
3.Select the data rate of the test-pattern generator via GENHDR[1—0] (bits 5—4) and set STTPG (bit 7) to 1 in
the Test Command Register (0x09), Table 22 on page 42 to start transmitting a good test pattern on the
selected time slots.
In order for data to be transmitted, highways need to be enabled using XE (bit 2) of the Transmit Highway Configuration Register (Byte 2) (0x1002 + 4i), Table 35 on page 47 and GXE (bit 0) of the General Command Register
(0x00), Table 13 on page 37. This can be done before or after the above sequence.
The Tx highway that has been selected for test-pattern generation must be the only highway that has time slots
selected for test-pattern substitution mode (i.e., TSDSM[2—0] = 110) in the connection store. No time slots on any
other Tx highway may be selected for test-pattern substitution mode. If the Tx highway selected for test-pattern
generation is changed, then the previous highway must have all its time slots that were in the TSDSM[2—0] = 110
mode, to be changed to a non-test-pattern substitution mode.
Test-Pattern Checking
Test-pattern checking involves selecting incoming time slots on a particular receive highway for reception of one of
15 test patterns. The patterns available are selected by setting CPS[3—0] (bits 3—0) of the Test-Pattern Style Register (0x0A), Table 23 on page 43. The input highway and time slots involved are selected using the following registers:
■
Test-Pattern Checker Highway Register (0x0B), Table 24 on page 44
Test-pattern data can be checked on any number of time slots on only one highway at a time. Any receive highway
may be selected to check for test-pattern data. The only restriction on selecting the time slots set for testpattern checking is that the time slots must be from the same highway and they must be contiguous.
The sequence for enabling test-pattern checking is as follows:
1.Set Test-Pattern Checker Highway Register (0x0B), Table 24 on page 44 to select a highway for receiving the
test data.
28Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Test-Pattern Checking
2.Set the Test-Pattern Checker Upper Time-Slot Register (0x0C), Table 25 on page 44 and the Test-Pattern
Checker Lower Time-Slot Register (0x0D), Table 26 on page 44 to indicate the range of input time slots which
will be carrying test data. The range is inclusive of the time slots indicated in both registers. If only one time slot
is to be selected, then the upper and lower registers should be set to the same value.
3.Set CPS[3—0] (bits 3—0) of the Test-Pattern Style Register (0x0A), Table 23 on page 43 to select the test pattern to detect. If a fixed, user-defined byte is to be detected, the CTP[7—0] bits in the Test-Pattern Checker
Data Register (0x0E), Table 27 on page 44 should also be programmed with the user-defined pattern.
4.Select the data rate of the test-pattern checker via CHKHDR[1—0] (bits 3—2) and set STTPC (bit 6) in the Test
Command Register (0x09), Table 22 on page 42 to prompt the checker to attempt to lock onto the selected
test-pattern style.
If there is a need to restart the checker (i.e., the test-pattern style has changed), then STTPC (bit 6) of the Test
Command Register (0x09), Table 22 on page 42 must first be cleared to 0, and then steps 3 and 4 should be
repeated.
There is an interrupt register status bit related to the test-pattern checker. TPD (bit 5) of the Interrupt Status Register (0x07), Table 20 on page 40 is used to determine when, if ever, the pattern is detected. The TPD interrupt status bit will remain 0 until the pattern has been detected. This bit is cleared when read. Once TPD is set, it will not
be set again until the checker is instructed to relock on the test pattern by clearing and then setting STTPC (bit 6)
in the test command register.
(continued)
Error Injection
The error injection feature provides the capability to inject errors into the outgoing test-pattern data. The number of
errors injected is set using the Test-Pattern Error Injection Register (0x0F), Table 28 on page 44.
If error injection is required, the process should start by setting up the test-pattern generator using steps 1—3 in
the T est-Pattern Generation section on page 28. In order to start injecting errors into the outgoing test pattern, write
the T est-Pattern Error Injection Register (0x0F), Table 28 on page 44 with the number of errors desired. When all of
the errors have been injected into the outgoing data stream, the interrupt status bit BEI (bit 0) will be set in the
Interrupt Status Register (0x07), Table 20 on page 40. Errors will be injected at the rate of one per time slot. Test
Command Register (0x09), Table 22 on page 42 will be cleared to 0 when BEI is set.
Error Checking
Errors are checked on time slots marked for test-pattern data once the checker has locked onto the test pattern.
Every time an error is detected, the ERD (bit 3) interrupt status bit is set and the test-pattern error counter register
contents are incremented. There are two registers T est-Pattern Error Counter (Byte 0) (0x10), T able 29 on page 45
and Test-Pattern Error Counter (Byte 1) (0x11), Table 30 on page 45, that are used to track the number of errors
detected on incoming test patterns.
The error counter registers are reset after both have been read. In order to ensure that the correct value is read
from these registers, byte 0 must be read first followed by byte 1. This action will latch the counter value and allow
the counter logic to be reset and then continue recording.
The boundary scan (BS) is a test aid for chip, module, and system testing. The key aspects of BS are as follows:
1. Testing the connections between ICs on a particular board.
2. Observation of signals to the IC pins during normal operating functions.
3. Controlling the built-in self-test (BIST) of an IC. TTSI4K32T does not support BS-BIST.
Designed according to the
test access port (TAP). The TAP is made up of four signal pins assigned solely for test purposes. The fifth test pin
ensures that the test logic is initialized asynchronously . The BS test logic also comprises a 16-state TAP controller ,
an instruction register with a decoder, and several test data registers (BS register, BYPASS register, and IDCODE
register). The main component is the BS register that links all the chip pins to a shift register by means of special
logic cells. The test logic is designed in such a way that it is operated independently of the application logic of the
TTSI4K32T (the mode multiplexer of the BS output cells may be shared). Figure 14 illustrates the block diagram of
the TTSI4K32T’s BS test logic.
IEEE
Std. 1149.1-1990 standard, the BS test logic consists of a defined interface: the
BOUNDARY-SCAN REGISTER
TDI
TRST
TMS
TCK
CHIP KERNEL
MUX
OUT
TDO
IN
CONTROLLER
(UNAFFECTED BY BOUNDARY-SCAN TEST)
IDCODE REGISTER
BYPASS REGISTER
INSTRUCTION REGISTER
TAP
INSTRUCTION
DECODER
5-3923(F)r.4
Figure 14. Block Diagram of the TTSI4K32T's Boundary-Scan Test Logic
30Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
JTAG Boundary-Scan Specification
(continued)
Test Access Port Controller
The test access port controller is a synchronous sequence controller with 16 states. The state changes are preset
by the TMS, TCK, and TRST
TCK edge rises. Figure 15 shows the TAP controller state diagram.
1
0
signals and by the previous state. The state changes always take place when the
TRST = 0
TEST LOGIC
RESET
0
RUN TEST/
IDLE
CAPTURE DR
1
SELECT DR
0
0
SHIFT DR
1
1
0
1
SELECT IR
0
CAPTURE IR
0
SHIFT IR
1
1
0
EXIT1 DR
0
PAUSE DR
0
1
0
EXIT2 DR
1
UPDATE DR
10
0
EXIT1 IR
PAUSE IR
EXIT2 IR
UPDATE IR
10
11
0
0
1
1
5-3924(F)r.5
Figure 15. BS TAP Controller State Diagram
The value shown next to each state transition in Figure 15 represents the signal present at TMS at the time of a rising edge at TCK.
The description of the TAP controller states is given in
IEEE
Std. 1149.1-1990 Section 5.1.2 and is reproduced in
Table 9. TAP Controller States in the Data Register Branch
NameDescription
TEST LOGIC RESETThe BS logic is switched in such a way that normal operation of the ASIC is
adjusted. The IDCODE instruction is initialized by TEST LOGIC RESET.
Irrespective of the initial state, the TAP controller has achieved TEST LOGIC
RESET after five control pulses at the latest when TMS = 1. The TAP controller
then remains in this state. This state is also achieved when TRST
RUN TEST/IDLEUsing the appropriate instructions, this state can activate circuit parts or initiate
a test. All of the registers remain in their present state if other instructions are
used.
SELECT DRThis state is used for branching to the test data register control.
CAPTURE DRThe test data is loaded in the test data register parallel to the rising edge of TCK
in this state.
SHIFT DRThe test data is clocked by the test data register serially to the rising edge of TCK
in the state. The TDO output driver is active.
EXIT (1/2) DRThis temporary state causes a branch to a subsequent state.
PAUSE DRThe input and output of test data can be interrupted in this state.
UPDATE DRThe test data is clocked into the second stage of the test data register parallel to
the falling edge of TCK in this state.
(continued)
(continued)
= 0.
Table 10. TAP Controller States in the Instruction Register Branch
NameDescription
SELECT IRThis state is used for branching to the instruction register control.
CAPTURE IRThe instruction code 0001 is loaded in the first stage of the instruction register
parallel to the rising edge of TCK in this state.
SHIFT IRThe instructions are clocked into the instruction register serially to the rising edge
of TCK in the state. The TDO output driver is active.
EXIT (1/2) IRThis temporary state causes a branch to a subsequent state.
PAUSE IRThe input and output of instructions can be interrupted in this state.
UPDATE IRThe instruction is clocked into the second stage of the instruction register parallel
to the falling edge of TCK in this state.
32Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
JTAG Boundary-Scan Specification
(continued)
Instruction Register
The instruction register (IR) is 4 bits in length. Table 11 shows the BS instructions implemented by the TTSI4K32T.
The instructions not supported in TTSI4K32T are INTEST, RUNBIST, and TOGGLE. A fixed binary 0001 pattern
(the 1 into the least significant bit) is loaded into the IR in the CAPTURE IR controller state. The IDCODE instruction (binary 0001) is loaded into the IR during the test-logic-reset controller state and at powerup.
ModeFunctionOutput Defined Via
BS Register
connections
Core Logic
Register
The following is an explanation of the instructions supported by TTSI4K32T and their effect on the devices' pins.
EXTEST:
This instruction enables the path cells, the pins of the ICs, and the connections between ASICs to be tested via the
circuit board. The test data can be loaded in the chosen position of the BS register by means of the SAMPLE/PRELOAD instruction. The EXTEST instruction selects the BS register as the test data register. The data at the function inputs is clocked into the BS register on the rising edge of TCK in the CAPTURE DR state. The contents of the
BS register can be clocked out via TDO in the SHIFT DR state. The value of the function outputs is solely determined by the contents of the data clocked into the BS register and only changes in the UPDA TE DR state on the
falling edge of TCK.
IDCODE:
Information regarding the manufacturer’s ID for Lucent, the IC number, and the version number can be read out
serially by means of the IDCODE instruction. The IDCODE register is selected, and the BS register is set to normal
mode in the UPDATE IR state. The IDCODE is loaded at the rising edge of TCK in the CAPTURE DR state. The
IDCODE register is read out via TDO in the SHIFT DR state.
HIGHZ:
All 3-statable outputs are forced to a high-impedance state, and all bidirectional ports are forced to an input state
by means of the HIGHZ instruction. The impedance of the outputs is set to high in the UPDATE IR state. The function outputs are only determined in accordance with another instruction if a different instruction becomes active in
the UPDATE IR state. The BYPASS register is selected as the test data register. The HIGHZ instruction is implemented in a similar manner to that used for the BYPASS instruction.
SAMPLE/PRELOAD:
The SAMPLE/PRELOAD instruction enables all the input and output pins to be sampled during operation (SAM-
PLE) and the result to be output via the shift chain. This instruction does not impair the internal logic functions.
Defined values can be serially loaded in the BS cells via TDI while the data is being output (PRELOAD).
BYPASS:
This instruction selects the BYPASS register. A minimal shift path exists between TDI and TDO. The BYPASS reg-
ister is selected after the UPDATE IR. The BS register is in normal mode. A 0 is clocked into the BYPASS register
during CAPTURE DR state. Data can be shifted by the BYPASS register during SHIFT DR. The contents of the BS
register do not change in the UPDATE DR state. Please note that a 0 that was loaded during CAPTURE DR
appears first when the data is being read out.
(continued)
(continued)
Boundary-Scan Register
The boundary-scan register is a shift register, whereby one or more BS cells are assigned to every digital
TTSI4K32T pin. The TTSI4K32T’s boundary-scan register bit-to-pin assignment is defined in the BSDL file, which
is available upon request.
BYPASS Register
The BYPASS register is a one-stage shift register that enables the shift chain to be reduced to one stage in the
TTSI4K32T.
IDCODE Register
The IDCODE register identifies the TTSI4K32T by means of a parallel, loadable, 32-bit shift register. The code is
loaded on the rising edge of TCK in the CAPTURE DR state. The contents of this register is indicated in the BSDL
file.
3-State Procedures
The 3-state input participates in the boundary scan. It has a BS cell, but buffer blocking via this input is suppressed
for the EXTEST instruction. The 3-state input is regarded as a signal input that is to participate in the connection
test during EXTEST. The buffer blocking function should not be active during EXTEST to ensure that the update
pattern at the TTSI4K32T outputs does not become corrupted.
34Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Register Architecture
Table 12 is an overview of the register architecture. The table is a summary of the register function and address.
Complete detail of each register is given in the following sections.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Configuration Register Architecture
: All registers’ bits default to 0 upon reset, unless noted otherwise.
Note
All TDM highway data, which is stored in the TSI, will have the following convention. Bit 7 is first transmitted
and first received; bit zero is last transmitted and last received. This convention applies to the data read
from the data store, the host data transmitted via the connection store, and any other configuration register
which stores highway data, such as the idle code registers and the test-pattern generator data register.
Table 13. General Command Register (0x00)
BitSymbolName/Description
7CSV
6ED
Chip Select Valid.
cessor interface mode only. When this bit is programmed to be 1, the chip select input
pin is sampl ed w hen AS
active.
External Drivers.
indicates that no external buffers are being used; therefore, the TXD pins will become
3-stated for time slots that are programmed as such. A 1 indicates that the TXD output
highways are connected to external drivers; thus, the TXD pins will always be driven
to prevent floating nodes at the inputs of the external drivers. The TXOE[0—31] outputs always reflect the high-impedance status of the corresponding TXD[0—31] highways, regardless of the ED bit setting. The only exception to this is when TEST
asserted, which 3-states all outputs.
This bit is valid while the TTSI4K32T is in synchronous micropro-
is active. When 0, chip select is latched one PCLK after AS is
Used to select the use of external drivers on transmit highways. A 0
is
See Table 39, Transmit Highway 3-State Options, on page 50 for other methods of
3-stating the transmit highways.
5—
4INTOE
3INTP
2FSP
1FSSE
0GXE
Reserved.
Interrupt Output Enable.
be driven based on the status of the internal interrupts and their corresponding individ-
ual mask bits. When 0, the output will remain 3-stated.
Interrupt Polarity.
A 1 selects an active-low interrupt output (INT
output (INT), and is the default polarity.
Frame Sync Polarity.
which designates the beginning of the frame. A 1 selects an active-high frame syn-
chronization (FSYNC). A 0 selects an active-low frame synchronization (FSYNC
Frame Sync Sample Edge.
used to sample the frame synchronization input. A 1 selects the rising edge; and a 0
selects the falling edge of CK.
Global Transmit Enable.
defaults to 0 so that all outputs can be held in a high-impedance state until they have
been configured and individually enabled.
For other methods of 3-stating transmit highways, see Table 39, Transmit Highway
3-State Options, on page 50.
Read as 0.
This bit, when set to a 1, enables the INT output signal to
This bit defines the polarity of INT, as output from the TTSI4K32T.
). A 0 selects an active-high interrupt
This bit defines the polarity of FSYNC, as sampled by CK,
).
This bit selects the clock edge of the CK input that is
When 0, all 32 transmit highways are 3-stated. GXE
similar to the RESET
tialized to their default values except the software reset register. A 0 must be
written to this bit in order to clear and release the software reset. The microprocessor interface will not be affected by the software reset, and the write to this bit
will terminate normally.
Run BIST.
ory blocks (i.e., the data and connection stores). This bit must be cleared by writing a 0 when BIST is complete. That event is indicated via the BIST complete
(BC) bit in the interrupt status register, as well as the BIST done (BD) bit in the
BIST command register. W riting a 0 to this bit position will also clear the BD bit. A
software reset should be performed after the BIST testing sequence is complete.
BIST Done (Read Only).
bit is used for polling to determine the completion of the BIST test. The real-time
duration of the TSI BIST test is 2.8 seconds. This bit will remain set to a 1 reflecting the fact that the BIST is complete until the RB bit is written to a 0.
BIST Pass
results. A 0 indicates that no errors were detected.
Reserved.
Read as 0.
Writing a 1 to this bit begins the built-in self-test for all internal mem-
/Fail (Read Only).
Read as 0.
(continued)
Writing a 1 to this bit resets the chip. This bit has a function
pin. When set to 1, all registers and control logic will be ini-
This bit indicates when the BIST test is complete. This
This bit indicates the status of the BIST test
The BIST test sequence is performed as follows:
1.Set RB (bit 7) in the BIST command register to 1 in order to initiate the internal BIST test.
2.Wait for the BIST complete (BC) (bit 1 of the interrupt status register) interrupt to occur via the interrupt status
register, if it is not masked via the interrupt mask register MASKBC bit (bit 1). Alternatively , the host can poll the
BD bit in the BIST command register which will also indicate the completion of BIST.
3.Once the BIST interrupt occurs or the BD bit is set, the BPF bit in the BIST command register will reflect the
BIST pass/fail result. A BPF set to 0 indicates a pass.
4.Set RB (bit 7) in the BIST command register to a 0 in order to end the internal BIST test.
5.Issue a software reset via the SR bit in the software reset register.
During BIST, the TTSI4K32T will corrupt traffic and the contents of the connection store memory. The TTSI4K32T
should, therefore, be taken off-line prior to running BIST and reprogrammed afterwards.
38Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Configuration Register Architecture
Table 16. Idle Code 1 Register (0x03)
BitSymbolName/Description
7—0IC1
Table 17. Idle Code 2 Register (0x04)
BitS ymbolName/Description
7—0IC2
Table 18. Idle Code 3 Register (0x05)
BitS ymbolName/Description
7—0IC3
Idle Code 1[7—0].
outgoing time slot marked for idle code 1 transmission. Idle code transmission is
enabled via the time-slot data select mode bits. See Table 43, Connection Store
Memory (Byte 1), on page 52.
Idle Code 2[7—0].
outgoing time slot marked for idle code 2 transmission. Idle code transmission is
enabled via the time-slot data select mode bits. See Table 43, Connection Store
Memory (Byte 1), on page 52.
Idle Code 3[7—0].
outgoing time slot marked for idle code 3 transmission. Idle code transmission is
enabled via the time-slot data select mode bits. See Table 43, Connection Store
Memory (Byte 1), on page 52.
(continued)
This register is used to identify the data to be sent on any
This register is used to identify the data to be sent on any
This register is used to identify the data to be sent on any
Table 19. Global Interrupt Mask Register (0x06)
BitS ymbolName/Description
7—1—
0GIE
Reserved.
Global Interrupt Enable.
asserted as a result of the possible interrupt conditions. This is in addition to
the mask bits in the interrupt mask register. When 0, the INT output is blocked
independent of the programming of the interrupt mask register. When 1, the
INT output is enabled and will be asserted based on the interrupt status and
mask bits.
Read as 0.
This bit must be written to a 1 in order for INT to be
sync has occurred. This error could be a result of a missing FSYNC or a misaligned FSYNC.
Test Pattern Detected.
checker. When TPD = 0, the test-pattern checker
selected test pattern. When TPD = 1, the test-pattern checker
selected test pattern. T est-pattern data must be error-free for 32 time slots before
it is considered detected. If 32 or more time slots are selected for test-pattern
checking, this event could occur within one 125 µs frame. If only two time slots
are selected for test-pattern checking, then the test pattern will be detected after
16 frames.
Reserved.
Error Detected.
test pattern once the test pattern has first been detected.
Reserved.
BIST Complete.
complete.
Bit Errors Inserted.
insert bit errors into the outgoing test pattern is complete.
(continued)
Read as 0.
When set to 1, this bit indicates that an error related to frame
The TPD bit indicates the state of the test-pattern
Read as 0 or 1.
This bit is set to 1 each time an error has been detected in the
Read as 0.
When set to 1, this status bit indicates that the BIST sequence is
When set to 1, this status bit indicates that the request to
has not
yet located the
located the
has
This register is clear on read. Once the status bits are read, they will remain cleared until the next interrupt event
occurs. The interrupt mask register in combination with the global interrupt enable GIE (bit 0) in the global interrupt
mask register determines when the INT pin gets asserted when an interrupt status bit gets set. In general, the interrupt status register bits will update regardless of the mask bits. The exception to this is the FSERR bit, which will
not be set if the corresponding mask bit is set.
40Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Configuration Register Architecture
Table 21. Interrupt Mask Register (0x08)
BitSymbolName/Description
7—
6MASKFS
5MASKTPD
4—
3MASKERD
2—
1MASKBC
0MASKBEI
Reserved.
Mask Frame Sync Error Interrupt.
an interrupt as a result of a frame sync error. Resets to a 1, which prevents the
status bit from generating an interrupt. Setting this bit to a 1 also prevents the
detection of a frame sync error and, thus, the setting of the FSERR bit in the
interrupt status register. This is done to prevent an unintended interrupt at the
first FSYNC pulse after the reset sequence.
Mask Test-Pattern Detection Interrupt.
tion of an interrupt as a result of a test-pattern detection. Resets to a 1, which
prevents the status bit from generating an interrupt.
Reserved.
Mask Error Detected Interrupt.
interrupt as a result of a single bit error detected in the incoming test pattern.
Resets to a 1, which prevents the status bit from generating an interrupt.
Reserved.
Mask BIST Complete Interrupt.
interrupt as a result of completing the memory BIST. Resets to a 1, which prevents the status bit from generating an interrupt.
Mask Bit Errors Inserted Interrupt.
an interrupt as a result of completing the insertion of all requested bit errors.
Resets to a 1, which prevents the status bit from generating an interrupt.
(continued)
Read as 0.
Read as 1. Always write a 1 to this bit when writing this register.
Set this bit to a 1 to mask the generation of an
Read as 1. Always write a 1 to this bit when writing this register.
Set this bit to a 1 to mask the generation of an
Set this bit to a 1 to mask the generation of
Set this bit to a 1 to mask the genera-
Set this bit to a 1 to ma s k th e ge n er at i on of
tor to start generating a test pattern based on the pattern indicated in the testpattern style register. Writing a 0 to this register will stop the test-pattern generation and provide the opportunity to change the test-pattern style.
Start Test-Pattern Checker.
start locking on to a test pattern based on the pattern indicated in the testpattern style register. Writing a 0 to this register will stop the test-pattern checking and provide the opportunity to change the test-pattern style.
Test-Pattern Generator Highway Data Rate.
the highway data rate of the transmit highway selected for test-pattern generation. It must match the Tx highway data rate which was set in transmit highway
configuration register (byte 2), HDR[1—0] bits. The transmit highway selection
for test-pattern generation is done using the connection store. Only one highway
at a time can be involved with test-pattern generation. Test-pattern generation
and checking does not affect the operation of other time slots or highways.
highway data rate of the receive highway selected for test-pattern checking. It
must match the Rx highway data rate which was set in receive highway configuration register (byte 2), HDR[1—0] bits. The transmit highway selection for testpattern generation is done using the test-pattern checker highway register. Only
one highway at a time can be involved with test-pattern checking. Test-pattern
generation and checking does not affect the operation of other time slots or highways.
(continued)
Writing a 1 to this register will cause the genera-
Writing a 1 to this register will cause the checker to
slot in the input highway to which the test-pattern checker is connected. All contiguous time slots that lie between the lower and upper time-slot boundaries
inclusive are monitored for the test pattern. The range of time slots that can be
monitored is from 1 time slot to the entire span (32, 64, and 128 time slots for a
2.048 Mbits/s, 4.096 Mbits/s, 8.192 Mbits/s highway, respectively). If one time
slot is to be monitored, then CKRUP and CKRLOW should be set to the same
value.
(continued)
These 5 bits determine the receive highway to
These 7 bit s de ter mi ne t he u pper ti me
BitSymbolName/Description
7—
6—0CKRLOW
[6—0]
Table 27. Test-Pattern Checker Data Register (0x0E)
slot in the input highway to which the test-pattern checker is connected. All contiguous time slots that lie between the lower and upper time-slot boundaries
inclusive are monitored for the test pattern. The range of time slots that can be
monitored is from 1 time slot to the entire span (32, 64, and 128 time slots for a
2.048 Mbits/s, 4.096 Mbits/s, 8.192 Mbits/s highway, respectively). If one time
slot is to be monitored, then CKRUP and CKRLOW should be set to the same
value.
Checker Test Pattern[7—0].
when the fixed mode is programmed into the test-pattern style register.
Bit Error Count[7—0].
errors that are to be injected into the outgoing test pattern (QRSS, PRBS, or
fixed user-defined byte). This register can be programmed to inject up to 255 bit
errors. The BEI bit in the interrupt status register will indicate when all of the
errors have been injected. BEC[7—0] will automatically be reset when BEI is
set. In order to send out additional errors, BEC[7—0] should be rewritten. Errors
are injected at the rate of one per time slot.
These 7 bits determine the lower time
The data written here will be used for comparison
This register is used to indicate the number of single bit
44Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
The error counter will be incremented each time a bit error is detected by the pattern checker.
In order to ensure that the correct value is read from these registers, byte 0 must be read first followed by
byte 1. This action will latch the error counter value and allow the counter to be reset and continue recording
as time proceeds.
Table 31. Test-Pattern Generator Data Register (0x12)
BitSymbolName/Description
7—0GTP[7—0]
Generator Test Pattern[7—0].
if the fixed data test-pattern mode is selected in the test-pattern style register.
Least significant bits of 16-bit error counter. See note
Most significant bits of 16-bit error counter. See note
The data written here will be sent out repeatedly
Table 32. Version Register (0x13)
*
BitSymbolName/Description
7—2—
1—0VER[1—0]
* Read-only register.
† Reading a 00 from this register indicates version number 1.0.
an outgoing frame by the indicated number of bit times. If no bit offsets are
required, these bits should be set to 000. The following list shows the effect of
setting these bits.
000 = no bit offset
001 = 1-bit offset
010 = 2-bit offset
. . .
111 = 7-bit offset
Bit periods are relative to the highway data rate set for each highway.
Note:
XTSOFF, XBITOFF, and XFBOFF are used in conjunction to define the start of
the outgoing frame. The values are added together to position the sampling of
time slot 0, bit 0 for each highway.
Transmit Highway Fractional Bit Offset[1—0].
beginning of an outgoing frame by the indicated number of fractional bit times. If
no fractional bit offsets are required, these bits should be set to 00. The following
list shows the effect of these bits.
Bit periods are relative to the highway data rate set for each highway.
Note:
XTSOFF, XBITOFF, and XFBOFF are used in conjunction to define the start of
the outgoing frame. The values are added together to position the sampling of
time slot 0, bit 0 for each highway.
Reserved.
Must be written to 00.
46Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
beginning of an outgoing frame by the indicated number of time slots (bytes). If
no time-slot offsetting is required, these bits should be set to zero. The following
table shows the range of offsets for the different highway data rates.
Highway Data Rate
2.048 Mbits/s 0—31
4.096 Mbits/s 0—63
8.192 Mbits/s 0—127
A time slot is always 8 bits. A bit period is relative to the highway data rate
Note:
set for each highway.
XTSOFF, XBITOFF, and XFBOFF are used in conjunction to define the start of
the outgoing frame. The values are added together to position the transmission
of time slot 0, bit 0.
(continued)
Read as 0.
Time-Slot Offset Range
XTSOFF is used to offset the
*
BitSymbolName/Description
7—3—
2XE
1—0HDR[1—0]
* i = the transmit highway number.
: During CK input interruptions (e.g., clock switching), the transmit highways should be 3-stated by clearing
Note
the GXE (bit 0) of the general command register. The highways can be enabled by writing a 1 to the GXE bit
once the PLL has regained lock (250 µs later).
Reserved.
Transmit Highway 3-State Enable
impedance when this bit is 0 (default after reset). When this bit is set to 1, the
output driver is enabled. The effect of this bit is dependent on the status of the
external drive bit of the general command register. See Table 13, General Command Register (0x00), on page 37 for details. For other methods of 3-stating
transmit highways, see Table 39, Transmit Highway 3-State Options, on page
an incoming frame by the indicated number of bit times. If no bit offsets are
required, these bits should be set to 000. The following list shows the effect of
setting these bits.
000 = no bit offset
001 = 1-bit offset
010 = 2-bit offset
. . .
111 = 7-bit offset
Bit periods are relative to the highway data rate set for each highway.
Note:
RTSOFF, RBITOFF, and RFBOFF are used in conjunction to define the start of
the incoming frame. The values are added together to position the sampling of
time slot 0, bit 0 for each highway.
Receive Highway Fractional Bit Offset[1—0].
beginning of an incoming frame by the indicated number of fractional bit times. If
no fractional bit offsets are required, these bits should be set to 00. The following
list shows the effect of these bits.
Bit periods are relative to the highway data rate set for each highway.
Note:
RTSOFF, RBITOFF, and RFBOFF are used in conjunction to define the start of
the incoming frame. The values are added together to position the sampling of
time slot 0, bit 0 for each highway.
Reserved.
(Read/Write) Must be written to 00.
48Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
ning of an incoming frame by the indicated number of time slots (bytes). If no
time-slot offsetting is required, these bits should be set to zero. The following
table shows the range of offsets for the different highway data rates.
Highway Data Rate
2.048 Mbits/s 0—31
4.096 Mbits/s 0—63
8.192 Mbits/s 0—127
A time slot is always 8 bits. A bit period is relative to the highway data rate
Note:
set for each highway.
RTSOFF, RBITOFF, and RFBOFF are used in conjunction to define the start of
the incoming frame. The values are added together to position the sampling of
time slot 0, bit 0.
(continued)
Read as 0.
Time-Slot Offset Range
*
RTSOFF is used to offset the begin-
*
BitSymbolName/Description
7—3—
2LC
1—0HDR[1—0]
* i = the receive highway number.
Reserved.
Loopback Control.
highway to the corresponding RXD highway. When set to 1, the TXD highway as
input to this RXD highway. The transmit highway involved will be internally
looped back to the matching receive highway so that the TXD[i] output is now the
input to RXD[i]. When a particular highway is in this mode, the receive highway
offset must be 1/2-bit greater than the corresponding transmit highway offset.
When LC is cleared to 0, the RXD pin is the source of highway data (default).
Receive Highway Data Rate[1—0].
HDR1
Read as 0.
This bit is used to control the internal loopback of the TXD
There are several ways of 3-stating the transmit highways:
(active-low) is the input pin that 3-states all outputs and bidirectional pins of the device.
TEST
GXE (bit 0) (active-high) is the global transmit enable bit in the general command register. It applies to all transmit
highways.
XE (bit 2) (active-high) is the transmit highway 3-state enable bit in the transmit highway configuration register
(byte 2). There is a separate XE bit for each one of the 32 transmit highways.
ED (bit 6) (active-high) is the external drivers bit in the general command register. This bit applies to all the transmit
highways. It affects the 3-stating of the transmit highways. Time slots that are selected to be 3-stated, by setting
the TSDSM[2 —0] bi ts to 0x 7 in byt e 2 of the co nnect ion st ore, wi ll be dri ven with rand om dat a if ED = 1. Ot herwi se,
these time slots will be 3-stated.
Table 39. Transmit Highway 3-State Options
TEST
(Input
Pin)
GXE
(Cfg
Bit)
ED
(Cfg
Bit)
XE for
Transmit
Highway [i]
(Cfg Bit)
0XXX
100X
101X
1100
1101
1110
1111
according to connection store pro-
TXD[i] is driven with random data.TXOE[i] = 0.
TXD[i] = 0 or 1 reflecting the correct
transmit data. Time slots which are
selected for high-impedance mode
TXD[0—31] PinsTXOE[0—31] Pins
All high impedance.All high impedance.
All high impedance.All 0.
All driven with random data.All 0.
TXD[i] = high impedance.TXOE[i] = 0.
TXD[i] = 0, 1, or high impedance
gramming.
via the connection store will be
driven with random data and not
3-stated.
TXOE[i] = 0 or 1, representing high-imped-
ance state according to connection store
programming.
TXOE[i] = 0 or 1, representing high-imped-
ance state according to connection store
programming.
50Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Data Store Memory
Microprocessor access to the incoming highway data is provided by directly reading the data store memory. Each
one of the time slots is addressable by constructing the address in the following way
address space will occur immediately. Microprocessor writes to this address space will not change the contents of
the data store. If user data is to be sent out on a particular time slot, the host data substitution mode in the connection store should be used.
Table 40. Address Scheme for Data Store Memory
.
Microprocessor reads to this
Data Store
Memory Address
To illustrate the addressing scheme, consider the following examples:
To read the data received in time slot 7 on RXD6, the following address is used to access the TSI data store mem-
ory location.
Note:
All TDM highway data which is stored in the TSI will have the following convention. The most significant bit
of a byte is first transmitted and first received, the least significant bit is last transmitted and last received.
This convention applies to the data read from the data store, the host data transmitted via the connection
store, and any other configuration register that stores highway data.
14131211109876543210
010Receive Highway
Number (0—31)
A[14—0] = 010_00110_0000111 = 0x2307
Receive Time-Slot Address
(0—127)
Connection Store Memory
The connection store memory is primarily used to set up the switching matrix and selects the transmit data source
for each one of the outgoing time slots. There are two connection store byte locations associated with each one of
the outgoing time slots. The address for each of the corresponding connection store memory locations is constructed in the following way.
Table 41. Address Scheme for Connection Store Memory
Connection Store
Memory Address
If any particular transmit highway is not programmed to use the total available bandwidth (8.192 Mbits/s), then the
connection store memory locations representing the unused time slots are not used. For example, assume highway 7 is set for a highway data rate of 4.096 Mbits/s. This translates to a total of 64 time slots being transmitted on
highway 7. In that case, addresses A[14—0] = 0x4700—0x477F must be set. Addresses A[14—0] = 0x4780—
0x47FF are irrelevant for a 4.096 Mbits/s highway and need not be set.
The connection store memory does not have a default state. Therefore, after powerup, the relevant locations in the
connection store must be programmed. However, the connection store contents are not affected by a software or
hardware reset of the TTSI4K32T.
Receive Time-Slot Address[6—0]/Host Substituted Data [7—0].
latency or frame-integrity time-slot data select modes are selected for the particular transmit time slot being configured, then these bits are used to indicate the
receive time-slot address from which the transmit time-slot data is sourced. Bit 7
should be set to 0.
If the host data substitution mode is selected for the particular transmit time slot
being configured, then these 8 bits will represent the data byte to be transmitted.
These bits are not valid for time-slot data select modes 3—7.
Time-Slot Data Select Mode[2—0]
000Low-latency mode.
001Fram e- int egri ty mod e.
010Host data substitution mode.
011Idle code 1 substitution mode.
100Idle code 2 substitution mode.
101Idle code 3 substitution mode.
110Test-pattern substitution mode—test pattern is
111High-impedance mode.
Receive Highway Number.
outgoing time-slot data is sourced. These bits are only valid for time-slot data
select modes 0 and 1.
If low-
selected via test-pattern style register.
Used to select the receive highway from which the
To illustrate the connection store programming scheme, consider the following example:
To configure the transmission of time slot 7 on TXD6, the following addresses are used to access the relevant TSI
Now, if it is desired to send Rx time slot 4 from RXD3 to time slot 7 on TXD6 in frame integrity mode, then the following data should be written to the above addresses.
Data byte 0 = 0_0000100 = 0x04
Data byte 1 = 001_00011 = 0x23
Thus, to map Rx time slot 4 from RXD3 to Tx time slot 7 on TXD6, in frame integrity mode, the following two TSI
writes must be performed.
Write location 0x460E with 0x04
Write location 0x460F with 0x23
52Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Connection Store Memory
TSDSM[5—0] (bits 7—5) of byte 1 of the connection store select the source of data for each of the time slots being
transmitted by the TTSI4K32T. The configuration can be divided into three groups.
Group 1Low-Latency Mode.
the data store based on the programming of TSA[6—0] (bits 6—0) of byte 0 and RXHWY[4—0]
(bits 4—0) of byte 1. Bit 7 of byte 0 is ignored. When each of the individual transmit time slots are
retrieved f rom the dat a sto re m emo ry for tr ansm issi on, t he most rece nt c opy of th e re ceiv e ti me sl ot wi ll
be fetched resulting in a latency that never exceeds 134 µs. This is the maximum latency for lowlatency mode independent of highway configurations (e.g., highway speed, clock speed, offsets, etc.).
Refer to the Low-Latency and Frame-Integrity Modes section on page 24 for a detailed description of
the latency calculation.
Frame-Integrity Mode.
from the data store based on the programming of TSA[6—0] (bits 6—0) of byte 0 and RXHWY[4—0]
(bits 4—0) of byte 1. Bit 7 of byte 0 is ignored. Any number of time slots from any number of transmit
highways can be marked for frame integrity. When each of the individual transmit time slots marked for
frame integrity are retrieved from the data-store memory for transmission, the internal controller
ensures that they are chosen from a receive frame which has already been entirely stored in the data
store, thereby ensuring frame integrity.
Refer to the Low-Latency and Frame-Integrity Modes section on page 24 for a detailed description of
the actual latency incurred through the device.
Group 2Host-Data Substitution Mode.
repeatedly onto any or all of the 4096 transmit time slots; however, the data to be substituted is stored
in HSD[7—0] (bits 7—0) of byte 0 for each transmit time slot. RXHWY[4—0] (bits 4—0) of byte 1 are
ignored in this mode. Host-data mode can be used to customize the data for each of the 4096 transmit
time slots. When a time slot is configured for host-data substitution mode, the data written to byte 0 of
the connection store will have the following convention. Bit 7 is first transmitted, and bit 0 is last transmitted.
(continued)
For the time slots marked as low latency, the transmit data will be retrieved from
For the time slots marked as frame integrity, the transmit data will be retrieved
This mode also provides the means to transmit host-supplied data
Idle-Code Substitution Mode.
mit microprocessor data repeatedly onto any or all of the 4096 transmit time slots. Three idle-code registers (separate from the connection store memory) provide the capability to repeatedly broadcast three
different programmed values to any or all time slots set for idle-code substitution mode. When programming idle-code substitution mode, only the TSDSM[2—0] (bits 7—5) of byte 1 for all of the transmit time
slots involved needs to be written. Byte 0 and RXHWY[4—0] (bits 4—0) of byte 1 are both ignored.
Test-Pattern Substitution Mode.
than use the receive time slots being stored in the data store. Since the test-pattern selection is done
outside of the connection store, only TSDSM[2—0] (bits 7—5) of byte 1 for each of the time slots
involved needs to be programmed. Byte 0 and RXHWY[4—0] (bits 4—0) of byte 1 are both ignored.
The test-pattern selection and usage rules are described in the Test-Pattern Generation section on
page 28.
Group 3High-Impedance Mode.
ual basis. For example, consider the case where an 8.192 Mbits/s highway is shared by four devices,
each having one-fourth of the total bandwidth. If the TTSI4K32T were allocated time slots 64—95, then
high-impedance mode would be set for time slots 0—63 and 96—127. Time slots 64—95 could be set
to any combination of the eight possible modes. When programming the high-impedance mode, only
TSDSM[2—0] (bits 7—5) of byte 1 for all of the transmit time slots involved needs to be written. Connection store byte 0 and RXHWY[4—0] (bits 4—0) of byte 1 are both ignored.
These three idle-code substitution modes provide the means to trans-
This mode is also used to substitute alternative transmit data rather
This mode is used to 3-state any of the 4096 transmit time slots on an individ-
Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are absolute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess
of those given in the operations sections of this data sheet. Exposure to absolute maximum ratings for extended
periods can adversely affect device reliability. External leads can be safely soldered or bonded at temperatures up
to 300 °C.
ParameterSymbolMinMaxUnit
Storage TemperatureT
Voltage on Any Pin with Respect to GroundV
Power DissipationP
* This maximum rating only applies when the device is powered up with VDD.
stg
IN
–65125°C
–0.55.8*V
D
—460mW
Operating Conditions
ParameterSymbolMinMaxUnit
Power SupplyV
Low-level Input VoltageV
High-level Input VoltageV
Ambient Operating Temperature RangeT
DD
IL
IH
A
2.973.63V
—0.8V
2.15.8V
–4085°C
Handling Precautions
Although protection circuitry has been designed into this device, proper precautions should be taken to avoid exposure to electrostatic discharge (ESD) during handling and mounting. Lucent employs a human-body model (HBM)
and a charged-device model (CDM) for ESD-susceptibility testing and protection design evaluation. ESD voltage
thresholds are dependent on the circuit parameters used to define the model. No industry-wide standard has been
adopted for the CDM. However, a standard HBM (resistance = 1500 Ω, capacitance = 100 pF) is widely used and,
therefore, can be used for comparison. The HBM ESD threshold presented here was obtained by using these circuit parameters:
Human-Body Model ESD Threshold
DeviceVoltage
TTSI4K32T>1000 V
54Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Electrical Characteristics
TA = –40 °C to +85 °C; VDD = 3.3 V ± 10%; VSS = 0 V
Figure 16. Asynchronous Read Cycle Timing Using DT Handshake
A[14—0]
R/W
CS
AS
t1
DS
HIGH IMPEDANCE
DT
t6
(continued)
READ ADDRESS
t2
t3
t5
t4
t4
t8
READ DATA
5-7063(F)r.2
WRITE ADDRESS
t2
t3
t5
t4
t4
t7
D[7—0]
WRITE DATA
5-7064(F)r.2
Figure 17. Asynchronous Write Cycle Timing Using DT Handshake
Table 45. Asynchronous Read and Write Interface Timing Using DT
Handshake
SymbolDescriptionMinMaxUnit
t1A[14—0] or R/W
t2A[14—0] or R/W
t3CS
t4DT
t5DT
Hold from AS or DS4*—ns
Output Delay from AS or DS (CL = 50 pF)3*8*ns
or D[7—0] High-impedance from CS (CL = 50 pF)—8.5*ns
t6D[7—0] Input Setup to DS
t7D[7—0] Input Hold from DS
t8D[7—0] Output Setup Prior to DT
*CS asynchronously controls the output enable of D[7—0] and DT. The delay from CS to the output enable of DT is equivalent to the delay
from AS
or DS to DT . Therefore, in order to guarantee that DT is driven high before being 3-stated, a CS hold time is required (t3). If this timing cannot be met, then there are two options. One, disconnect DT
be completed by the device 183 ns after the start of the cycle, which is defined by CS
use an external pull-up on DT
Setup to AS0—ns
Hold from AS0—ns
(CL = 50 pF)0—ns
(CL = 50 pF)0—ns
Output (CL = 50 pF)0—ns
and rely on wait-states to terminate the cycle. The read or write cycle will
, AS, and DS all being active. The second option is to
to pull DT high within the timing requirements of the micropr ocessor.
56Lucent Technologies Inc.
Data SheetTTSI4K32T
June 20004096-Channel, 32-Highway Time-Slot Interchanger
Timing Characteristics
MM
A[14—0]
CS
AS
DS
R/W
D[7—0]
Figure 18. Asynchronous Read Cycle Timing Using Only CS
MM
A[14—0]
(continued)
t9
t13
READ ADDRESS
t11
t10
t14
READ DATA
5-7065(F)r.3
WRITE ADDRESS
t11
CS
AS
DS
R/W
D[7—0]
t12
t9
WRITE DATA
t10
Figure 19. Asynchronous Write Cycle Timing Using Only CS
Table 46. Asynchronous Microprocessor Interface Timing Using Only CS
SymbolDescriptionMinMaxUnit
t9A[14—0], R/W
t10A[14—0], R/W
t11Pulse Width of CS
t12Pulse Width of CS
t13D[7—0] Output Delay from CS
t14D[7—0] Output Hold from CS
, D[7—0] Input Setup to CS0—ns
, D[7—0] Input Hold from CS0—ns
17. Page 44, Table 28, Test-Pattern Error Injection Register (0x0F), changed register name from test-pattern error
selection register to test-pattern error injection register and added sentence to end of description.
18. Page 46, Table 33, Transmit Highway Configuration Register (Byte 0) (0x1000 + 4i), updated bit 3—bit 2 symbol from XCEOFF to XFBOFF.
19. Page 47, Table 35, Transmit Highway Configuration Register (Byte 2) (0x1002 + 4i), updated bit 2 symbol
name from XEN to XE.
20. Page 48, T able 36, Receive Highway Configuration Register (Byte 0) (0x1800 + 4i), updated bit 3—bit 2 symbol
from RCEOFF to RFBOFF.
For additional information, contact your Microelectronics Group Account Manager or the following:
INTERNET:
E-MAIL:
N. AMERICA: Microelectronics Group, Lucent Technolo
ASIA PACIFIC:Microe le ctron ics Group, Lucent Technologies Singapore Pte. Ltd., 77 Science Park Drive, #03-18 Cintech III, Singapore 118256
CHINA:Microelectro ni cs Gr oup, Luce nt Technologies (China) Co., Ltd., A-F2, 23/F, Zao Fong Universe Building, 1800 Zhong Shan Xi Road, Shanghai
JAPAN:Microelectronics Group, Lucent Technologies Japan Ltd., 7-18, Higashi-Gotanda 2-chome, Shinagawa-ku, Tokyo 141, Japan
EUROPE:Data Requests: MICROELECTRONICS GROUP DATALINE:
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