VITESSE
SEMICONDUCTOR CORPORATION
Data Sheet
VSC870
Features
• Performs 32-Bit Parallel to Serial and Serial to
Parallel Functions
• Serial Data Rates are 2.0Gb/s
• Designed in Conjunction with the VSC880 Serial
Crosspoint Switch
• Performs Bit Alignment, Word Alignment and
Cell Alignment
• Three Modes of Operation:
Distributed Control
Packet Mode,
Central
Control
Cell Mode
and
Direct Mode
• Support for Multicast and Multiple Input Queues
High Performance Serial
Backplane Transceiver
• Supports Priorities, Camp-on and
Retransmission Capability in Packet Mode
• Built-in Flow Control Channel in Packet Mode
• Supports Cell Synchronization in Cell Mode
• Interfaces Directly with Industry Standard
FIFOs
• Contains Redundant Serial I/Os and Internal
Loopback Mode
• 5V Tolerant TTL Inputs
• Single 3.3V Power Supply
• Available in 192 BGA Package
VSC870 Block Diagram
RFM
RTM/TCLK REN
WSIN
WSOUT
OOS
RESYNEN
RESET
Retiming
Register
TXIN[31:0]
TXTYP[1:0]
TXEN
RTR
ABORT
BYPASS
WCLK
TXOK
RXOK
SCRAM
Transmit
Control
SCRAM
Parallel
to
Serial
TXCLK
Generator
TXSA+/TXSA-
TXSB+/TXSB-
FACLPBK
Alignment
Word Gen
Word/Cell
Aligner
CMU
REFCLK
DLYEN/CCKIN
MODE[1]
MODE[0]
LOOPBACK
RXSA+/RXSA-
RXSB+/RXSB-
RXSEL
TESTEN
VSCTE
RXCLK
Generator
Register
Receive
Control
Retiming
RXWA
RXTYP[1:0]
RXOUT[31:0]
ACK/RCLK
Serial
to
Parallel
CRU
DeSCRAM
RXEN
Signal Detect
CELLSYN
ALIVE
LTIME
G52190-0, Rev 4.1
01/05/01
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Page 1
VITESSE
SEMICONDUCTOR CORPORATION
High Performance Serial
Backplane Transceiver
Data Sheet
VSC870
General Description
The VSC870 serial backplane transceiver has been designed to operate with the VSC880 serial crosspoint switch
to establish a synchronous high performance switching system. The VSC870 can also connect directly to another
transceiver to act as a high bandwidth backplane interconnect link. The transmitter converts a 32-bit parallel interface
operating at 62.5Mb/s to a 34-bit serial data stream operating a 2.125Gb/s. The receiver converts a 34-bit serial
interface operating at 2.125Gb/s to a 32-bit parallel interface operating at 62.5Mb/s. The transceiver performs
automatic bit alignment, word alignment and cell alignment to a connected switch chip or another transceiver. The
parallel interface has been designed with industry-standard FIFOs in mind to provide such features as automatic
packet retransmission, multicast with retransmission, camp-on and support for virtual output queues. These features
can also be bypassed to give the user direct control of the serial data stream. In addition, the transceiver and switch
chip can operate in a early arbitration mode that greatly improves bandwidth utilization. The transceiver also contains
a built-in a flow control channel and redundant serial I/O buffers.
The transceiver and switch chip have been optimized to be used in both distributed-controlled packet-based
switching systems (Packet Mode), and centrally-controlled cell-based switching systems (Cell Mode). The
transceiver can also be directly connected to another transceiver (Direct Mode) for backplane interconnect
applications. The transceiver runs off a 3.3V power supply. The serial I/O buffers contain on-chip termination
resistors (See Figure 19).
Page 2
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
G52190-0, Rev 4.1
01/05/01
VITESSE
SEMICONDUCTOR CORPORATION
Data Sheet
VSC870
Package Pin Descriptions
Symbol
TXIN[31:0]
TXTYP[1:0]
High Performance Serial
Backplane Transceiver
Name
Transmit Parallel Data In
Transmit Word Type
I/O
I
I
Freq
Type
62.5Mb/s
TTL
62.5Mb/s
TTL
62.5Mb/s
TTL
Description
32-bit parallel data input for the transmit side.
If BYPASS is LOW, these signals designate the transmit
word type. If BYPASS is HIGH, these signals directly
control the overhead bits sent on the serial channel.
When TXEN is HIGH, TXIN[31:0], TXTYP[1:0] are
loaded in to the transceiver on the next WCLK. When
TXEN is LOW, the transceiver ignores TXIN[31:0] and
TXTYP[1:0] and sends IDLE words at the serial output.
When RTR is HIGH, the receiving side memory system is
ready to receive data. If LOW, it sends a back pressure
(flow control) signal to the source port card telling it to
stop sending data. In Cell Mode, set RTR LOW to cell
synchronize to the external cell clock. If RTR is HIGH,
cell clock is recovered from the bit stream.
In Packet Mode, when BYPASS is LOW, RTM/TCLK is
set HIGH at the beginning of each data transmission and
set LOW when the data packet has been successfully sent
to all outputs. In Cell Mode, a HIGH pulse represents the
transmit cell clock.
When BYPASS is LOW, RFM is set HIGH whenever a
retransmission of data is required due to contention for
destination ports.
This signal is LOW if MODE[1] is HIGH and the
transceiver is word aligned on the transmit side. After
initialization it will go HIGH for one word clock if there
is a cell clock error.
When REN is HIGH, the transceiver is ready to read data
at TXIN[31:0] and TXTYP[1:0]. This signal can be
forced low by the received flow control signal.
These mode control pins are used to configure link
synchronization. See Section 1.5.
High speed serial differential transmit channel A
High speed serial differential transmit channel B
When LOOPBACK is HIGH, the CRU and signal
detector select the serial data output channel as an input.
High speed serial differential receive channel A
High speed serial differential receive channel B
TXEN
Transmit Enable
I
RTR
Ready To Receive
I
62.5Mb/s
TTL
RTM/TCLK
Retransmit Mode/
Transmit Cell Clock
O
62.5Mb/s
TTL
RFM
Read From Mark
O
62.5Mb/s
TTL
<1MHz
TTL
62.5Mb/s
TTL
<1MHz
TTL
2.125Gb/s
LVDS
2.125Gb/s
LVDS
<1MHz
TTL
2.125Gb/s
LVDS
2.125Gb/s
LVDS
TXOK
Transmit signal OK
O
REN
MODE[1:0]
TXSA+/
TXSA-
TXSB+/
TXSB-
LOOPBACK
RXSA+/
RXSA-
RXSB+/
RXSB-
Read Enable
Mode Control
Transmit Serial Output A
Transmit Serial Output B
Loop Back
Receive Serial Input A
Receive Serial Input B
O
I
O
O
I
I
I
G52190-0, Rev 4.1
01/05/01
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Page 3
VITESSE
SEMICONDUCTOR CORPORATION
High Performance Serial
Backplane Transceiver
Freq
Type
Data Sheet
VSC870
I/O
Description
When RXSEL is LOW and LOOPBACK is LOW, RXSA
is selected as the input to the CRU and RXSB is selected
as the input to the Signal Detector. When RXSEL is
HIGH and LOOPBACK is LOW, RXSB is selected as the
input to the CRU and RXSA is selected as the input to the
Signal Detector.
This output is high if at least one edge transition is
detected every word clock period on the redundant input
serial line.
This signal goes LOW if the VSC870 is word aligned on
the receive side. After initialization, it goes HIGH if there
is error in the IDLE words.
When RXEN is LOW, the RXOUT[31:0] and
RXTYP[1:0] outputs become high impedance.
32-bit parallel data output for the receive side.
If BYPASS is LOW, these signals tell the received word
type. If BYPASS is HIGH, these signals reflect the
overhead bits received on the serial channel.
When RXWA is LOW, RXTYP[1:0] and RXOUT[31:0]
is an IDLE word.
In Packet Mode, the ACK signal will be set high if a
Connection Request on the transmit side is granted. In
Cell mode, a high pulse represents the receive cell clock.
When BYPASS is LOW and ABORT is HIGH, the
connection request and data transmission process is
aborted.
The WSIN signal provides the word clock input and must
be driven by a signal frequency locked to the WSOUT
signal either from itself or another transceiver.
The WSOUT signal is the internally generated word clock
and is synchronized to the transmit word clock.
If RESYNEN is HIGH and the transceiver detects a link
error, it will start the Link Initialization process.
If OOS is HIGH, the transceiver is in the link
initialization process. It is LOW during normal operation.
If SCRAM is HIGH, data words will be scrambled and
descrambled.
BYPASS is set HIGH for direct control and monitoring of
the overhead bits in the serial data streams as in cell mode
and direct mode. This also disables the transceiver Packet
Mode functions.
CELLSYN is set HIGH to allow cell synchronization
during link initialization.
Symbol
Name
RXSEL
Receive Input Select
I
<1MHz
TTL
ALIVE
Redundant Input Alive
O
<1MHz
TTL
<1MHz
TTL
62.5Mb/s
TTL
62.5Mb/s
TTL
62.5Mb/s
TTL
62.5Mb/s
TTL
62.5Mb/s
TTL
62.5Mb/s
TTL
62.5MHz
TTL
62.5MHz
TTL
<1MHz
TTL
<1MHz
TTL
<1MHz
TTL
<1MHz
TTL
<1MHz
TTL
RXOK
RXEN
RXOUT[31:0]
RXTYP[1:0]
RXWA
ACK/RCLK
Receive Signal OK
Receive Enable
Receive Parallel Data
Out
Receive Word Type
Receive Word Available
Acknowledge /
Receive Cell Clock
Connection Request
Abort
Word Synch In
Word Synch Out
Resync Enable
Out Of Sync
Scramble Enable
O
I
O
O
O
O
ABORT
I
WSIN
WSOUT
RESYNEN
OOS
SCRAM
I
O
I
O
I
BYPASS
Bypass Mode
Cell Synchronization
Enable
I
CELLSYN
I
Page 4
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
G52190-0, Rev 4.1
01/05/01
VITESSE
SEMICONDUCTOR CORPORATION
Data Sheet
VSC870
Symbol
DLYEN/
CCKIN
FACLPBK
WCLK
High Performance Serial
Backplane Transceiver
Freq
Type
<1MHz
TTL
<1MHz
TTL
62.5MHz
TTL
62.5MHz
TTL
<1MHz
TTL
<1MHz
TTL
62.5Mb/s
TTL
<1MHz
TTL
3.3V
0V
Name
Delay Enable/Cell Clock
Input
Facility Loopback
Word Clock
I/O
Description
If BYPASS is LOW, this signal can be set HIGH to enable
REN delay mode. In Cell Mode, DLYEN/CCKIN can be
used as an input for cell clock alignment.
When this signal is HIGH, the serial input is looped back
to the serial output. It should be normally set LOW.
The word clock is a delayed version of the WSIN signal.
A 62.5 MHz local reference clock that is used to keep the
CRU close to the incoming bit clock frequency before the
alignment process begins. Is also used as a reference
clock for the CMU.
Global chip reset (active HIGH).
When TESTEN is HIGH, the REFCLK is used in place
of the bit clock for low speed testing. Used for ATE
testing only. Set to logic LOW during normal operation.
LTIME is set HIGH to use the recovered bit clock for the
transmit side.
Used for ATE testing of the parametric NOR chain in the
I/O frame. Set to logic LOW during normal operation.
Clean power supply for CMU
Clean ground for CMU
I
I
O
REFCLK
Local Reference Clock
I
RESET
TESTEN
LTIME
VSCTE
VDDA
VSSA
Reset
Scan Test Enable
Loop Time Mode
NOR Chain Test Enable
CMU Power Supply
CMU Ground
I
I
I
I
P
P
G52190-0, Rev 4.1
01/05/01
©
VITESSE
SEMICONDUCTOR CORPORATION
• 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: (805) 987-5896 • Email: prodinfo@vitesse.com
Internet: www.vitesse.com
Page 5
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