vsc880 Vitesse Semiconductor Corp, vsc880 Datasheet - Page 4

• Manufacturer Part Number: vsc880
• Description: High Performance 16x16 Serial Crosspoint Switch Semiconductor Corporation
• Manufacturer: Vitesse Semiconductor Corp

High Performance 16x16
Serial Crosspoint Switch
Page 4
Functional Description
operation: Packet Mode and Cell Mode. In Packet mode, the chip set provides a switching system to support variable
length, self-routing data packets. In Cell Mode, the chip set provides a cell synchronous switching system with a user
defined scheduler. In this mode, it can support only fixed length data packets (cells). Routing decisions are carried
out in the scheduler and crosspoint configuration is synchronized to a cell clock. The scheduler configures the switch
matrix using the parallel interface. To conserve power, each serial port quadrant can be powered down if not used.
discussion includes some of the transceiver operation (see the VSC870 data sheet). The two major operation modes
are described separately in the Packet Mode and the Cell Mode sections.
1.0 Common Features
1.1 Synchronization
1.1.1 Link Characteristic
initialized simultaneously at power up, or separately when a link error occurs. A link is first bit synchronized, then
word synchronized and, if CMODE is HIGH, cell synchronized. In Packet or Cell mode, the switch acts as the
master, generating the bit clock along with the word and cell boundary information. The transceivers act as slaves,
recovering the bit clock, word clock and cell clock. The transceiver also contains redundant serial inputs and outputs
which can be used with a redundant switch chip.
VDD1, VDD2,
VDD3, VDD4
LOCKDET
VSCOPNC
VSCIPNC
VSCTE
VDDA
The VSC880 switch can be used in conjunction with the VSC870 transceivers to support two modes of
The following section gives a detailed functional description of the operation of the switch chip. Most of the
The serial link is used to connect the switch chip to transceivers. These links operate at 2.125 Gb/s and are
VSSA
VMM
Pin
NOR Chain Test Enable
CMU Power Supply
Core Power Supply
NOR Chain Output
CMU Lock Detect
NOR Chain Input
Serial Port Power
CMU Ground
Supplies
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
Name
Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]
VITESSE
SEMICONDUCTOR CORPORATION
I/O
O
O
P
P
P
P
I
I
2 ~ 2.5V
Internet: www.vitesse.com
<1MHz
<1MHz
<1MHz
<1MHz
VECL
Freq
Type
3.3V
3.3V
TTL
TTL
TTL
0V
This signal is LOW while the CMU is acquiring lock.
Used for ATE testing of the parametric NOR chain in the I/O
frame. Set to logic LOW during normal operation.
Used for ATE testing of the parametric NOR chain in the I/O
frame. Set to logic LOW during normal operation.
Used for ATE testing of the parametric NOR chain in the I/O
frame. Leave output open during normal operation.
VDD1 = Serial Port 0-3 power supply
VDD2 = Serial Port 4-7 power supply
VDD3 = Serial Port 8-11 power supply
VDD4 = Serial Port 12-15 power supply
Clean power supply for CMU
Clean ground for CMU
Core power supply
Description
Data Sheet
VSC880
G52191-0, Rev 4.2
01/05/01