vsc880 Vitesse Semiconductor Corp, vsc880 Datasheet - Page 13

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

G52191-0, Rev 4.2
01/05/01
Data Sheet
VSC880
2.0 Packet Mode
2.1 Overview
requesting connection to one or multiple output channels. Acknowledge (ACK) information will be returned to the
transceiver from the switch allowing the port card to start transmitting data. In this mode of operation, no controller
chip is connected to the switch chip as the switch chip handles all arbitration for connection requests. Details on how
the transceiver operates in Packet Mode mode can be found in the VSC870 data sheet and the applications note 31:
“Design Guide for a Packet Based Switch with Distributed Control”. A picture of a self routing system is shown
below. The minimum packet size in this mode of operation is 4 words or 16 bytes.
2.2 Data Encoding Format
Connection Request (CRQ) word format at the serial input and serial output of the switch are described.
2.2.1 Header word Format on the Serial Data Lines
overhead bits are added to designate a header word to the receiving chip. The serial data is transmitted with the MSB
first. If multiple headers are sent in a row, the VSC870 will convert all but the first one into IDLEs.
In Packet Mode (CMODE=LOW), command words can be sent through the transceiver to the switch chip
The data word and command word formats are described in section 1.0. In this section the header word and
The header word format as seen at the serial output of the transceiver or switch chip is shown below. Two
Port Card
Port Card
© VITESSE SEMICONDUCTOR CORPORATION • 741 Calle Plano • Camarillo, CA 93012
Tel: (800) VITESSE • FAX: [phone] • Email: [e-mail]
TXFIFO
RXFIFO
TXFIFO
RXFIFO
VITESSE
SEMICONDUCTOR CORPORATION
Figure 6: Packet Mode System
VSC870
VSC870
Trans
Trans
Internet: www.vitesse.com
Switch Card
Switch
VSC880
Chip
High Performance 16x16
Serial Crosspoint Switch
Page 13