VSC8228 Evaluation Board
Software / User Usage Guide
Applications Engineering
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3 of 13
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Rev 1.0
Confidential
01/25/05
1. I
NTRODUCTION
The VSC8228 is a dual repeater/retimer for Fibre Channel, Gigabit Ethernet, SONET/SDH, and Infiniband
applications. The VSC8228 contains dual FibreTimer
TM
clock recovery units (CRU) for bidirectional signal
conditioning in system interconnect and serial backplane applications. The device supports rates from 125Mb/s up to
4.25Gb/s. Using a single reference clock for acquisition, the VSC8228 retransmits the incoming serial data
synchronously to the reference clock in retimer mode or to the incoming data in repeater mode. In the retimer mode,
add/drop elasticity buffers insert/delete Fibre Channel fill words to account for timing differences in the incoming
data and local reference clock.
An analog signal detect function is integrated into both channels. In the retimer mode, the device monitors the
incoming data for run-length violations and K28.5- symbols. The inputs on both the transmit and receive channels
can be looped back to the outputs of the opposite channels for diagnostic purposes. The device provides a built-in
pattern generator and checker. An optional half-rate clock for SGMII applications is provided on the receive channel
output.
A high degree of signal integrity is maintained via differential I/O, on-chip input and output terminations, input
equalization, and output de-emphasis. The programmable input equalization circuit compensates for the frequency
limitations of long printed circuit board (PCB) traces, backplanes, connectors, and cables. Equalization, de-
emphasis, output drive levels, data rate, and other features are configured through industry standard serial interfaces
(Two-wire or SPI).
This board was designed for extensive characterization of the VSC8228. It has the following features:
•
Single 3.3V supply (1.2V is regulated on-board)
•
Standard SFP Cage
Figure 1: VSC8228 Board Layout