VSC8228 Evaluation Board
Software / User Usage Guide
Applications Engineering
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12 of 13
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Rev 1.0
Confidential
01/25/05
8. O
PTIONAL
B
OARD
C
ONFIGURATIONS
a)
SFP Module Configuration:
By default the board is configured to use the SMA connections and not an SFP module.
In order to enable use of an SFP module in the VSC8228 SFP cage, please verify the following:
b)
Reference Clock Configuration Options:
The reference clock can be supplied either to the SMA connectors from an external signal generator or by
using a 3.3V 7x5mm crystal such as the VCC1 series from Vectron.
To use a single-ended crystal oscillator, the board should be configured as described in Table 3.
Component
External Signal
Generator
Single Ended
TTL/CMOS Oscillator
C24, C25
Not installed
C8
Not Installed
0 ohm resistor
C7
Not Installed
Not Installed
C9, C10
0.1uF capacitor
Not Installed
R3, R4
50 ohm resistor
Not Installed
R5
Not Installed
Not Installed
R20, R30
Not Installed
Not Installed
Table 3: Component Installation Options For Reference Clock Source
1) Verify that a jumper is
installed on
J15
in the
TXDIS
position.
2) Remove
C3, C4, C5
and
C6
,
which will disable the
SMA
connection for
TXOUT+/-
and
RXIN+/-.
3) Install
0 Ohm resistors
in
R26, R27, R28 and R29
,
which will route signals
through the SFP interface.