Micro Linear ML6651, Руководство пользователя

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ML6651
6 November 2001 User’s Guide
TESTING
Install the twisted pair and fiber cables. Use the attenuators
in the fiber links if desired. The board’s RJ45 jack has a
straight or NIC wiring so be sure to use a crossover copper
cable or a separate crossover adapter.
The normal mode of operation is Transparent Mode, or plug-
and-play mode, if a common denominator is found between
the two copper end ports.
The plug and play mode is as follows:
Connect the power source and turn it on. LEDs should start
to blink and finally are settled to either the 10Mbs or
100Mbs LEDs, whichever is the common speed (must be a
pair). It may take a few cycles with LEDs running up and
down if Auto-negotiation is taking place. If the AN_DT LEDs
keeps blinking or only one of the speed LED is ON instead
of a pair (both 10 or both 100), then no link has been
established. Recheck the configurations of your copper
stations and reconfigure the eval-board if needed (to Non-
Transparent or Fixed mode).
If one of the TP link partner’s capabilities is changed, auto-
negotiation may be restarted automatically by disconnecting
and reconnecting the cables. Alternatively, auto-negotiation
may be restarted from the Netcom’s SmartBits 2000 software
graphical interface. If no common operating mode is found
between two link partners the red (D8, D9 LED(s) will
remain flashing for the auto-negotiation capable link
partner(s) as long as FLP and FLNP bursts are received.
One way to test the ML6651 Evaluation Board is shown in
Figure 4. The Netcom SmartBit 2000 system can have its
port configured to look like a legacy or auto-negotiable
station. The configuration of the ML6651 eval board can be
changed accordingly. Once link is established, data (with
variable lengths and patterns) can be transferred from one
Netcom port and received at another.
To measure the launch power at the transmitter, disconnect
the fiber optic cable from the optical receiver module and
connect it to the power meter. Measure the power while the
pattern generator is transmitting. Note that the reading of the
power meter applies to the average launch power: Average
launch power (dBm) = peak launch power (dBm) minus
3dBm
To measure optical rise and fall time connect the fiber optic
cable from the optical transmitter to the optical waveform
receiver and then to the scope. You need to program the
data to a specific pattern like AAhex (not random).
To measure optical sensitivity use the variable attenuator to
attenuate the power. Start to transmit a random pattern and
then observe that the Link LED stays on. Then attenuate the
optical signal during transmission until the Link LED goes
off. Now slightly increase the optical signal through the
attenuator to turn the Link LED back on. Finally measure
the receive power by the power meter to find the receive
sensitivity.
Evaluation Board Errata
This applys to all four board configurations to avoid
confusion. Do not stuff C49 & C50 located upper right
corner of schematics on full size boards and top center on
the mini board. For a complete discussion of the use of the
control & configuration pins, see the ML6651 datasheet
section Configuration and Control Options and Guidelines.
GENERAL DESCRIPTION
Figure 2. Test Circuit Block Diagram
NIC or
HUB or
Switch or
Netcom SmartBits 2000
RJ45
ML6651Evaluation Board
RJ45
Fiber
Optic
xcvr
Other Media Converter
or Netcom SmartBits
2000 port with fiber
optical xcvr
Other TP link
or Netcom
SmartBits
2000 TP
port if needed
FLPs FNLPs FLPs