Motorola MVME2400 - Manual (Page 70)

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Functional Description
3
Ethernet Interface
The MVME240x module uses Digital Equipment’s DECchip 21143 PCI
Fast Ethernet LAN controller to implement an Ethernet interface that
supports 10Base-T/100Base-TX connections, via an RJ45 connector on
the front panel. The balanced differential transceiver lines are coupled via
on-board transformers.
Every MVME240x is assigned an Ethernet station address. The address is
$08003E2xxxxx, where xxxxx is the unique 5-nibble number assigned to
the board (i.e., every board has a different value for xxxxx).
Each MVME240x displays its Ethernet station address on a label attached
to the base board in the PMC connector keepout area just behind the front
panel. In addition, the six bytes including the Ethernet station address are
stored in the NVRAM (BBRAM) configuration area specified by boot
ROM. That is, the value 08003E2xxxxx is stored in NVRAM. The
MVME240x debugger, PPCBug, has the capability to retrieve the Ethernet
station address via the CNFG command.
Note The unique Ethernet address is set at the factory and should
not be changed. Any attempt to change this address may
create node or bus contention and thereby render the board
inoperable.
If the data in NVRAM is lost, use the number on the label in the PMC
connector keepout area to restore it.
For the pin assignments of the 10Base-T/100Base-TX connector, refer to
Appendix C.
At the physical layer, the Ethernet interface bandwidth is 10Mbit/second
for 10Base T. For the 100Base TX, it is 100Mbit/second. Refer to the
BBRAM/TOD Clock memory map description in the MVME2400-Series
VME Processor Module Programmer’s Reference Guide for detailed
programming information.