Motorola MVME162P-244 Series, Installation And Use Manual, Page: 108 / 146

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Functional Description
4
Notes
MVME162P4 boards do not monitor power 5 Vdc
power and assert IP reset if the power falls too low. Instead,
IP reset is handled by the162Bug firmware’s ENV
command, as described in Chapter 3. The IP reset is also
driven active by the power-up reset signal.
Two IP modules plugged into the same MVME162P4 board can
not use the Strobe
∗
signal unless the jumper is removed from J19.
This will disconnect the Strobe
∗
output from the Petra/IP2 ASIC.
Ethernet Interface
The MVME162P4 uses the Intel 82596CA LAN coprocessor to implement
the optional Ethernet transceiver interface. The 82596CA accesses local
RAM using DMA operations to perform its normal functions. Because the
82596CA has small internal buffers and the VMEbus has an undefined
latency period, buffer overrun may occur if the DMA is programmed to
access the VMEbus. Therefore, the 82596CA should not be programmed
to access the VMEbus.
Every MVME162P4 that is built with an Ethernet interface is assigned an
Ethernet Station Address. The address is $0001AF0xxxxx where xxxxx is
the unique 5-nibble number assigned to the board (i.e., every
MVME162P4 has a different value for xxxxx).
Each board has an Ethernet Station Address displayed on a label attached
to the VMEbus P2 connector. In addition, the six bytes including the
Ethernet address are stored in the BBRAM configuration area. That is,
0001AF0xxxxx is stored in the BBRAM. The upper four bytes (0001AF0x)
are read at $FFFC1F2C; the lower two bytes (xxxx) are read at
$FFFC1F30. The MVME162 debugger has the capability to retrieve or set
the Ethernet address.
If the data in BBRAM is lost, use the number on the label on backplane
connector P2 to restore it.
The Ethernet transceiver interface is located on the MVME162P4 main
board, and the industry-standard DB15 connector is located on the
MVME712x transition board.