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Functional Description
Ethernet Interface
MCPN750A provides an Ethernet interface via the 21143 device. This device, along with an external Level One LXT970ATC device, implement a 10BaseT/100BaseTX autoselect ethernet interface. The Ethernet interface is routed to an RJ45 connector located at the front panel of the board. The MCPN750A SBC also supports optional routing of the ethernet signals to the J5 connector for ethernet connection on the transition module. The front panel or transition module option is selected by installing the corresponding components during board assembly.
Every board will be assigned an Ethernet Station Address. The address is $000A1Exxxxx where xxxxx is the unique number assigned to the board. Each board’s Ethernet Station Address is displayed on a label attached to the PMC
These bytes are stored in bytes 0x14 through 0x19 in the Ethernet SROM. The Ethernet information in the SROM is stored in DEC Version 3 format. For further information on this refer to the Digital Semiconductor 21x4x Serial ROM Format, Version 3.03 document.
Use extreme caution when viewing the contents of the Ethernet SROM via the PPCBug SROM command. If the contents are modified incorrectly, this could cause the PPCBug Firmware Ethernet Drivers to work incorrectly.
Note: When the board is shipped from the factory, it should contain the proper SROM data for the MCPN750A, which has 10BaseT/100BaseTX Ethernet connections. There should not be a need to change the SROM contents.
For the pin assignments of the 10BaseT/100BaseTX connector, refer to the Table on page
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