Little Board/P5x Technical Manual
2–47
Ethernet Network Interface
This section describes the hardware of the Ethernet interface and discusses relevant software
considerations.

Hardware Description

The Ethernet subsystem is based on the AMD Am79C972 PCnet™ Fast+ Enhanced 10/100 PCI
Ethernet Controller coupled with a Level 1, Inc. LXT970a dual-speed fast Ethernet transceiver. The
Ethernet controller fully supports IEEE 802.3 Ethernet standards, and supports standard 10BaseT
and 100BaseT via a standard RJ-45 connector.
The Ethernet controller interfaces to the PCI portion of the bus. Features of this controller include:
! Speed auto-negotiation (complies with IEEE802.3u standard)
! Full-duplex operation at 10 Mb/s and 100 Mb/s
! Low-power energy modes

Ethernet RJ-45 Interface Connector (J7)

Connector J7 is a standard RJ-45 jack for connecting directly to an Ethernet network using
category 5 UTP/STP cabling.
Table 2– 436 lists the signals and pin numbers of the Ethernet connector, J7:
Table 2– 436. Ethernet RJ-45 Connector (J4)

J7 Pin Function

1TX +
2TX -
3RX +
6RX -
4, 5, 7, 8 Signal Common

Ethernet Interface Software

Manufacturer's Ethernet ID

Each manufacturer of Ethernet network adapters and interfaces is assigned a unique
manufacturer's ID by the IEEE Standards Office. A network address consists of 48 bits. The upper
24 bits are the manufacturer's ID and the lower 24 bits are the board's unique ID.
For developers who are creating network applications, knowing the manufacturer's ID for network
adapters attached to the network may or may not be important.
Ampro's 24-bit manufacturer's ID for Ethernet controllers is displayed in hex as follows:
00 40 53