
Chapter 3
Functional Operation
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Rev. 3.00
April 2003
AMD-8111 HyperTransport I/O Hub Data Sheet
AMD Preliminary Information
3.10
LAN Ethernet Controller
3.10.1
Interface
s
3.10.1.1
Software Interface
The software interface to the network controller is divided into three parts. One part is the PCI
configuration registers used to identify the network controller and to setup the configuration of the
device. The setup information includes the memory mapped I/O base address and the routing of the
network controller interrupt channel. This allows for a jumperless implementation.
The second portion of the software interface is the direct access to the I/O resources of the network
controller. The host CPU accesses these registers for performance tuning, selecting options, statistics
collecting, and starting transmissions.
The third portion of the software interface is the descriptor and buffer areas that are shared between
the software and the network controller during normal network operations. The descriptor area
boundaries are set by the software and do not change during normal network operations. There is a
separate descriptor area for each receive and transmit priority queue. The descriptor space contains
relocatable pointers to the network frame data, and it is used to transfer frame status from the network
controller to the software. The buffer areas are locations that hold frame data for transmission or that
accept frame data that has been received.
3.10.1.2
Network Interface
The network controller can be connected to an IEEE 802.3 or proprietary network through the IEEE
802.3-compliant Media Independent Interface (MII). The MII is a nibble-wide interface to an external
100-Mbit/s and/or 10-Mbit/s transceiver device.
The network controller supports both half-duplex and full-duplex operation on the network interface.
3.10.2
Device Operation
3.10.2.1
Initialization
Before the network controller is ready for operation, several registers must be initialized. First certain
read-only fields in PCI configuration space must be initialized by writing to alias registers in PCI
configuration space. These fields contain values such as Subsystem Vendor ID and Maximum
Latency, which depend on the board in which the device is installed and should not be changed by
operating system software. Once these hardware parameters have been set up, the normal BIOS
initialization software can write to the writable fields in PCI configuration space. In particular, the
Memory-Mapped I/O Base Address Register in configuration space must be initialized before any of
the memory-mapped registers can be accessed.