![Intel IXP45X Скачать руководство пользователя страница 229](http://html1.mh-extra.com/html/intel/ixp45x/ixp45x_developers-manual_2073092229.webp)
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
229
Ethernet MACs—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
6.0
Ethernet MACs
The functionality supported by the MII Interfaces is tightly coupled with the code
written on the Network Processor Engine (NPE) core. This chapter details the full
hardware capabilities of the MII Interface contained within the Ethernet coprocessor of
the Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors. The features
accessible by the user are described in the Intel
®
IXP400 Software Programmer’s
Guide and may be a subset of the features described below.
Note:
Not all of the IXP45X/IXP46X network processors have this functionality. For details,
see
Table 97, “Processors: Network Processor Functions” on page 222
The IXP45X/IXP46X network processors contain three NPEs. All of the NPEs may be
used to process Ethernet traffic utilizing the xMII (MII/SMII) interfaces. Each NPE core
used for Ethernet traffic connects to a Transmit FIFO and Receive FIFO through the NPE
Coprocessor interface. These Transmit and Receive FIFOs are used to buffer data
between the Ethernet Media Access Controller (MAC) and the NPE core.
The Transmit FIFO, Receive FIFO, and MAC are contained in an NPE coprocessor unit
called the Ethernet Coprocessor. The MAC contained in the Ethernet coprocessor is
compliant to the IEEE 802.3 specification as well as handling flow control for the
IEEE 802.3Q VLAN specification.
One Management Data Interface is shared between all of the xMII interfaces. The
single Management Data Interface is used to configure the physical devices attached to
each of the xMII interfaces. The Management Data Interface is accessible by
manipulating the Management Data Registers associated with Ethernet MAC
Coprocessor B0, see
“Register Descriptions Ethernet MACs” on page 239
shows a typical application that may be used in connecting to the xMII interface. In
addition to supporting an MII connection, the interface may be configured to support
SMII interfaces.
Figure 28.
Multiple Ethernet PHYS Connected to Processor
B4228-002
Intel
®
IXP46X
Network
Processor
Quad
Ethernet
Bridge
Ethernet
PHY
Management
Data Interface
MII A
MII B
Switched
LAN
WAN