Figure 34. line side interface loopback path, 12 clocks, 1 system interface reference clocks – Intel IXF1104 User Manual
Page 127: Clocks 5.12.1 system interface reference clocks, Line side interface loopback path, Figure 34
Intel
®
IXF1104 4-Port Gigabit Ethernet Media Access Controller
127
Datasheet
Document Number: 278757
Revision Number: 009
Revision Date: 27-Oct-2005
When the IXF1104 MAC is configured in this loopback mode, all of the MAC functions and
features are available, including flow control and pause-packet generation.
To configure the IXF1104 MAC to use the line-side loopback mode, the
FIFO (Line-Side Loopback) Ports 0 - 3 ($0x61F)"
must be configured. Each IXF1104 MAC port
has a unique bit in this register designated to control the loopback. It is possible to have individual
ports in a loopback mode while other ports continue to operate in a normal mode.
Note:
Line side interface loopback packets also appear at the SPI3 interface.
5.12
Clocks
The IXF1104 MAC system interface has several reference clocks, including the following:
•
SPI3 data path input clocks
•
RGMII input and output clocks
•
MDIO output clock
•
JTAG input clock
•
I
2
C clock
•
LED output clock.
This section details the unique clock source requirements.
5.12.1
System Interface Reference Clocks
The following system interface clock is required by the IXF1104 MAC:
•
CLK125
Figure 34. Line Side Interface Loopback Path
RX FIFO
SPI3 Interface
Block
TX
RX
Line Side
Interface
MAC
TX FIFO
B3230-01
Line Side Internal Loopback