![Xilinx Virtex-4 RocketIO Скачать руководство пользователя страница 151](http://html1.mh-extra.com/html/xilinx/virtex-4-rocketio/virtex-4-rocketio_user-manual_3383739151.webp)
Embedded Tri-Mode Ethernet MAC User Guide
151
UG074 (v2.2) February 22, 2010
Auto-Negotiation Interrupt
R
Auto-Negotiation Interrupt
Auto-Negotiation is controlled and monitored through the PCS Management Registers
(see
“Control Register (Register 0)”
) and is consequently only available when
the optional MDIO Management Interface is present.
Overview of Operation
1000BASE-X Standard
illustrates the operation of 1000BASE-X auto-negotiation.
IEEE Std 802.3, Clause 37 describes the 1000BASE-X auto-negotiation function. This
function allows a device to advertise the supported modes of operation to a device at the
remote end of a link segment (the link partner), and to detect corresponding operational
modes advertised by the Link Partner. The operation of the 1000BASE-X auto-negotiation
is summarized:
1.
To enable auto-negotiation, both auto-negotiation (see
“Management Configuration Register”
)
must be enabled. Then, auto-negotiation automatically starts:
♦
After power-up, reset, or enabling of the MDIO interface
♦
Upon loss of synchronization
♦
Whenever the link partner initiates auto-negotiation
♦
Whenever an Auto-Negotiation Restart is requested (see
,
♦
When the PCS/PMA Reset bit is set (see
,
Figure 5-3:
1000BASE-X Auto-Negotiation Overview
Ethernet 1000BA
S
E-X
PC
S
/PMA or
S
GMII
Sub
-L
a
yer
Virtex-4 FPGA
Ethernet
Medi
a
Acce
ss
Controller
PowerPC/
MicroBl
a
ze
Proce
ss
or
s
Ho
s
t Interf
a
ce
EMAC#CLIENTANINTERRUPT
A
u
to-Neg Adv
(Reg 4)
Link P
a
rtner A
b
ility
B
as
e (Reg5)
Link P
a
rtner
A
u
to-Neg Adv
(Reg 4)
Link P
a
rtner A
b
ility
B
as
e (Reg5)
Optic
a
l
Fi
b
re
u
g074_c03_65_080805
www.BDTIC.com/XILINX