High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
SMSC LAN9312
257
Revision 1.4 (08-19-08)
DATASHEET
14.2.8.8
Virtual PHY Special Control/Status Register (VPHY_SPECIAL_CONTROL_STATUS)
This read/write register contains a current link speed/duplex indicator and SQE control.
Offset:
Index (decimal):
1DCh
31
Size:
32 bits
BITS
DESCRIPTION
TYPE
DEFAULT
31:16
RESERVED
(See
)
RO
-
15
RESERVED
RO
-
14
Switch Looopback MII
When set, transmissions from the switch fabric Port 0(Host MAC) are not
sent to the Host MAC. Instead, they are looped back into the switch engine.
From the MAC viewpoint, this is effectively a FAR LOOPBACK.
If loopback is enabled during half-duplex operation, then the Enable Receive
Own Transmit bit in the
Port x MAC Receive Configuration Register
must be set for this port. Otherwise, the switch fabric will
ignore receive activity when transmitting in half-duplex mode.
This mode works even if the Isolate bit of the
is set.
R/W
0b
13:8
RESERVED
RO
-
7
Switch Collision Test MII
When set, the collision signal to the switch fabric Port 0(Host MAC) is active
during transmission from the switch engine.
It is recommended that this bit be used only when using loopback mode.
R/W
0b
6:5
RESERVED
RO
-
4:2
Current Speed/Duplex Indication
This field indicates the current speed and duplex of the Virtual PHY link.
RO
1
RESERVED
RO
-
0
SQEOFF
This bit enables/disables the Signal Quality Error (Heartbeat) test.
0: SQE test enabled
1: SQE test disabled
R/W
NASR
[4]
[3]
[2]
Speed
Duplex
0
0
0
RESERVED
0
0
1
10Mbps
half-duplex
0
1
0
100Mbps
half-duplex
0
1
1
RESERVED
1
0
0
RESERVED
1
0
1
10Mbps
full-duplex
1
1
0
100Mbps
full-duplex
1
1
1
RESERVED