LAN9303 Datasheet, PDF (182/366 Pages) SMSC Corporation – Small Form Factor Three Port 10/100 Managed Ethernet Switch with Single MII/RMII/Turbo MII

13.2.6.8
Small Form Factor Three Port 10/100 Managed Ethernet Switch with Single MII/RMII/Turbo MII
Datasheet
Virtual PHY Special Control/Status Register (VPHY_SPECIAL_CONTROL_STATUS)
Offset:
1DCh
Index (decimal): 31
Size:
32 bits
This read/write register contains a current link speed/duplex indicator and SQE control.
BITS
DESCRIPTION
TYPE
31:16
15
14
13:11
10
9:8
7
6
5
RESERVED
(See Note 13.44)
RESERVED
Switch Looopback Port 0
When set, transmissions from the Switch Fabric Port 0 are not sent to the
External 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
(MAC_RX_CFG_x) must be set for this port. Otherwise, the Switch Fabric
will ignore receive activity when transmitting in half-duplex mode.
Note: This mode works even if the Isolate (VPHY_ISO) bit of the Virtual
PHY Basic Control Register (VPHY_BASIC_CTRL) is set.
RESERVED
Turbo MII Enable
When set, this bit changes the data rate of the MII PHY 100Mbps mode to
200Mbps. The normal Virtual PHY selection mechanism that chooses
between 10 and 100Mbps will instead choose between 10Mbps and
200Mbps.
Note:
When operating at 200Mbps, the drive strength of the MII output
clocks is selected using the RMII/Turbo MII Clock Strength bit.
When at 100 Mbps or 10 Mbps, the drive strength is fixed at 12
mA.
Mode
This field indicates the operating mode of port 0.
00: MII MAC mode
01: MII PHY mode
10: RMII PHY mode
11: RESERVED
Switch Collision Test Port 0
When set, the collision signal to the Switch Fabric Port 0 is active during
transmission from the Switch Engine.
Note: It is recommended that this bit be used only when using loopback
mode.
RMII Clock Direction
0: Selects P0_OUTCLK as an Input
1: Selects P0_OUTCLK as an Output
RMII/Turbo MII Clock Strength
For RMII and 200 Mbps MII PHY modes, a low selects 12 mA drive while a
high selects a 16 mA drive. For 100 Mbps and 10 Mbps MII PHY modes,
the drive strength is fixed at 12mA.
RO
RO
R/W
RO
R/W
RO
R/W
R/W
NASR
Note 13.50
R/W
NASR
Note 13.50
DEFAULT
-
-
0b
-
Note 13.45
Note 13.46
0b
Note 13.47
Note 13.48
Revision 1.3 (08-27-09)
182
DATASHEET
SMSC LAN9303/LAN9303i