Register Descriptions

 

 

 

 

 

 

 

Field

 

Bit(s)

Initial

Description

 

 

Value

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Multicast Promiscuous Enabled

 

 

 

 

 

0b = Disabled.

 

MPE

 

4

0b

1b = Enabled.

 

 

When set, passes without filtering out all received multicast packets.

 

 

 

 

 

 

 

 

 

 

Otherwise, the Ethernet controller accepts or rejects a multicast

 

 

 

 

 

packet based on its 4096-bit vector multicast filtering table.

 

 

 

 

 

 

 

 

 

 

 

Long Packet Reception Enable

 

 

 

 

 

0b = Disabled.

 

 

 

 

 

1b = Enabled.

 

LPE

 

5

0b

LPE controls whether long packet reception is permitted. When LPE

 

 

is cleared, the Ethernet controller discards packets longer than

 

 

 

 

 

1522 bytes. When LPE is set, the Ethernet controller discards

 

 

 

 

 

packets that are longer than 16384 bytes.

 

 

 

 

 

For the 82541xx and 82547GI/EI, packets larger than 2 KB require

 

 

 

 

 

full duplex operation.

 

 

 

 

 

 

 

 

 

 

 

Loopback mode.

 

 

 

 

 

Controls the loopback mode of the Ethernet controller.

 

 

 

 

 

00b = No loopback.

 

 

 

 

 

01b = Undefined.

 

 

 

 

 

10b = Undefined.

 

LBM

 

7:6

0b

11b = PHY or external SerDes loopback.

 

 

All loopback modes are only allowed when the Ethernet controller is

 

 

 

 

 

 

 

 

 

 

configured for full-duplex operation. Receive data from transmit

 

 

 

 

 

data looped back internally to the SerDes or internal PHY. In TBI

 

 

 

 

 

mode (82544GC/EI), the EWRAP signal is asserted.

 

 

 

 

 

Note: The 82540EP/EM, 82541xx, and 82547GI/EI do not support

 

 

 

 

 

SerDes functionality.

 

 

 

 

 

 

 

 

 

 

 

Receive Descriptor Minimum Threshold Size

 

 

 

 

 

The corresponding interrupt ICR.RXDMT0 is set each time the

 

 

 

 

 

fractional number of free descriptors becomes equal to RDMTS.

 

 

 

 

 

The following table lists which fractional values correspond to

 

 

 

 

 

RDMTS values. The size of the total receiver circular descriptor

 

RDMTS

 

9:8

0b

buffer is set by RDLEN. See Section 13.4.27 for details regarding

 

 

 

 

 

RDLEN.

 

 

 

 

 

00b = Free Buffer threshold is set to 1/2 of RDLEN.

 

 

 

 

 

01b = Free Buffer threshold is set to 1/4 of RDLEN.

 

 

 

 

 

10b = Free Buffer threshold is set to 1/8 of RDLEN.

 

 

 

 

 

11b = Reserved.

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

Reserved

 

11:10

0b

Should be written with 0b to ensure future compatibility.

 

 

 

 

 

Reads as 0b.

 

 

 

 

 

 

 

 

 

 

 

Multicast Offset

 

 

 

 

 

The Ethernet controller is capable of filtering multicast packets

 

 

 

 

 

based on 4096-bit vector multicast filtering table. The MO

 

 

 

 

 

determines which bits of the incoming multicast address are used in

 

MO

 

13:12

0b

looking up the 4096-bit vector.

 

 

 

 

 

00b = bits [47:36] of received destination multicast address.

 

 

 

 

 

01b = bits [46:35] of received destination multicast address.

 

 

 

 

 

10b = bits [45:34] of received destination multicast address.

 

 

 

 

 

11b = bits [43:32] of received destination multicast address.

 

 

 

 

 

 

 

 

 

 

 

Reserved

 

Reserved

 

14

0b

Should be written with 0 to ensure future compatibility

 

 

 

 

 

Reads as 0

 

 

 

 

 

 

Software Developer’s Manual

 

 

297

Page 311
Image 311
Intel Intel Gigabit Ethernet Controllers, PCI-X manual Mpe, Lpe, Lbm, Rdmts