RTL8169
2002/03/27
Rev.1.21
54
Tx Status Descriptor (after transmitting, OWN=0, Tx status mode)
After having transmitted, the Tx descriptor turns into a Tx status descriptor.
bit
31 30 29 28 27 26
16 15
8 7 6 5 4 3 2 1 0
O
W
N
=
0
E
O
R
F
S
L
S
R
S
V
D
R
S
V
D
R
S
V
D
R
S
V
D
R
S
V
D
R
S
V
D
R
S
V
D
R
S
V
D
RSVD
RSVD
Offset 0
VLAN_TAG
RSVD
T
A
G
C
R
S
V
D
VIDL PRIO
C
FI
VIDH
Offset 4
TX_BUFFER_ADDRESS_LOW
Offset 8
TX_BUFFER_ADDRESS_HIGH
Offset 12
Offset#
Bit#
Symbol
Description
0 31
OWN
Ownership:
This bit, when set, indicates that the descriptor is owned
by the NIC. When cleared, it indicates that the descriptor is owned by
the host system. NIC clears this bit when the relative buffer data is
already transmitted. In this case, OWN=0.
0 30
EOR
End of Descriptor Ring:
When set, indicates that this is the last
descriptor in descriptor ring. When NIC’s internal transmit pointer
reaches here, the pointer will return to the first descriptor of the
descriptor ring after transmitting the data relative to this descriptor.
0 29
FS
First Segment Descriptor:
This bit, when set, indicates that this is the
first descriptor of a Tx packet, and that this descriptor is pointing to the
first segment of the packet.
0 28
LS
Last Segment Descriptor:
This bit, when set, indicates that this is the
last descriptor of a Tx packet, and that this descriptor is pointing to the
last segment of the packet.
0 27:0
RSVD
Reserved
4 31:18
RSVD
Reserved
4 17
TAGC
VLAN Tag Control Bit:
1: Enable; 0: Disable.
1: Add TAG. 0x8100 (Ethernet encoded tag protocol ID, indicating
that this is an IEEE 802.1Q VLAN packet) is inserted after source
address, and 2 bytes are inserted after tag protocol ID from
VLAN_TAG field in transmit descriptor.
0: Packet remains unchanged when transmitting. I.e., the packet
transmitted is the same as it was passed down by the upper layer.
4 16
RSVD
Reserved
cont...
