
324
Registers
Chapter 4
AMD-8111 HyperTransport I/O Hub Data Sheet
24674
Rev. 3.00
April 2003
AMD Preliminary Information
LAN Ethernet Controller Command 2 (CMD2)
ENC050
Default:
Bits
31
0000_0000h
Description
VALBIT3
.
Value bit for byte 3
. Read-write. The value of this bit is written to any bits in the CMD2
register that correspond to bits in the CMD2[30:24] bit map
fi
eld that are set to 1.
Reserved.
CONDUIT_MODE. Disables backoff and retry
. Transmit retry and frame discard is controlled by
COL and CRS. See Conduit Mode section for details.
28:24 Reserved.
23
VALBIT2
.
Value bit for byte 2
. Read-write. The value of this bit is written to any bits in the CMD2
register that correspond to bits in the CMD2[22:16] bit map
fi
eld that are set to 1.
22:20 Reserved.
19
RPA. Runt Packet Accept
. This bit forces the controller to accept runt packets (packets shorter than
64 bytes). The minimum packet size that can be received is 12 bytes including the FCS.
18
DRCVPA. Disable Receive Physical Address
. When set, the physical address detection (Station or
node ID) of the controller is disabled. Frames addressed to the node
’
s individual physical address will
not be recognized.
17
DRCVBC. Disable Receive Broadcast
. When set, disables the controller from receiving broadcast
messages. Used for protocols that do not support broadcast addressing, except as a function of
multicast. DRCVBC is cleared by activation of H_RESET (broadcast messages will be received) and
is unaffected by the clearing of the RUN bit.
16
PROM. Promiscuous Mode
. When PROM = 1, all incoming receive frames are accepted, regardless
of their destination addresses.
15
VALBIT1
.
Value bit for byte 1
. Read-write. The value of this bit is written to any bits in the CMD2
register that correspond to bits in the CMD2[14:8] bit map
fi
eld that are set to 1.
14
Reserved.
13
ASTRIP_RCV. Auto Strip Receive
. When set, ASTRIP_RCV enables the automatic pad stripping
feature. For any receive frame whose length
fi
eld has a value less than 46, the pad and FCS
fi
elds are
stripped and not placed in the FIFO.
12
RCV_DROP0.
If this bit is set, receive frames assigned to ring 0 are dropped if no descriptor is
available when the frame is ready to be written to system memory. If the bit is 0, these frames are
saved until descriptors are available.
11
EMBA. Enable Modi
fi
ed Back-off Algorithm
(see Contention Resolution section in Media Access
Management section for more details). If EMBA is set, a modi
fi
ed back-off algorithm is implemented.
10
DXMT2PD. Disable Transmit Two Part Deferral
(see Medium Allocation section in the Media Access
Management section for more details). If DXMT2PD is set, Transmit Two Part Deferral is disabled.
9
LTINTEN. Last Transmit Interrupt Enable
. When this bit is set to 1, the LTINT bit in transmit
descriptors can be used to determine when transmit interrupts occur. The Transmit Interrupt (TINT) bit
is set after a frame has been copied to the Transmit FIFO if the LTINT bit in the frame
’
s last transmit
descriptor is set. If the LTINT bit in the frame
’
s last descriptor is 0, TINT is not set after the frame has
been copied to the Transmit FIFO.
Attribute:
Read-write; write mode N.
30
29