LAN9500 Datasheet, PDF (159/213 Pages) SMSC Corporation – USB 2.0 to 10/100 Ethernet Controller Promiscuous mode

7.4.1 MAC CONTROL REGISTER (MAC_CR)
Address:
100h
Size:
LAN950x
32 bits
This register establishes the RX and TX operating modes and includes controls for address filtering and packet filtering.
.
Bits
Description
Type
Default
31 Receive All Mode (RXALL)
R/W
0b
When set, all incoming packets will be received and passed on to the
address filtering function for processing of the selected filtering mode on the
received frame. Address filtering then occurs and is reported in Receive
Status. When reset, only frames that pass Destination Address filtering will
be sent to the Application.
30-24 RESERVED
RO
-
23 Disable Receive Own (RCVOWN)
R/W
0b
When set, the MAC disables the reception of frames when TXEN is asserted.
The MAC blocks the transmitted frame on the receive path. When reset, the
MAC receives all packets the PHY gives, including those transmitted by the
MAC.This bit should be reset when the Full Duplex Mode bit is set.
22 RESERVED
RO
-
21 Loopback Operation Mode (LOOPBK)
R/W
0b
Selects the loop back operation modes for the MAC. This is only for full
duplex mode
0 = Normal. No feedback
1 = Internal through MII
In internal loopback mode, the TX frame is received by the Internal MII
interface, and sent back to the MAC without being sent to the PHY.
Note:
When enabling or disabling the loopback mode, it can take up to
10μs for the mode change to occur. The transmitter and receiver
must be stopped and disabled when modifying the LOOPBK bit.
The transmitter or receiver should not be enabled within10μs of
modifying the LOOPBK bit.
20 Full Duplex Mode (FDPX)
R/W
0b
When set, the MAC operates in Full-Duplex mode, in which it can transmit
and receive simultaneously.
19 Pass All Multicast (MCPAS)
R/W
0b
When set, indicates that all incoming frames with a Multicast destination
address (first bit in the destination address field is 1) are received. Incoming
frames with physical address (Individual Address/Unicast) destinations are
filtered and received only if the address matches the MAC Address.
18 Promiscuous Mode (PRMS)
R/W
1b
When set, indicates that any incoming frame is received regardless of its
destination address.
17 Inverse filtering (INVFILT)
R/W
0b
When set, the address check Function operates in Inverse filtering mode.
This is valid only during Perfect filtering mode.
16 Pass Bad Frames (PASSBAD)
R/W
0b
When set, all incoming frames that passed address filtering are received,
including runt frames, collided frames or truncated frames caused by buffer
underrun.
15 Hash Only Filtering mode (HO)
R/W
0b
When set, the address check Function operates in the imperfect address
filtering mode both for physical and multicast addresses.
14 RESERVED
RO
-
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DS00001875A-page 159