High Performance Two Port 10/100 Managed Ethernet Switch with 32-Bit Non-PCI CPU Interface
Datasheet
BITS
DESCRIPTION
Pass Bad Frames (PASSBAD)
TYPE
DEFAULT
16
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. Refer to Section 9.4, "Address Filtering," on page 114 for
additional information.
15
Hash Only Filtering mode (HO)
R/W
0b
When set, the address check Function operates in the Imperfect address
filtering mode for both physical and multicast addresses. Refer to Section
9.4.2, "Hash Only Filtering," on page 115 for additional information.
14
13
RESERVED
RO
-
Hash/Perfect Filtering Mode (HPFILT)
R/W
0b
When cleared (0), the LAN9312 will implement a perfect address filter on
incoming frames according the address specified in the Host MAC address
registers (Host MAC Address High Register (HMAC_ADDRH) and Host
MAC Address Low Register (HMAC_ADDRL)).
When set (1), the address check function performs imperfect address
filtering of multicast incoming frames according to the hash table specified
in the multicast hash table register. If the Hash Only Filtering mode (HO) bit
15 is set, then the physical (IA) addresses are also imperfect filtered. If the
Hash Only Filtering mode (HO) bit is cleared, then the IA addresses are
perfect address filtered according to the MAC Address register Refer to
Section 9.4.3, "Hash Perfect Filtering," on page 115 for additional
information.
12
11
RESERVED
RO
-
Disable Broadcast Frames (BCAST)
When set, disables the reception of broadcast frames. When cleared,
forwards all broadcast frames to the application.
R/W
0b
10
Disable Retry (DISRTY)
R/W
0b
When set, the Host MAC attempts only one transmission. When a collision
is seen on the bus, the Host MAC ignores the current frame and goes to the
next frame and a retry error is reported in the Transmit status. When reset,
the Host MAC attempts 16 transmissions before signaling a retry error.
9
8
RESERVED
RO
-
Automatic Pad Stripping (PADSTR)
R/W
0b
When set, the Host MAC strips the pad field on all incoming frames, if the
length field is less than 46 bytes. The FCS field is also stripped, since it is
computed at the transmitting station based on the data and pad field
characters, and is invalid for a received frame that has had the pad
characters stripped. Receive frames with a 46-byte or greater length field
are passed to the application unmodified (FCS is not stripped). When
cleared, the Host MAC passes all incoming frames to the host unmodified.
Revision 1.2 (04-08-08)
272
SMSC LAN9312
DATASHEET
SMSC [ SMSC CORPORATION ]
