LAN91C96 datasheet(39/125 Pages) SMSC

39 / 125 page

Non-PCI Single-Chip Full Duplex Ethernet Controller with Magic Packet

SMSC LAN91C965v&3v

Page 39

Rev. 03-28-07

DATASHEET

ODDFRM - This bit when set indicates that the received frame had an odd number of bytes.

TOOLNG - The received frame is longer than the 802.3 maximum size (1518 bytes on the cable).

TOOSHORT - The received frame is shorter than the 802.3 minimum size (64 bytes on the cable).

HASH VALUE - Provides the hash value used to index the Multicast Registers. Can be used by receive

routines to speed up the group address search. The hash value consists of the six most significant bits of

the CRC calculated on the Destination Address, and maps into the 64 bit multicast table. Bits 5,4,3 of the

hash value select a byte of the multicast table, while bits 2,1,0 determine the bit within the byte selected.

Examples of the address mapping are shown in the table below:

ADDRESS

HASH VALUE 5-0

MULTICAST TABLE BIT

ED 00 00 00 00 00

0D 00 00 00 00 00

01 00 00 00 00 00

2F 00 00 00 00 00

000 000

010 000

100 111

111 111

MT-0 bit 0

MT-2 bit 0

MT-4 bit 7

MT-7 bit 7

MULTCAST - Receive frame was multicast. If hash value corresponds to a multicast table bit that is set,

and the address was a multicast, the packet will pass address filtering regardless of other filtering criteria.

LAN91C96 Datasheet(PDF) 39 Page - SMSC Corporation