LAN91C95 Ver la hoja de datos (PDF) - SMSC -> Microchip

Número de pieza

componentes Descripción

Lista de partido

LAN91C95

ISA/PCMCIA Full Duplex Single-Chip Ethernet and Modem Controller with RAM

SMSC -> Microchip 

RECEIVE FRAME STATUS WORD

This word is written at the beginning of each receive frame in memory. It is not available as a register.

HIGH

BYTE

ALGN

ERR

BROD

CAST

BAD

CRC

ODD

TOO

FRM TOOLNG SHORT

LOW

BYTE

MULT

HASH VALUE

CAST

5

4

3

2

1

0

ALGNERR - Frame had alignment error.

BRODCAST - Receive frame was broadcast.

BADCRC - Frame had CRC error.

ODDFRM - This bit when set indicates that the

received frame had an odd number of bytes.

TOOLNG - The received frame is longer than

802.3 maximum size (1518 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:

TOOSHORT - The received frame is shorter than

802.3 minimum size (64 bytes on the cable).

ADDRESS

ED 00 00 00 00 00

0D 00 00 00 00 00

01 00 00 00 00 00

2F 00 00 00 00 00

HASH VALUE 5-0

000 000

010 000

100 111

111 111

MULTICAST TABLE BIT

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.

31

Share Link: