LAN91C95 Просмотр технического описания (PDF) - SMSC -> Microchip

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LAN91C95

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

SMSC -> Microchip 

PACKET FORMAT IN BUFFER MEMORY

The packet format in memory is similar for the

TRANSMIT and RECEIVE areas. The first word

is reserved for the status word, the next word is

used to specify the total number of bytes, and

that in turn is followed by the data area. The

data area holds the packet itself, and its length

is determined by the byte count. The packet

memory format is word oriented.

bit15

bit0

RAM

OFFSET

(DECIMAL)

0

S TAT U S W O R D

2

RESERVED

BYTE COUNT (always even)

4

DATA AREA

1536 Max

CONTROL BYTE

L A S T D ATA BYTE (if odd)

STATUS WORD

BYTE COUNT

DATA AREA

CONTROL BYTE

FIGURE 8 - DATA PACKET FORMAT

TRANSMIT PACKET

Written by CSMA upon transmit

completion (see Status

Register)

Written by CPU

Written by CPU

Written by CPU to control

ODD/EVEN data bytes

RECEIVE PACKET

Written by CSMA upon receive

completion (see RX Frame

Status Word)

Written by CSMA

Written by CSMA

Written by CSMA. Also has

ODD/EVEN bit

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