103 Register Descriptions

(Continued)

RECEIVE CONFIGURATION REGISTER (RCR)

0CH (WRITE)

This register determines operation of the NIC during reception of a packet and is used to program what types of packets to

accept

76543210

MON

PRO

AM

AB

AR

SEP

Bit

Symbol

Description

D0

SEP

SAVE ERRORED PACKETS

0 Packets with receive errors are rejected

1 Packets with receive errors are accepted Receive errors are CRC and Frame

Alignment errors

D1

AR

ACCEPT RUNT PACKETS

This bit allows the receiver to accept packets that

are smaller than 64 bytes The packet must be at least 8 bytes long to be

accepted as a runt

0 Packets with fewer than 64 bytes rejected

1 Packets with fewer than 64 bytes accepted

D2

AB

ACCEPT BROADCAST

Enables the receiver to accept a packet with an all 1’s

destination address

0 Packets with broadcast destination address rejected

1 Packets with broadcast destination address accepted

D3

AM

ACCEPT MULTICAST

Enables the receiver to accept a packet with a multicast

address all multicast addresses must pass the hashing array

0 Packets with multicast destination address not checked

1 Packets with multicast destination address checked

D4

PRO

PROMISCUOUS PHYSICAL

Enables the receiver to accept all packets with a

physical address

0 Physical address of node must match the station address programmed in

PAR0 – PAR5

1 All packets with physical addresses accepted

D5

MON

MONITOR MODE

Enables the receiver to check addresses and CRC on

incoming packets without buffering to memory The Missed Packet Tally counter

will be incremented for each recognized packet

0 Packets buffered to memory

1 Packets checked for address match good CRC and Frame Alignment but not

buffered to memory

D6

reserved

reserved

D7

reserved

reserved

Note

D2 and D3 are ‘‘OR’d’’ together ie if D2 and D3 are set the NIC will accept broadcast and multicast addresses as well as its own physical address To

establish full promiscuous mode bits D2 D3 and D4 should be set In addition the multicast hashing array must be set to all 1’s in order to accept all multicast

addresses

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