SMC Networks SMC91C95 User Manual

Page 44

I/O SPACE - BANK0

OFFSET

NAME

TYPE

SYMBOL

RECEIVE CONTROL

REGISTER

READ/WRITE

RCR

HIGH

BYTE

SOFT_

RST

FILT_

CAR

STRIP_

CRC

RXEN

LOW

BYTE

ALMUL

PRMS

RX_

ABORT

SOFT_RST - Software activated Reset. Active
high. Initiated by writing this bit high and
terminated by writing the bit low. The SMC91C95
configuration is not preserved, except for
Configuration, Base, and IA0-IA5 Registers. The
EEPROM in both ISA and PCMCIA mode is not
reloaded after software reset.

FILT_CAR - Filter Carrier. When set filters leading
edge of carrier sense for 12 bit times. Otherwise
recognizes a receive frame as soon as carrier
sense is active.

STRIP_CRC - When set it strips the CRC on
received frames. When clear the CRC is stored in
memory following the packet. Defaults low.

RXEN - Enables the receiver when set. If cleared,
completes receiving current frame and then goes
idle. Defaults low on reset.

ALMUL - When set accepts all multicast frames
(frames in which the first bit of DA is '1'). When
clear accepts only the multicast frames that match
the multicast table setting. Defaults low.

PRMS - Promiscuous mode. When set receives all
frames. Does not receive its own transmission
unless it is in full duplex.

RX_ABORT - This bit is set if a receive frame is
aborted due to length longer than 1532 bytes. The
frame will not be received. The bit is cleared by
RESET or by the CPU writing it low.

RX_ABORT

RX_OVRN_INT

Packet Too Long

Run out of Memory
During Receive