91C94 Datasheet, PDF (37/120 Pages) SMSC Corporation – ISA/PCMCIA SINGLE CHIP ETHERNET CONTROLLER WITH RAM

In order to force another collision, TXENA must
be set to 1 again.
LOOP - Local Loopback. When set, transmit
frames are internally looped to the receiver after
the encoder/decoder. Collision and Carrier
Sense are ignored. No data is sent out. Defaults
low to normal mode.
TXENA - Transmit enabled when set. Transmit
is disabled if clear. When the bit is cleared the
LAN91C94 will complete the current
transmission before stopping. When stopping
due to an error, this bit is automatically cleared.
LOOPBACK MODES
AUI EPH LOOP LOOP FDUPLX
X
1
X
0
1
0
0
0
X
0
X
X
1
1
0
1
0
1
0
0
LOOPS AT
EPH Block
ENDEC
Cable
10BASE-T Driver
Normal CSMA/CD - No
Loopback
TRANSMITS TO
NETWORK
N
N
Y
Y
Y
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