LXT974/LXT975 — Fast Ethernet 10/100 Quad Transceivers
2.5.4.2
2.5.4.3
Data Errors
Figure 16 shows normal reception. When the LXT974/975 receives invalid symbols from the line,
it asserts RX_ER, as shown in Figure 17.
Collision Indication
Figure 18 shows normal transmission. The LXT974/975 detects a collision if transmit and receive
are active at the same time. As shown in Figure 19, upon detection of a collision, the COL output
is asserted and remains asserted for the duration of the collision.
Figure 16. 100BASE-TX Reception with No Errors
RX_CLK
RX_DV
preamble SFD SFD DA DA
DA
DA
CRC
CRC
CRC
CRC
RXD<3:0>
RX_ER
Figure 17. 100BASE-TX Reception with Invalid Symbol
RX_CLK
RX_DV
DA
XX
XX
XX
XX
XX
XX
XX
XX
XX
preamble SFD SFD DA DA
RXD<3:0>
RX_ER
Figure 18. 100BASE-TX Transmission with No Errors
TX_CLK
TX_EN
P
R
E
A
M
B
L
E
DA
DA DA DA
DA DA DA DA DA
TXD<3:0>
CRS
COL
Figure 19. 100BASE-TX Transmission with Collision
TX_CLK
TX_EN
P
R
E
A
M
B
L
E
JAM
JAM
JAM
JAM
TXD<3:0>
CRS
COL
34
Datasheet
INTEL [ INTEL ]
