DJLXT907ALC.A4 Cortina Systems Inc, DJLXT907ALC.A4 Datasheet - Page 15

• Manufacturer Part Number: DJLXT907ALC.A4
• Manufacturer: Cortina Systems Inc

Specifications of DJLXT907ALC.A4

• Lead Free Status / RoHS Status: Not Compliant

2.3.1
2.3.2
Datasheet
Document #: 249097
Revision #: 002
Rev. Date: June 19, 2001
Note: For full-duplex operation on twisted-pair and AUI ports, the collision detection circuitry must be
Polarity Reverse Function
The LXT901/907 polarity reverse function uses both link pulses and End-of-Frame data to
determine the polarity of the received signal. If Link Integrity Testing is disabled, polarity detection
is based only on received data. A reversed polarity condition is detected when eight opposite
receive link pulses are detected without receipt of a link pulse of the expected polarity. Reversed
polarity is also detected if four frames are received with a reversed start-of-idle. Whenever a
correct polarity frame or a correct link pulse is received, these two counters are reset to zero. If the
LXT901/907 enters the link fail state and no valid data or link pulses are received within 96 to 128
ms, the polarity is reset to the default non-flipped condition. Polarity correction is always enabled.
Collision Detection Function
The collision detection function operates on the twisted pair side of the interface. For standard
(half-duplex) 10BASE-T operation, a collision is defined as the simultaneous presence of valid
signals on both the TPI circuit and the TPO circuit. The LXT901/907 reports collisions to the back-
end via the COL pin. If the TPI circuit becomes active while there is activity on the TPO circuit,
the TPI data is passed to the back-end over the RXD circuit, disabling normal loopback.
a state diagram of the LXT901/907 collision detection function. Refer to Test Specifications for
collision detection and COL/CI output timing.
disabled.)
Universal 10BASE-T and AUI Transceivers — LXT901/907
Figure 6
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is