CS8904
Crystal LAN™ Quad Ethernet Transceiver
If the remote device supports Auto-Negotiation,
To detect a reversed pair, the receiver examines
but does not share a compatible set of capabilities received link pulses and the End-of-Frame (EOF)
with the CS8904, then the CS8904 will indicate sequence of incoming packets. If it detects at least
that the Auto-Negotiation was unsuccessful and one reversed link pulse and at least four frames in a
that the link is failed through the Auto-Negotiation row with negative polarity after the EOF, the
output and the Link Status LED output. Auto-
receive pair is considered reversed. Any data
negotiation may also fail if the CS8904 is unable to received before the correction of the reversal is
exchange a Link Code Word with the remote
device.
ignored.
3.3.4 Collision Detection
When Auto-Negotiation is disabled, the CS8904
sends Normal Link Pulses to the remote Ethernet
device.
If half duplex operation is selected, the CS8904
detects a 10BASE-T collision whenever the
receiver and transmitter are active simultaneously.
When a collision is present, the collision detection
circuit informs the digital controller by asserting
the collision signal. If full duplex operation is
selected, the collision detection circuit is disabled.
3.3.3.3 Receive Polarity Detection and Correction
The CS8904 checks the polarity of the receive half
of the twisted pair cable and automatically corrects
a reversal.
CIRRUS LOGIC ADVANCED PRODUCT DATABOOK
DS191PP2
15
CIRRUS [ CIRRUS LOGIC ]
