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Preliminary Spec. ver
1.4
KS8910 100/10 Mbps ETHERNET TRANSCEIVER
SQE FUNCTION
The 10BASE-T transceiver supports the signal quality error (SQE) function as shown in Figure 5-3. If SQE register
is enabled after every successful transmission on the 10BASE-T network, the 10BASE-T transceiver transmits the
SQE signal to the DTE for ten 5 bit times over the internal CI Circuit.
If SQE is disabled, the 10Base-T transceiver does not transmit SQE signal.The default value of SQE register is dis-
able.
DO_active
XMIT_EN
CLK(20MHz)
RECEIVE FUNCTION
The 10BASE-T transceiver receive function acquires timing and data from the twisted-pair network (the TPI cir-
cuit)). Valid received signals are passed through the on-chip filters and Manchester decoder and output as decoded
NRZ data and receive timing on the RXD and RCLK pins, respectively. No external filters are required. An internal
intelligent squelch function discriminates noise from link test pulses and valid data streams. The receive function is
activated only by valid data streams above the squelch level and with proper timing. If the differential signal at the
TPI circuit inputs falls below 75% of the threshold level (unsquelched) for eight bit times (typical), the 10BASE-T
transceiver receive function enters the idle state. If the polarity of the TPI circuit is reversed, the 10BASE-T trans-
ceiver detects the polarity reversal and reports it via the PLR output. The 10BASE-T transceiver automatically cor-
rects reversed polarity.
POLARITY REVERSE FUNCTION
The 10BASE-T transceiver polarity reverse function uses both link pulses and end-of-frame data to determine the
polarity of the received signal. 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 polarity is reversed, these two counters are reset to zero. If the
10BASE-T transceiver 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. If Link Integrity Testing is disabled, polarity detection is based
only on received data. The polarity reverse function can be controlled by B10CR register.
wait 1us after
transmit finished
signal 1us
Generation sqet
Figure 5-2. SQE Function
10BASE-T DIGITAL BLOCKS
sqet_ci_sqe
5-3
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