COM20020_00 Datasheet, PDF (22/82 Pages) SMSC Corporation – Universal Local Area Network Controller with 2K x 8 On-Board RAM

1
1
0
20MHZ
CLOCK
(FOR REF.
ONLY)
100ns
nPULSE1
100ns
nPULSE2
200ns
DIPULSE
RXIN
400ns
FIGURE 6 - DIPULSE WAVEFORM FOR DATA OF 1-1-0
range and common mode noise rejection, for
In typical applications, the serial backplane is example, would require the signals to be
terminated at both ends and a bias is provided by independent of one another.
the external pull-up resistor.
The RXIN signal is directly connected to the cable
via an internal Schmitt trigger. A negative pulse
on this input indicates a logic "1". Lack of pulse
indicates a logic "0". For typical single-ended
backplane applications, RXIN is connected to
nPULSE1 to make the serial backplane data line.
A ground line (from the coax or twisted pair)
should run in parallel with the signal. For
applications requiring different treatment of the
receive signal (like filtering or squelching),
nPULSE1 and RXIN remain as independent pins.
External differential drivers/receivers for increased
22
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