10 Mbps ARCNET (ANSI 878.1) Controller with 2Kx8 On-Board RAM
Datasheet
PIN NO
24
NAME
nPulse 1
25
nPulse 2
28
29
Receive In
nTransmit
Enable
21
22
Crystal
Oscillator
8,20,
32,43
6,11,
18,23,
30,41
19,27
Power
Supply
Ground
SYMBOL
I/O
DESCRIPTION
TRANSMISSION MEDIA INTERFACE
nPULSE1
OUT
In Normal Mode, these active low signals carry the transmit
data information, encoded in pulse format as DIPULSE
waveform. In Backplane Mode, the nPULSE1 signal driver
is programmable (push/pull or open-drain), while the
nPULSE2
I/O
nPULSE2 signal provides a clock with frequency of doubled
data rate. nPULSE1 is connected to a weak internal pull-up
resistor on the open/drain driver in backplane mode.
RXIN
IN
This signal carries the receive data information from the line
transceiver.
nTXEN
OUT
Transmission Enable signal. Active polarity is
programmable through the nPULSE2 pin.
nPULSE2 floating before power-up;
nTXEN active low
nPULSE2 grounded before power-up;
nTXEN active high (this option is only available in Back
Plane mode)
XTAL1
IN
An external crystal should be connected to these pins.
Oscillation frequency range is from 10 MHz to 20 MHz. If
XTAL2
OUT
an external TTL clock is used instead, it must be connected
to XTAL1 with a 390ohm pull-up resistor, and XTAL2 should
be left floating.
VDD
PWR
+5 Volt power supply pins.
VSS
PWR
Ground pins.
N/C
N/C
Non-connection
SMSC COM20022I
Page 9
Revision 02-27-06
DATASHEET
SMSC [ SMSC CORPORATION ]
