5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
PLCC PIN
NO.
NAME
nTransmit
SYMBOL
nTXEN
DESCRIPTION
21
Output. This signal is used prior to the Power-up to enable
the line drivers for transmission. The polarity of the signal
is programmable through the nPULSE2 pin.
nEnable
nPULSE2 floating before Power-up: nTXEN active low
(Default option)
nPULSE2 grounded before Power-up: nTXEN active high
(This option is only available in Backplane Mode)
16,17
Crystal
XTAL1,
XTAL2
An external crystal should be connected to these pins.
Oscillation frequency range is from 10 to 20 MHz. If an
external TTL clock is used instead, it must be connected to
XTAL1 with a 390Ω pull-up resistor, and XTAL2 should be
left floating.
Oscillator
15,28
Power
Supply
Ground
VDD
VSS
+5 Volt Power Supply pin.
7,14,22
Ground pin.
Revision 12-05-06
Page 10
SMSC COM20020I Rev D
DATASHEET
SMSC [ SMSC CORPORATION ]
