5Mbps ARCNET (ANSI 878.1) Controller with 2K x 8 On-Chip RAM
Datasheet
XTAL1
XTAL2
COM20020ID
AD0-
AD0-AD2, D3-
ALE
A15
A2/BAL
nCS
RXIN
75176B or
Equiv.
RESET
nRESET
nTXEN
nPULSE
nPULSE
nRD/nD
nRD
nWR/DI
nINTR
nWR
nINT1
GND
Differential
Configuratio
8051
Media
may be
*
XTAL1
XTAL2
A0/nMU
27 pF
with Figure A, B or
27 pF
20 MHz
XTAL
+5V
2
RXIN
+5V
100
Receive
HFD3212-
6
RXIN
7
TXEN
Transmitte
HFE4211-
nPULSE
nPULSE
GND
3
nPULSE
+5V
2
6
7
2 Fiber
(ST
BACKPLANE
NOTE: COM20020 must be in backplane mode
FIGURE B
FIGURE A
Figure 5.1 – Multiplexed, 8051-Like Bus Interface with RS-485 Interface
Revision 12-05-06
Page 18
SMSC COM20020I Rev D
DATASHEET