XTAL1
XTAL2
COM20020-5
AD0-AD7
ALE
AD0-AD2, D3-D7
A2/BALE
nCS
RXIN
A15
75ALS176B
or Equiv.
RESET
nRESET IN
nTXEN
nPULSE1
nPULSE2
nRD/nDS
nRD
nWR/DIR
nINTR
nWR
GND
nINT1
Differential Driver
Configuration
AO/nMUX
*
Media Interface
may be replaced
XTAL
XTAL
2
1
with Figure A, B or C.
8051
40 MHz
47 pF
47 pF
1K
FIGURE 2 - MULTIPLEXED, 8051-LIKE BUS INTERFACE WITH RS-485 INTERFACE
+5V
2
RXIN
+5V
Receiver
HFD3212-002
6
RXIN
7
100 Ohm
TXEN
Transmitter
HFE4211-014
nPULSE1
nPULSE2
GND
3
nPULSE1
+5V
2
6
7
2 Fiber Interface
(ST Connectors)
NOTE: COM20020-5 must be in Backplane Mode
BACKPLANE CONFIGURATION
FIGURE A
FIGURE B
13