SMC Networks 486DX4 - Manual (Page 25)

AR-B1462 User¡ ¦s Guide
3-7
Name Description
-MASTER [Input] The MASTER is the signal from the I/O processor which
gains control as the master and should be held low for a
maximum of 15 microseconds or system memory may be
lost due to the lack of refresh
-MEMCS16
[Input, Open collector]
The Memory Chip Select 16 indicates that the present data
transfer is a 1-wait state, 16-bit data memory operation
-IOCS16
[Input, Open collector]
The I/O Chip Select 16 indicates that the present data
transfer is a 1-wait state, 16-bit data I/O operation
OSC [Output] The Oscillator is a 14.31818 MHz signal used for the color
graphic card
-ZWS
[Input, Open collector]
The Zero Wait State indicates to the microprocessor that
the present bus cycle can be completed without inserting
additional wait cycle
Table 3-2 I/O Channel Signal’ s Description
3.2.5 LED Header (LM1)
The AR-B1462 provides one module for various LEDs’ headers.
1
4
2
7
5
3
8
6
+5V Power LED Header
Watchdog LED Header
LAN LED Header
HDD LED Header
LM1
Figure 3-10 LM1: LED Header
3.2.6 Serial Port
(1) RS-422/RS-485 Select
SW1-9 & SW1-10 selects COM B port, and adjusts the CN15 connector is RS-485 or RS-232C. M5 selects COM A
port for using DB2 for RS-232C or connects External RS-485.
(A) COM-A RS-485/RS-422 Adapter Select (M5)
A B C
3
2
1
RS-422
Factory Preset
A B C
3
2
1
RS-485
Figure 3-11 M5: COM-A RS-485/RS-422 Adapter Select
(B) Terminal Select (M5)
OFF
1
2
3
ON
1
2
3
Factory-Default Setting
C B A C B A
Figure 3-12 M5: Terminal Select