386NSX Motherboard Settings and Configuration

Processor	80386SX
Processor Speed	16/20/25MHz
Chip Set	OPTI
Max. Onboard DRAM	16MB
Cache	None
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	Parallel port, serial ports (2), floppy drive interface, IDE interface, bus mouse port
NPU Options	80387SX

CONNECTIONS
Purpose	Location	Purpose	Location
Serial port 1	J13	Reset switch	J19
Serial port 2	J14	Speaker	J21
Parallel port	J15	Power LED & keylock	J22
IDE interface	J16	Turbo switch	J23 pins 1 & 2
Floppy drive interface	J17	Turbo LED	J23 pins 2 & 3
IDE interface LED	J18	External battery	R1

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Serial port 2 select IRQ3	W1	pins 1 & 2 closed
	Serial port 2 select IRQ9	W1	pins 2 & 3 closed
	Serial port 2 disabled	W1	pins 3 & 4 closed
»	Serial port 1 select IRQ4	W2	pins 1 & 2 closed
	Serial port 1 select IRQ5	W2	pins 2 & 3 closed
	Serial port 1 disabled	W2	pins 3 & 4 closed
»	Parallel IRQ select IRQ7	W3	pins 1 & 2 closed
	Parallel IRQ select IRQ5	W3	pins 2 & 3 closed
	Parallel port select no interrupt	W3	pins 3 & 4 closed
	Flash BIOS reprogram mode enabled	W4	pins 1 & 2 closed
	Flash BIOS reprogram mode disabled	W4	pins 2 & 3 closed
»	Monitor type select color	W5	pins 1 & 2 closed
	Monitor type select monochrome	W5	pins 2 & 3 closed
»	BIOS address line normal operation	W6	pins 2 & 3 closed
	BIOS address line inverted	W6	pins 1 & 2 closed
»	Mouse IRQ select IRQ9	W7	pins 1 & 2 closed
	Mouse IRQ select IRQ5	W7	pins 2 & 3 closed
»	CMOS memory normal operation	W8	pins 1 & 2 closed
	CMOS memory clear	W8	pins 2 & 3 closed
»	Factory configured - do not alter	W9	pins 1 & 2 closed
»	Battery type select internal	W11	Closed
	Battery type select external	W11	Open

DRAM CONFIGURATION
Size	Bank 0	Bank 1	Bank 2	Bank 3
1MB	(2) 256K x 9	(2) 256K x 9	NONE	NONE
2MB	(2) 256K x 9	(2) 256K x 9	(2) 256K x 9	(2) 256K x 9
2MB	(2) 1M x 9	NONE	NONE	NONE
3MB	(2) 256K x 9	(2) 256K x 9	(2) 1M x 9	NONE
4MB	(2) 1M x 9	(2) 1M x 9	NONE	NONE
5MB	(2) 256K x 9	(2) 256K x 9	(2) 1M x 9	(2) 1M x 9
6MB	(2) 1M x 9	(2) 1M x 9	(2) 1M x 9	NONE
8MB	(2) 1M x 9	(2) 1M x 9	(2) 1M x 9	(2) 1M x 9
9MB	(2) 256K x 9	(2) 256K x 9	(2) 4M x 9	NONE
10MB	(2) 1M x 9	(2) 4M x 9	NONE	NONE
12MB	(2) 1M x 9	(2) 1M x 9	(2) 4M x 9	NONE
16MB	(2) 4M x 9	(2) 4M x 9	NONE	NONE

CPU SPEED CONFIGURATION
Size	W9	W10
16MHz	pins 2 & 3 closed	Open
20MHz	pins 1 & 2 closed	pins 1 & 2 closed
25MHz	pins 1 & 2 closed	pins 2 & 3 closed