386SX 25/33 Motherboard Settings and Configuration

Processor	80386SX
Processor Speed	25/33MHz
Chip Set	Unidentified
Max. Onboard DRAM	4MB
Cache	None
BIOS	Unidentified
Dimensions	330mm x 218mm
I/O Options	Floppy drive interface, game port, IDE interface, parallel port, serial ports (2)
NPU Options	80387SX

CONNECTIONS
Purpose	Location	Purpose	Location
Serial port 1	CN1	Reset switch	J2 pin 5
Serial port 2	CN2	Ground	J2 pin 8
Game port	CN3	Speaker	J8
Parallel port	CN4	External battery	J9
IDE interface LED	J1	IDE interface	J10
Power LED & keylock	J2 pin 3	Floppy drive interface	J12
Turbo switch	J2 pin 4	Riser Card	SL1

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	NPU disabled	JP1	pins 1 & 2 closed
	NPU enabled	JP1	pins 2 & 3 closed
»	External battery installed	JP6	pins 1 & 2 closed
	External battery not installed	JP6	pins 2 & 3 closed
»	Parity disabled (3 SIMM motherboard)	JP15	Open
	Parity enabled (4 SIMM motherboard)	JP15	Closed
»	Parallel port IRQ select IRQ7	JP34	pins 1 & 2 closed
	Parallel port IRQ select IRQ5	JP34	pins 2 & 3 closed
»	IDE interface enabled	JP35	pins 2 & 3 closed
	IDE interface disabled	JP35	pins 1 & 2 closed
»	Game port installed	JP42	pins 1 & 2 closed
	Game port not installed	JP42	pins 2 & 3 closed

DRAM CONFIGURATION (WITH BANK 0A FACTORY INSTALLED)
Size	Bank 0a	Bank 1	Bank 2	Bank 3
1MB	(2) 1M x 4	NONE	NONE	NONE
2MB	(2) 1M x 4	(1) 1M x 9	NONE	NONE
4MB	(2) 1M x 4	(1) 1M x 9	(1) 1M x 9	(1) 1M x 9
Note: This configuration is applicable only with Bank O factory installed. The mainboard is manufactured with either 4 SIMM banks or 3 SIMM banks and 2 DRAM banks. The 2 DRAM banks are factory installed and are not configurable.

DRAM JUMPER CONFIGURATION (WITH BANK 0 FACTORY INSTALLED)
Size	JP11-12, JP16, JP19-27
1MB	pins 2 & 3 closed
2MB	pins 2 & 3 closed
4MB	pins 2 & 3 closed
Note: This configuration is applicable only with Bank O factory installed.

DRAM CONFIGURATION (WITH BANK 0 USER INSTALLED)
Size	Bank 0	Bank 1	Bank 2	Bank 3
2MB	(1) 1M x 9	(1) 1M x 9	NONE	NONE
4MB	(1) 1M x 9	(1) 1M x 9	(1) 1M x 9	(1) 1M x 9
Note: This configuration is applicable only with Bank O user installed.

DRAM CONFIGURATION (WITH BANK 0 USER INSTALLED)
Size	JP11-12, JP16, JP19-27
2MB	pins 2 & 3 closed
4MB	pins 2 & 3 closed
Note: This configuration is applicable only with Bank O user installed.

PARALLEL PORT CONFIGURATION
Parallel port	JP30	JP31
LPT1 (0378h)	pins 2 & 3 closed	pins 1 & 2 closed
LPT1 (02BCh)	pins 2 & 3 closed	pins 2 & 3 closed
LPT2 (0278h)	pins 1 & 2 closed	pins 2 & 3 closed

SERIAL PORT 1 CONFIGURATION
Port 1		JP28	JP40
»	COM 1	pins 2 & 3 closed	pins 1 & 2 closed
	COM 3	pins 1 & 2 closed	pins 2 & 3 closed
	COM 4	pins 2 & 3 closed	pins 2 & 3 closed
	Disabled	pins 1 & 2 closed	pins 1 & 2 closed

SERIAL PORT 1 INTERRUPT CONFIGURATION
IRQ		JP32	JP39
»	IRQ4	pins 1 & 2 closed	N/A
	IRQ3	pins 1 & 2 closed	pins 1 & 2 closed

SERIAL PORT 2 CONFIGURATION
Port 2		JP29	JP41
»	COM 2	pins 2 & 3 closed	pins 1 & 2 closed
	COM 3	pins 2 & 3 closed	pins 2 & 3 closed
	COM 4	pins 1 & 2 closed	pins 2 & 3 closed
	Disabled	pins 1 & 2 closed	pins 1 & 2 closed

SERIAL PORT 2 INTERRUPT CONFIGURATION
IRQ		JP32	JP39
»	IRQ3	N/A	pins 1 & 2 closed
	IRQ4	pins 2 & 3 closed	pins 2 & 3 closed

FLOPPY DRIVE CONFIGURATION
Type	JP37	JP44
A = 3.5" & B = 5.25"	pins 2 & 3 closed	pins 2 & 3 closed
A = 5.25" & B = 3.5"	pins 2 & 3 closed	pins 1 & 2 closed

PAGE INTERLEAVE CONFIGURATION
Mode	JP14	JP18
Disabled	pins 1 & 2 closed	pins 2 & 3 closed
Enabled ( requires 4 SIMM configuration)	pins 2 & 3 closed	pins 2 & 3 closed