SCI 486SX/DX SYSTEM BOARD Motherboard Settings and Configuration

Processor	80486SX/80486DX
Processor Speed	25/33MHz
Chip Set	OPTI
Max. Onboard DRAM	64MB
Cache	64/256KB
BIOS	Unidentified
Dimensions	330mm x 218mm
I/O Options	Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA port
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
PS/2 mouse port	J1	IDE interface LED	J23
IDE interface	J5	Reset switch	J24
Floppy drive interface	J6	Speaker	J25
Parallel port	J8	Power LED & keylock	J26
Serial port 2	J9	VGA port	J27
Serial port 1	J10

USER CONFIGURABLE SETTINGS
Function		Jumper/Switch	Position
»	Monitor type select color	W1	pins 1 & 2 closed
	Monitor type select monochrome	W1	pins 2 & 3 closed
»	CMOS memory normal operation	W2	pins 1 & 2 closed
	CMOS memory clear	W2	pins 2 & 3 closed
»	SYSCLK enabled	W3	pins 2 & 3 closed
	SYSCLK/2 enabled	W3	pins 1 & 2 closed
»	On board VGA enabled	W10	pins 1 & 2 closed
	On board VGA disabled	W10	pins 2 & 3 closed
»	Video horizontal scan rate select 31.5 kHz	SW1/5	On
	Video horizontal scan rate select 40kHz	SW1/5	Off
»	Video memory select 512KB	SW1/6	On
	Video memory select 1MB	SW1/6	Off

DRAM CONFIGURATION
Size	Bank 0	Bank 1	Bank 2	Bank 3
1MB	(1) 256K x 36	NONE	NONE	NONE
2MB	(1) 256K x 36	(1) 256K x 36	NONE	NONE
4MB	(1) 1M x 36	NONE	NONE	NONE
5MB	(1) 256K x 36	(1) 1M x 36	NONE	NONE
6MB	(1) 256K x 36	(1) 256K x 36	(1) 1M x 36	NONE
8MB	(1) 1M x 36	(1) 1M x 36	NONE	NONE
9MB	(1) 256K x 36	(1) 1M x 36	(1) 1M x 36	NONE
10MB	(1) 256K x 36	(1) 256K x 36	(1) 1M x 36	(1) 1M x 36
12MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	NONE
13MB	(1) 256K x 36	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36
16MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36
16MB	(1) 4M x 36	NONE	NONE	NONE
20MB	(1) 1M x 36	(1) 4M x 36	NONE	NONE
20MB	(1) 4M x 36	(1) 1M x 36	NONE	NONE
24MB	(1) 1M x 36	(1) 1M x 36	(1) 4M x 36	NONE
24MB	(1) 1M x 36	(1) 4M x 36	(1) 1M x 36	NONE
24MB	(1) 4M x 36	(1) 1M x 36	(1) 1M x 36	NONE
28MB	(1) 1M x 36	(1) 1M x 36	(1) 4M x 36	(1) 1M x 36
28MB	(1) 1M x 36	(1) 4M x 36	(1) 1M x 36	(1) 1M x 36
28MB	(1) 4M x 36	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36
32MB	(1) 4M x 36	(1) 4M x 36	NONE	NONE
36MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	NONE
36MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	NONE
36MB	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36	NONE
40MB	(1) 1M x 36	(1) 1M x 36	(1) 4M x 36	(1) 4M x 36
40MB	(1) 1M x 36	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36
40MB	(1) 4M x 36	(1) 1M x 36	(1) 4M x 36	(1) 1M x 36
40MB	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36	(1) 1M x 36

DRAM CONFIGURATION (CON’T)
Size	Bank 0	Bank 1	Bank 2	Bank 3
48MB	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36	NONE
52MB	(1) 1M x 36	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36
52MB	(1) 4M x 36	(1) 1M x 36	(1) 4M x 36	(1) 4M x 36
52MB	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36
64MB	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36

CACHE CONFIGURATION
Size	Bank 0	Bank 1	TAG
64KB	(4) 8K x 8	(4) 8K x 8	(2) 16K x 4
256KB	(4) 32K x 8	(4) 32K x 8	(2) 16K x 4

CACHE JUMPER CONFIGURATION
Size	W4	W5	W9	W11
64KB	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed
256KB	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed

CPU TYPE CONFIGURATION
Type	W6	W7	W8
486SX	pins 2 & 3 closed	pins 2 & 3 closed	N/A
487SX	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed
486DX	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed

VIDEO CONFIGURATION (800 X 600)
Refresh rate		SW1/1	SW1/2
»	60Hz	Off	On
	56Hz	Off	Off
	56Hz	On	On
	72Hz	On	Off

VIDEO CONFIGURATION (1024 X 768)
Refresh rate		SW1/3	SW1/4
»	Interlaced	Off	Off
	60Hz	Off	On
	70Hz	On	Off
	72Hz	On	On

VIDEO MEMORY CONFIGURATION
Size	Bank 0	Bank 1
512KB	(4) 256K x 4	NONE
1MB	(4) 256K x 4	(4) 256K x 4
Note: Bank 0 is factory installed and is not configurable.