ASC486 VER. C Motherboard Settings and Configuration

Processor	80486SX/CX486S/80487SX/CX486S2/80486DX/80486DX2/Pentium Overdrive
Processor Speed	25/33/40/50(internal)/50/66(internal)MHz
Chip Set	ALI
Max. Onboard DRAM	128MB
Cache	32/64/128/256/512/1024KB
BIOS	AMI
Dimensions	312mm x 122mm
I/O Options	Floppy drive interface, IDE interface, parallel port, serial ports (2)
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
Keyboard connector	CN1	Serial port 1	CN9
Power LED & keylock	CN2	Serial port 2	CN10
Floppy drive interface	CN3	Speaker	JP1
IDE interface LED	CN4	Reset switch	JP2
Parallel port	CN5	IDE interface	JP3
PC/104 Module connector	CN6	Turbo switch	JP4
Keyboard port	CN7	Turbo LED	JP5

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Battery type select external	JP11	pins 2 & 3 closed
	Battery type select internal	JP11	pins 1 & 2 closed
»	Clock system select double frequency	JP15 & JP46	pins 1 & 2 closed
	Clock system select single frequency	JP15 & JP46	pins 2 & 3 closed
»	CMOS memory normal operation	JP28	Open
	CMOS memory clear	JP28	Closed
»	Parallel port interrupt select IRQ7	JP31	pins 1 & 2 closed
	Parallel port interrupt select IRQ5	JP31	pins 2 & 3 closed
»	IDE interface enabled	JP32	pins 1 & 2 closed
	IDE interface disabled	JP32	pins 2 & 3 closed
»	Parallel port address select 378h-37Fh	JP33	pins 1 & 2 closed
	Parallel port address select 278h-27Fh	JP33	pins 2 & 3 closed
»	Floppy drive interface enabled	JP34	pins 1 & 2 closed
	Floppy drive interface disabled	JP34	pins 2 & 3 closed
»	Monitor type select color	JP38	Closed
	Monitor type select monochrome	JP38	Open
»	Parallel port unidirectional	JP39	Closed
	Parallel port bidirectional	JP39	Open
»	XT IDE interface disabled	JP40	pins 2 & 3 closed
	XT IDE interface enabled	JP40	pins 1 & 2 closed
»	Parallel port enabled	JP43	pins 1 & 2 closed
	Parallel port disabled	JP43	pins 2 & 3 closed

SERIAL PORT CONFIGURATION
Port 1 (CN9)	Port 2 (CN10)	JP41	JP42	JP44	JP45
3F8h-3FFh	2F8h-2FFh	1 & 2	1 & 2	1 & 2	1 & 2
3F8h-3FFh	Disabled	1 & 2	1 & 2	N/A	2 & 3
Disabled	2F8h-2FFh	2 & 3	N/A	1 & 2	1 & 2
3E8h-3EFh	2E8h-2EFh	1 & 2	2 & 3	2 & 3	1 & 2
3E8h-3EFh	Disabled	1 & 2	2 & 3	N/A	2 & 3
Disabled	2E8h-2EFh	2 & 3	N/A	2 & 3	1 & 2
Disabled	Disabled	2 & 3	N/A	N/A	2 & 3
Note: Pins designated should be in the closed position.

SERIAL PORT INTERRUPT SELECT
Port 1 (CN9)	Port 2 (CN10)	JP29	JP30
IRQ4	IRQ3	pins 1 & 2 closed	pins 2 & 3 closed
IRQ3	IRQ4	pins 2 & 3 closed	pins 1 & 2 closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1
1MB	(4) 256K x 9	NONE
2MB	(4) 256K x 9	(4) 256K x 9
3MB	(4) 256K x 9	(4) 256K x 9
4MB	(4) 1M x 9	NONE
8MB	(4) 1M x 9	(4) 1M x 9
16MB	(4) 4M x 9	NONE
20MB	(4) 1M x 9	(4) 4M x 9
32MB	(4) 4M x 9	(4) 4M x 9
64MB	(4) 16M x 9	NONE
128MB	(4) 16M x 9	(4) 16M x 9

CACHE CONFIGURATION
Size	Bank 0	Bank 1	TAG
32KB	(4) 8K x 8	NONE	(1) 16K x 4
64KB	(4) 8K x 8	(4) 8K x 8	(1) 16K x 4
128KB	(4) 32K x 8	NONE	(1) 32K x 8
256KB	(4) 32K x 8	(4) 32K x 8	(1) 32K x 8
512KB	(4) 128K x 8	NONE	(1) 64K x 4
1MB	(4) 128K x 8	(4) 128K x 8	(1) 64K x 4

CACHE JUMPER CONFIGURATION
Size	JP22
32KB	Open
64KB	pins 9 & 10 closed
128KB	pins 7 & 8, 9 & 10 closed
256KB	pins 5 & 6, 7 & 8, 9 & 10 closed
512KB	pins 3 & 4, 5 & 6, 7 & 8, 9 & 10 closed
1MB	pins 1 & 2, 3 & 4, 5 & 6, 7 & 8, 9 & 10 closed

CACHE JUMPER CONFIGURATION (CON’T)
Size	JP24	JP25	JP26	JP27
32KB	Open	Open	pins 2 & 3 closed	pins 1 & 2 closed
64KB	Open	Open	pins 1 & 2 closed	pins 1 & 2 closed
128KB	Open	pins 2 & 3 closed	pins 1 & 2 closed	pins 2 & 3 closed
256KB	Open	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed
512KB	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed
1MB	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed

CPU TYPE CONFIGURATION
Type	JP6	JP7	JP8	JP12	JP13	JP14
80486SX	1 & 2	1 & 2	1 & 2	1 & 2	1 & 2	1 & 2
80487SX	1 & 2	1 & 2	2 & 3	1 & 2	1 & 2	1 & 2
CX486S	1 & 2	1 & 2	1 & 2	1 & 2	2 & 3	2 & 3
CX486S2	2 & 3	1 & 2	1 & 2	1 & 2	1 & 2	2 & 3
80486DX/DX2	1 & 2	1 & 2	2 & 3	1 & 2	1 & 2	1 & 2
Overdrive	2 & 3	2 & 3	2 & 3	2 & 3	1 & 2	1 & 2
Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION (CON’T)
Type	JP16	JP17	JP18	JP19	JP20	JP21
80486SX	Open	Open	Closed	Open	Open	Open
80487SX	1 & 2	Open	Closed	Open	Open	Closed
CX486S	3 & 4	Open	Open	Closed	Closed	Open
CX486S2	3 & 4	Closed	Open	Closed	Closed	Open
80486DX/DX2	2 & 3	Open	Closed	Open	Open	Closed
Overdrive	1 & 2	Closed	Closed	Open	Open	Closed
Note: Pins designated should be in the closed position.

CPU SPEED CONFIGURATION (EXTERNAL)
Speed	JP23/1 & 2	JP23/3 & 4	JP23/5 & 6	JP23/7 & 8
25MHz	Open	Open	Open	Closed
33MHz	Closed	Open	Open	Open
40iMHz	Closed	Closed	Closed	Open
40MHz	Closed	Closed	Open	Open
50iMHz	Open	Closed	Open	Open
50MHz	Open	Open	Closed	Closed
66iMHz	Closed	Open	Closed	Open
Overdrive	Open	Closed	Closed	Open

CPU SPEED CONFIGURATION (INTERNAL)
Speed	JP9	JP10
40iMHz	pins 1 & 2 closed	pins 2 & 3 closed
50iMHz	pins 2 & 3 closed	pins 2 & 3 closed
66iMHz	pins 2 & 3 closed	pins 1 & 2 closed

WATCH DOG TIMER SETTING
Setting	JP35
Reset when WDT time out	pins 1 & 2 closed
Activate NMI to CPU when WDT time out	pins 2 & 3 closed
WDT disabled	Open

WATCH DOG TIME OUT PERIOD
Time out period	JP36	JP37
500ms	pins 1 & 2 closed	Closed
1 second	pins 1 & 2 closed	Open
2.5 seconds	pins 2 & 3 closed	Closed
5 seconds	pins 2 & 3 closed	Open