VESA MAINBOARD SIS 486 (REV. 2) Motherboard Settings and Configuration

Processor	80486SX/CX486M7/80486DX/80486DX2/Pentium Overdrive
Processor Speed	25/33/40/50(internal)/50/66(internal)MHz
Chip Set	SIS
Max. Onboard DRAM	128MB
Cache	128/256/512KB
BIOS	AMI/Award
Dimensions	330mm x 218mm
I/O Options	32-bit VESA local bus slots (3), green PC connector
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
External battery	J1	Reset switch	J6
Turbo switch	J3	Power LED & keylock	J7
Turbo LED	J4	Green PC connector	JP26
Speaker	J5	32-bit VESA local bus slots	SL1 - SL3

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	SMOUT type select normal mode	J2	Closed
	SMOUT type select standby mode	J2	Open
»	CMOS memory normal operation	JP16	pins 1 & 2 closed
	CMOS memory clear	JP16	pins 2 & 3 closed
»	Factory configured - do not alter	JP18	Open

DRAM CONFIGURATION
Size	Bank 0	Bank 1
1MB	(4) 256K x 9	NONE
2MB	(4) 256K x 9	(4) 256K x 9
4MB	(4) 1M x 9	NONE
5MB	(4) 256K x 9	(4) 1M x 9
8MB	(4) 1M x 9	(4) 1M x 9
16MB	(4) 4M x 9	NONE
17MB	(4) 256K x 9	(4) 4M x 9
20MB	(4) 1M x 9	(4) 4M x 9
32MB	(4) 4M x 9	(4) 4M x 9
64MB	(4) 16M x 9	NONE
65MB	(4) 256K x 9	(4) 16M x 9
68MB	(4) 1M x 9	(4) 16M x 9
80MB	(4) 4M x 9	(4) 16M x 9
128MB	(4) 16M x 9	(4) 16M x 9

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

CACHE JUMPER CONFIGURATION
Size	JP1	JP2	JP3	JP4
128KB	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed
256KB	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3, 4 & 5 closed	pins 1 & 2 closed
512KB	pins 1 & 2 closed	pins 2 & 3 closed	pins 1 & 2, 3 & 4 closed	pins 2 & 3 closed

CPU TYPE CONFIGURATION
Type	JP8	JP9	JP10	JP11	JP12	JP13	JP14
80486SX	2 & 3	Open	2 & 3	Open	3 & 4	1 & 2	2 & 3
CX486M7	1 & 2	Closed	2 & 3	2 & 3	2 & 3	Open	1 & 2
80486DX/DX2	1 & 2	Closed	2 & 3	2 & 3	3 & 4	1 & 2	2 & 3
P23S	2 & 3	Open	2 & 3	Open	3 & 4	1 & 2	2 & 3
P24D	1 & 2	Closed	1 & 2	2 & 3	1 & 2	2 & 3	2 & 3
P24S	1 & 2	Closed	2 & 3	2 & 3	3 & 4	1 & 2	2 & 3
P24T	1 & 2	Closed	1 & 2	1 & 2	3 & 4	Open	1 & 2
Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION (CON’T)
Type	JP15	JP21	JP22	JP24	JP25	JP30
80486SX	4 & 5	2 & 3	1 & 2	Open	Open	Open
CX486M7	2 & 3	1 & 2	2 & 3	2 & 3	2 & 3	Open
80486DX/DX2	4 & 5	2 & 3	1 & 2	Open	Open	Open
P23S	4 & 5	2 & 3	1 & 2	Open	Open	Open
P24D	4 & 5	2 & 3	1 & 2	Open	1 & 2	Closed
P24S	4 & 5	2 & 3	1 & 2	Open	Open	Open
P24T	1 & 2	1 & 2	1 & 2	1 & 2	1 & 2	Open
Note: Pins designated should be in the closed position.

CPU SPEED CONFIGURATION
Speed	JP5	JP6	JP7
25MHz	Open	Closed	Open
33MHz	Closed	Closed	Closed
40MHz	Open	Closed	Closed
50iMHz	Open	Closed	Open
50MHz	Closed	Open	Open
66iMHz	Closed	Closed	Closed

CPU CLOCK DELAY CONFIGURATION
Delay	JP20
0 delay	pins 1 & 2 closed
1 gate buffer delay	pins 2 & 3 closed

CPU INPUT FREQUENCY CONFIGURATION
input	JP23
Single input	pins 1 & 2 closed
Double input	pins 2 & 3 closed

VESA WAIT STATE CONFIGURATION
Wait states	JP28
0 wait states	pins 1 & 2 closed
1 wait state	pins 2 & 3 closed

BUS SPEED CONFIGURATION
CPU speed	JP29
<= 33MHz	pins 1 & 2 closed
> 33MHz	pins 2 & 3 closed