C426 486DX-33 50/N426 486SX-20 25 Motherboard Settings and Configuration

Processor	80486SX/80486DX
Processor Speed	20/25/33/50MHz
Chip Set	SIS
Max. Onboard DRAM	32MB
Cache	64/128/256KB
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	None
NPU Options	4167

CONNECTIONS
Purpose	Location	Purpose	Location
External battery	J1	Turbo LED	J4
Speaker	J2	Turbo switch	J5
Reset switch	J3	Power LED & keylock	J7

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Keyboard clock select fixed at 7.159MHz	JP2	pins 2 & 3 closed
	Keyboard clock select programmable via BIOS setup	JP2	pins 1 & 2 closed
»	CMOS memory normal operation	JP3	pins 1 & 2 closed
	CMOS memory clear	JP3	pins 2 & 3 closed
»	Monitor type select color	J6	Closed
	Monitor type select monochrome	J6	Open
»	Power good signal detect from board	JP8	pins 1 & 2 closed
	Power good signal detect from power supply	JP8	pins 2 & 3 closed
»	CPU clock speed select ³	JP16	pins 1 & 2 closed
	CPU clock speed select < 25Mz	JP16	pins 2 & 3 closed

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
8MB	(4) 1M x 9	(4) 1M x 9
16MB	(4) 4M x 9	NONE
32MB	(4) 4M x 9	(4) 4M x 9

CACHE CONFIGURATION
Size	Bank 0	Bank 1	TAG	Dirty bit U22
64KB	(4) 8K x 8	(4) 8K x 8	(1) 8K x 8	(1) 16K x 4
128KB	(4) 32K x 8	NONE	(1) 8K x 8	(1) 16K x 4
256KB	(4) 32K x 8	(4) 32K x 8	(1) 32K x 8	(1) 16K x 4

CACHE JUMPER CONFIGURATION
Size	JP9	JP10	JP11	JP12	JP13	JP14	JP15
64KB	1 & 2	2 & 3	1 & 2	1 & 2	1 & 2	1 & 2	1 & 2
128KB	2 & 3	1 & 2	1 & 2	2 & 3	1 & 2	2 & 3	1 & 2
256KB	2 & 3	2 & 3	2 & 3	2 & 3	2 & 3	2 & 3	2 & 3
Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION
Type	JP5	JP6	JP7
80486SX	pins 2 & 3 closed	pins 2 & 3 closed	Open
80487SX	pins 1 & 2 closed	pins 2 & 3 closed	Closed
80486DX	pins 1 & 2 closed	pins 1 & 2 closed	Closed