DC 486 EISA Motherboard Settings and Configuration

Processor	80486SX/80487SX/80486DX/80486DX2
Processor Speed	20/25/33/50(internal)/50/66(internal)MHz
Chip Set	OPTI
Max. Onboard DRAM	128MB
Cache	64/128/256KB
BIOS	AMI
Dimensions	330.2mm x 218.4mm
I/O Options	None
NPU Options	4167

CONNECTIONS
Purpose	Location	Purpose	Location
Speaker	J4	Reset switch	S9
Power LED & keylock	J5	Turbo switch	SW
Turbo LED	LED

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Monitor type select color	JP4	closed
	Monitor type select monochrome	JP4	open
»	CPU speed select 25/33/50MHz	JP6	open
	CPU speed select 20MHz	JP6	closed
»	CPU speed select iOSC/1	JP8	pins 1 & 2 closed
	CPU speed select iOSC/2	JP8	pins 2 & 3 closed

EISA BUS CONTROLLER SPEED SELECT
Speed	JP1	JP2	JP3
20MHz	open	closed	pins 2 & 3 closed
25MHz	open	open	pins 1 & 2 closed
33MHz	closed	open	pins 1 & 2 closed
40MHz	open	closed	pins 1 & 2 closed
50Mhz	closed	closed	pins 1 & 2 closed

CPU TYPE CONFIGURATION
Jumper	80486SX	80487SX	80486DX or DX2
JP7	pins 2 & 3 closed	pins 1 & 2 and 3 & 4 closed	pins 1 & 2 and 3 & 4 closed
JP9	open	pins 1 & 2 closed	pins 2 & 3 closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1
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
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 JUMPER CONFIGURATION
Jumper	64KB	128KB	256KB
JP5	pins 2 & 3 closed	pins 1 & 2 closed	pins 2 & 3 closed
JP10	open	open	open
JP11	open	open	closed
JP12	open	closed	closed
JP13	open	open	closed
JP14	open	closed	closed
JP15	open	open	open

CACHE CONFIGURATION
Size	Cache	Location	TAG (U49)	TAG (U50)	TAG (U51)	Dirty bit (U64)
64KB	(8) 8K x 8	Banks 0 & 1	(1) 4K x 1	(1) 8K x 8	NONE	(1) 64K x 1
128KB	(4) 32K x 8	Bank 0	(1) 64K x 1	(1) 8K x 8	NONE	(1) 64K x 1
256KB	(8) 32K x 8	Banks 0 & 1	(1) 64K x 1	(1) 8K x 8	(1) 8K x 8	(1) 64K x 1