CHICONY, INC.

CH-491K

Processor	CX486S/80486SX/80487SX/CX486DX/80486DX/CX486DX2/80486DX2/ 80486DX4/Pentium Overdrive
Processor Speed	20/25/33/40/50(internal)/50/66(internal)/75(internal)/100(internal)MHz
Chip Set	SiS
Max. Onboard DRAM	64MB
Cache	32/64/128/256KB
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	32-bit VESA local bus slots (3)
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
External battery	J3	Speaker	J7
Reset switch	J4	Power LED & keylock	J8
Turbo switch	J5	32-bit VESA local bus slots	SL1 - SL3
Turbo LED	J6

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	Battery type select internal	J3	pins 2 & 3 closed
	Battery type select external	J3	Closed
»	CMOS memory normal operation	JP1	Open
	CMOS memory clear	JP1	Closed
»	Address strobe delay disabled	JP7	pins 1 & 2 closed
	Address strobe delay enabled	JP7	pins 2 & 3 closed
»	VESA card type select normal	JP19	pins 1 & 2 closed
	VESA card type select Weitek Power 9000 only	JP19	pins 2 & 3 closed
»	Cyrix C6 not installed	JP20	Open
	Cyrix C6 installed	JP20	Closed

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
2MB	(1) 512K x 36	NONE	NONE	NONE
3MB	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36	NONE
4MB	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36
4MB	(1) 512K x 36	(1) 512K 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) 512K x 36	(1) 1M x 36	NONE	NONE
6MB	(1) 1M x 36	(1) 256K x 36	(1) 256K x 36	NONE
7MB	(1) 256K x 36	(1) 512K x 36	(1) 1M x 36	NONE
7MB	(1) 1M x 36	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36
8MB	(1) 1M x 36	(1) 1M x 36	NONE	NONE
8MB	(1) 2M x 36	NONE	NONE	NONE
9MB	(1) 1M x 36	(1) 1M x 36	(1) 256K x 36	NONE
9MB	(1) 2M x 36	(1) 256K x 36	NONE	NONE
10MB	(1) 1M x 36	(1) 1M x 36	(1) 256K x 36	(1) 256K x 36
12MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	NONE
13MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	(1) 256K x 36
16MB	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36	(1) 1M x 36
16MB	(1) 2M x 36	(1) 2M x 36	NONE	NONE
16MB	(1) 4M x 36	NONE	NONE	NONE
17MB	(1) 4M x 36	(1) 256K x 36	NONE	NONE
18MB	(1) 4M x 36	(1) 256K x 36	(1) 256K x 36	NONE
18MB	(1) 4M x 36	(1) 512K x 36	NONE	NONE
19MB	(1) 4M x 36	(1) 256K x 36	(1) 256K x 36	(1) 256K x 36
20MB	(1) 4M x 36	(1) 1M x 36	NONE	NONE
21MB	(1) 4M x 36	(1) 1M x 36	(1) 256K x 36	NONE
22MB	(1) 4M x 36	(1) 1M x 36	(1) 256K x 36	(1) 256K x 36
32MB	(1) 4M x 36	(1) 4M x 36	NONE	NONE
32MB	(1) 8M x 36	NONE	NONE	NONE

DRAM CONFIGURATION (CON’T)
Size	Bank 0	Bank 1	Bank 2	Bank 3
33MB	(1) 4M x 36	(1) 4M x 36	(1) 256K x 36	NONE
33MB	(1) 8M x 36	(1) 256K x 36	NONE	NONE
34MB	(1) 4M x 36	(1) 4M x 36	(1) 256K x 36	(1) 256K x 36
34MB	(1) 8M x 36	(1) 512K x 36	NONE	NONE
36MB	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36	NONE
36MB	(1) 8M x 36	(1) 1M x 36	NONE	NONE
40MB	(1) 4M x 36	(1) 4M x 36	(1) 1M x 36	(1) 1M x 36
48MB	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36	NONE
64MB	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36	(1) 4M x 36
64MB	(1) 8M x 36	(1) 8M x 36	NONE	NONE
64MB	(1) 16M x 36	NONE	NONE	NONE

DRAM JUMPER CONFIGURATION
Size	JP21	JP22
Double sided SIMM	pins 1 & 2 closed	pins 1 & 2 closed
16MB x 36 SIMM	pins 2 & 3 closed	pins 2 & 3 closed

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

CACHE JUMPER CONFIGURATION
Size	JP2	JP3	JP4	JP5	JP6
32KB	2 & 3	2 & 3	Open	Open	Open
64KB	1 & 2	1 & 2	Open	Open	Closed
128KB	2 & 3	2 & 3	Open	Closed	Closed
256KB	1 & 2	1 & 2	Closed	Closed	Closed
Note: Pins designated should be in the closed position.

CPU TYPE CONFIGURATION
Type	JP15	JP16	JP17
CX486S	pins 2 & 3 closed	Open	Open
80486SX	pins 2 & 3 closed	Open	Open
80487SX	pins 1 & 2, 3 & 4 closed	pins 2 & 3 closed	Open
CX486DX	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed	Open
80486DX	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed	Open
CX486DX2	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed	Closed
80486DX2	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed	Open
80486DX4	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed	Open
Pentium Overdrive	pins 1 & 2, 3 & 4 closed	pins 1 & 2 closed	Open

CPU SPEED CONFIGURATION
Speed	JP8	JP9	JP10
20MHz	pins 1 & 2 closed	pins 2 & 3 closed	pins 2 & 3 closed
25MHz	pins 2 & 3 closed	pins 1 & 2 closed	pins 2 & 3 closed
33MHz	pins 2 & 3 closed	pins 2 & 3 closed	pins 1 & 2 closed
40MHz	pins 1 & 2 closed	pins 1 & 2 closed	pins 2 & 3 closed
50iMHz	pins 2 & 3 closed	pins 1 & 2 closed	pins 2 & 3 closed
50MHz	pins 1 & 2 closed	pins 2 & 3 closed	pins 1 & 2 closed
66iMHz	pins 2 & 3 closed	pins 2 & 3 closed	pins 1 & 2 closed
75iMHz	pins 2 & 3 closed	pins 1 & 2 closed	pins 2 & 3 closed
100iMHz	pins 2 & 3 closed	pins 2 & 3 closed	pins 1 & 2 closed

CPU SPEED CONFIGURATION (80486DX4 ONLY)
Speed	JP18
2x	pins 2 & 3 closed
2.5x	pins 1 & 2 closed
3x	Open

CPU VOLTAGE CONFIGURATION
Voltage	P1	P2	P3
3.3v	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed
5v	pins 1 & 2 closed	pins 1 & 2 closed	pins 1 & 2 closed

VESA WAIT STATE CONFIGURATION
Wait states	JP13
1 wait state	Closed
2 wait states	Open

BUS SPEED CONFIGURATION
CPU speed	JP14
<= 33MHz	Open
> 33MHz	Closed

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