PB450, LEGEND-CD 486SX Motherboard Settings and Configuration

Processor	80486SX/SL80486SX/80486DX/SL80486DX/80486DX2/SL80486DX2/80486DX4/P24T
Processor Speed	25/33/50(internal)/66(internal)/75(internal)/100(internal)MHz
Chip Set	OPTI
Video Chip Set	Cirrus Logic
Maximum Onboard Memory	64MB
Maximum Video Memory	2MB
Cache	128/512KB
BIOS	Unidentified
Dimensions	254mm x 218mm
I/O Options	Floppy drive interface, IDE interfaces (2), parallel port, PS/2 mouse port, serial ports (2), VESA feature connector, VGA port, riser slot
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
PS/2 mouse port	J2	IDE interface 1	J24
VGA port	J3	External battery	J30
Parallel port	J5	Front panel connector	J34
Serial port 1	J6	Power LED & keylock	J35
VESA feature connector	J14	Speaker	J36
Floppy drive interface	J21	Chassis fan power	J38
Serial port 2/modem connector	J22	Riser slot	SL1
IDE interface 2	J23

USER CONFIGURABLE SETTINGS
Function		Label	Position
»	Monitor type select color	J8	Closed
	Monitor type select monochrome	J8	Open
»	Video IRQ9 disabled	J9	Open
	Video IRQ9 enabled	J9	Closed
»	Factory configured - do not alter	J10	Unidentified
»	Factory configured - do not alter	J11	Unidentified
»	Flash BIOS normal operation	J17	Pins 2 & 3 closed
	Flash BIOS boot block enabled	J17	Pins 1 & 2 closed
»	DRAM parity disabled	J18	Pins 2 & 3 closed
	DRAM parity enabled	J18	Pins 1 & 2 closed
»	On board video enabled	J19	Pins 2 & 3 closed
	On board video disabled	J19	Pins 1 & 2 closed
»	On board I/O enabled	J20	Pins 2 & 3 closed
	On board I/O disabled	J20	Pins 1 & 2 closed
	Battery type select internal	J30	Pins 3 & 4 closed
	Battery type select external	J30	Closed
»	LDEV# bypass enabled	J33	Closed
	LDEV# bypass disabled (PCI card present)	J33	Open
	Speaker type select internal	J36	Pins 3 & 4 closed
	Speaker type select external	J36	Closed
»	On board memory enabled	J37	Open
	On board memory disabled	J37	Closed

DRAM CONFIGURATION
Size	Bank 0	Bank 1	Bank 2
4MB	4MB	None	None
5MB	4MB	(1) 256K x 36	None
6MB	4MB	(1) 256K x 36	(1) 256K x 36
6MB	4MB	(1) 512K x 36	None
8MB	4MB	(1) 512K x 36	(1) 512K x 36
8MB	4MB	(1) 1M x 36	None
12MB	4MB	(1) 1M x 36	(1) 1M x 36
12MB	4MB	(1) 2M x 36	None
16MB	4MB	(1) 2M x 36	(1) 1M x 36
20MB	4MB	(1) 2M x 36	(1) 2M x 36
20MB	4MB	(1) 4M x 36	None
24MB	4MB	(1) 4M x 36	(1) 1M x 36
24MB	4MB	(1) 1M x 36	(1) 4M x 36
28MB	4MB	(1) 2M x 36	(1) 4M x 36
36MB	4MB	(1) 4M x 36	(1) 4M x 36
36MB	4MB	(1) 8M x 36	None
40MB	4MB	(1) 8M x 36	(1) 1M x 36
52MB	4MB	(1) 8M x 36	(1) 4M x 36
64MB	4MB	(1) 8M x 36	(1) 8M x 36
Note: If 64MB is installed, J37 must be closed.

CACHE CONFIGURATION
Size	Bank 0	TAG0	TAG1
128KB	(4) 32K x 8	(1) 32K x 8	(1) 64K x 1
512KB	(4) 128K x 8	(1) 32K x 8	(1) 64K x 1

CACHE JUMPER CONFIGURATION
Size	J26
128KB	Open
512KB	Pins 1 & 2, 3 & 4 closed

VIDEO MEMORY CONFIGURATION
Size	Bank 0
2MB	(2) 256K x 16

CPU SPEED SELECTION
Speed	J25
25MHz	Pins 1 & 2 closed
33MHz	Pins 2 & 3 closed
50iMHz	Pins 1 & 2 closed
66iMHz	Pins 2 & 3 closed
75iMHz	Pins 1 & 2 closed
100iMHz	Pins 2 & 3 closed

CPU TYPE SELECTION
Type	J28	J31
80486SX	Pins 2 & 3 closed	Pins 5 & 6 closed
SL80486SX	Pins 1 & 2 closed	Pins 1 & 2, 3 & 4 closed
80486DX	Pins 2 & 3 closed	Pins 1 & 2, 3 & 4 closed
SL80486DX	Pins 1 & 2 closed	Pins 1 & 2, 3 & 4 closed
80486DX2	Pins 2 & 3 closed	Pins 1 & 2, 3 & 4 closed
SL80486DX2	Pins 1 & 2 closed	Pins 1 & 2, 3 & 4 closed
80486DX4	Pins 2 & 3 closed	Pins 1 & 2, 3 & 4 closed
P24T	Pins 1 & 2 closed	Pins 1 & 2, 3 & 4 closed

CPU MULTIPLIER SELECTION (80486DX4 ONLY)
Multiplier	J29
2x	Pins 2 & 3 closed
3x	Open

CPU VOLTAGE SELECTION
Voltage	J32
3.3v	Pins 1 & 3, 2 & 4 closed
5v	Pins 3 & 5, 4 & 5 closed

DMA CHANNEL SELECTION
Channel		J15	J16
»	1	Pins 1 & 2 closed	Pins 1 & 2 closed
	3	Pins 2 & 3 closed	Pins 2 & 3 closed