AT4 Motherboard Settings and Configuration

Processor	80486SX/80486DX/P23T
Processor Speed	16/25/33/50MHz
Chip Set	Unidentified
Video Chip Set	None
Maximum Onboard Memory	32MB
Maximum Video Memory	None
Cache	32/64/128/256/512/1024KB
BIOS	AMI
Dimensions	330mm x 218mm
I/O Options	None
NPU Options	4167

CONNECTIONS
Purpose	Location	Purpose	Location
Speaker	CN1	Turbo switch	JP1
Power LED & keylock	CN2	Turbo LED	JP2
External battery	CN3	Reset switch	SW1

USER CONFIGURABLE SETTINGS
Function		Label	Position
»	CMOS memory normal operation	JP5	Pins 1 & 2 closed
	CMOS memory clear	JP5	Pins 2 & 3 closed
	Monitor type select CGA/EGA/VGA	JP7	Closed
	Monitor type select monochrome	JP7	Open
»	Factory configured - do not alter	JP8	Open
»	Factory configured - do not alter	JP9	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
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	TAG0
32KB	(4) 8K x 8	None	(1) 8K x 8	(2) 16K x 4
64KB	(4) 8K x 8	(4) 8K x 8	(1) 8K x 8	(2) 16K x 4
128KB	(4) 32K x 8	None	(1) 8K x 8	(2) 16K x 4
256KB	(4) 32K x 8	(4) 32K x 8	(1) 32K x 8	(2) 16K x 4
512KB	(4) 128K x 8	None	(1) 32K x 8	(2) 64K x 4
1MB	(4) 128K x 8	(4) 128K x 8	(1) 128K x 8	(2) 64K x 4
Note: Use either TAG chip or TAG0 chips. All three sockets can’t be installed at the same time.

CACHE JUMPER CONFIGURATION
Size	JP3	JP4	JPX4	JPX5
32KB	N/A	Open	Pins 1 - 8 installed	Pins 1 - 8 installed
64KB	N/A	Open	Pins 9 - 16 installed	Pins 3 - 10 installed
128KB	N/A	Closed	Pins 1 - 8 installed	Pins 5 - 12 installed
256KB	N/A	Closed	Pins 9 - 16 installed	Pins 7 - 14 installed
512KB	N/A	Closed	Pins 1 - 8 installed	Pins 9 - 16 installed
1MB	Closed	Closed	Pins 9 - 16 installed	Pins 9 - 16 installed

CPU TYPE SELECTION
Type	JP6	JPX3
80486SX	Closed	Not installed
80486DX	Open	Installed
P23T	Open	Installed