LITTLE BOARD/486 Motherboard Settings and Configuration

Processor	80486SX/80487SX/80486DX
Processor Speed	20/33MHz
Chip Set	Ampro
Max. onboard DRAM	16MB
Cache	32KB optional (location unknown)
BIOS	Award
Dimensions	330mm x 218mm
I/O Options	Floppy drive interface, IDE interface, parallel port, SCSI connector, serial ports (2)
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
Power connector	J1	Parallel port	J6
Serial port (COM2)	J2	SCSI interface	J7
Serial port (COM1)	J3	Floppy drive interface	J8
Utility connector	J4	IDE interface	J11
Keyboard	J5	Power J1-1 to +12V BUS	W7

USER CONFIGURABLE SETTINGS
Function		Jumper/Switch	Position
»	SCSI controller enabled	W1	Closed
	SCSI controller disabled	W1	Open
»	Factory configured - do not alter	W3	N/A
»	SCSI controller select IRQ15	W5	Open
	SCSI controller select IRQ11	W5	Closed
»	SCSI termination power enabled	W6	Open
	SCSI termination power disabled	W6	Closed
»	Factory configured - do not alter	W10	Closed
»	Factory configured - do not alter	W11	pins 1 & 2 closed
»	Flash EPROM programming power enabled	W16	Open
	Flash EPROm programming power disabled	W16	Closed
»	Watchdog timer select I/O CHCK	W17	pins 1 & 2 closed
	Watchdog timer select reset	W17	pins 2 & 3 closed
	Watchdog timer disabled	W17	Open
»	Floppy drive interface enabled	W18	Open
	Floppy drive interface disabled	W18	Closed
»	Floppy precompensation (PCVAL) selection	W19	Open
	Floppy precompensation (PCVAL) none	W19	Closed
»	Floppy drive select IRQ6	W20 & W27	Closed
	Floppy drive select IRQ6 disabled	W20 & W27	Open
»	External cache enabled	W21	Open
	External cache disabled	W21	Closed
»	Factory configured - do not alter	W22	N/A
»	Power fail NMI enabled	W23	Open
	Power fail NMI disabled	W23	Closed
»	Parallel port interrrupt option select via setup	W24	Open
	Parallel port interrrupt option disabled	W24	Closed
Note: W18 may either be an option or is not user configurable.

DRAM CONFIGURATION
Size	Bank 0
1MB	(4) 256K x 9
4MB	(4) 1M x 9
16MB	(4) 4M x 9

CACHE CONFIGURATION
Cache	DRAM	U9	U10	Tag U12	Tag U13
32KB	4MB	(2) 8K x 8	(2) 8K x 8	(2) 8K x 8	NONE
32KB	16MB	(2) 8K x 8	(2) 8K x 8	(2) 8K x 8	(2) 8K x 8

EPROM CONFIGURATION (S0)
EPROM	W8	W9	W25
27C256	Open	pins 7 & 8, 10 & 11	pins 1 & 2
27C512	Open	pins 1 & 4, 7 & 8, 10 & 11	pins 1 & 2
27C010	Open	pins 1 & 4, 2 & 5, 6 & 9, 7 & 8	pins 1 & 2
27C020	Open	pins 1 & 4, 2 & 5, 6 & 9, 7 & 8, 11 & 12	pins 1 & 2
27C040	Open	pins 1 & 4, 2 & 3, 6 & 9, 7 & 8, 11 & 12	pins 1 & 2
27C080	Closed	pins 1 & 4, 2 & 3, 7 & 8, 11 & 12	pins 1 & 2
62256	Open	pins 4 & 7, 5 & 8, 10 & 11	pins 1 & 2 or 2 & 3
628128	Open	pins 1 & 2, 4 & 7, 5 & 8, 10 & 11	pins 1 & 2 or 2 & 3
uPD434000	Open	pins 1 & 2, 3 & 6, 4 & 7, 5 & 8, 11 & 12	pins 1 & 2 or 2 & 3
28F256	Open	pins 2 & 5, 6 & 9, 7 & 8	pins 1 & 2
28F512	Open	pins 1 & 4, 2 & 5, 6 & 9, 7 & 8	pins 1 & 2
28F010	Open	pins 1 & 4, 2 & 5, 6 & 9, 7 & 8	pins 1 & 2
28F020	Open	pins 1 & 4, 2 & 5, 6 & 9, 7 & 8, 11 & 12	pins 1 & 2
Note:Pins designated should be in the closed position.

EPROM/FLASH EPROM CONFIGURATION (S1 & S2)
EPROM	W12	W13	W14	W15
128KB	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed
256KB	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed	pins 2 & 3 closed

SCSI CONTROLLER CONFIGURATION
DMA	W2	W4
6	pins 1 & 2 closed	Open
0	pins 2 & 3 closed	Closed

UTILITY CONNECTOR (J4) PIN CONFIGURATION
Pin	Signal Name	Function
1	Speaker	Audio signal
2	Speaker	Ground
3	Ground	To one side of Reset button
4	Reset	To other side of Reset button
5	LED Cathode	Ground return
6	LED anode	Current source (+5v through 330 ohms)
7	Ground	Ground return
8	+12V power	Connected to P1 pin B9
9	-5V power	Connected to P1 pin B5
10	-12V power	Connected to P1 pin B7
11	Ground	Ground return
12	POWERGOOD	Power supply status

WATCHDOG TIMER CONFIGURATION
Setting	W17	W23
Disabled	Open	Open
IOCHCK (NMI)	Pins 1 & 2 closed	Open
Reset	pins 2 & 3 closed	N/A
Note:I/O channel check is the bus signal that triggers a non-maskable interrupt (NMI) Reset is a hard reset signal, the same as pressing the reset button.