Processor	80486SX/80487SX/80486DX/ODP486SX/80486DX2
Processor Speed	33/66(internal)MHz
Chip Set	National/INTEL
Max. Onboard DRAM	256MB
SRAM Cache	64/128 (optional on CPU card only)
BIOS	AMI (located on CPU card)
Dimensions	307.34mm x 330.20mm
I/O Options	Floppy drive interface, IDE interface, parallel port, proprietary CPU card, serial port (2)
NPU Options	None

CONNECTIONS
Purpose	Location	Purpose	Location
8-bit ISA slot	J9	Serial port (COM2)	P7
Proprietary CPU card	J10	Speaker	P10
Keyboard interface	P1	Turbo Switch	P11
Floppy drive interface	P2	Power LED & keylock	P12
IDE interface	P3	IDE interface LED	P13
Auxiliary power connector	P4	Reset switch	P14
Parallel port	P5	Lockable reset switch	P15
Serial port (COM1)	P6

USER CONFIGURABLE SETTINGS
Function		Jumper	Position
»	IDE interface select IORDY at pin 21	JA-2	pins 2 & 4 closed
	IDE interface select IORDY at pin 27	JA-2	pins 4 & 6 closed
»	Watchdog strobe select 1.8MHz clock	JA-4	pins 5 & 6 closed
	Watchdog strobe select host address strobe	JA-4	pins 3 & 4 closed
	Watchdog strobe select signal watchdog	JA-4	pins 1 & 2 closed
»	IDE interface address latch enabled at IDE pin 28	JA-5	Closed
	IDE interface address select spindle sync at IDE pin 28	JA-5	Open
»	ISA bus select 0 wait state	JA-7	pins 1 & 3 open
	ISA bus select 1 wait state	JA-7	pins 1 & 3 closed
»	Posted memory write cycles enabled	JA-7	pins 2 & 4 closed
	Posted memory write cycles disabled	JA-7	pins 2 & 4 open
»	Factory configured - do not alter	JA-8 & JA-9	N/A
»	Keyboard buffer full interrupts from keyboard controller	JA-10	pins 2 & 3 closed
	Keyboard buffer full interrupts from 82351 at IRQ1	JA-10	pins 1 & 2 closed
»	Address enable active on slot 0 & slot 8 (J9)	JA-11	pins 1 & 2 closed
	Address enable active on slot 8 (J9) only	JA-11	pins 1 & 2 open
	. Factory configured - do not alter	JA-12	N/A
»	Factory configured - do not alter	JA-13	N/A
»	Memory speed select speed 1	JA-14	pins 1 & 3 closed
	Memory speed select speed 0	JA-14	pins 2 & 4 closed
»	CMOS memory normal operation	JA-15	pins 2 & 3 closed
	CMOS memory clear	JA-15	pins 1 & 2 closed
	Floppy drive select 2 drives	JA-17	Open
	Floppy drive select 3 drives	JA-17	pins 1 & 2, 3 & 4 closed
»	UART type 16550	JA18	pins 1 & 2 closed
	UART type 16540	JA18	pins 2 & 3 closed
»	IDE interface select National chipset	JA-19	pins 1 & 2 closed
	IDE interface Intel chipset	JA-19	pins 2 & 3 closed
»	Floppy drive select National chipsey	JA--20	pins 1 & 2 closed
	Floppy drive select Intel chipset	JA-20	pins 2 & 3 closed
»	Keylock disabled	JA-21	pins 2 & 3 closed
	Keylock enabled	JA-21	pins 1 & 2 closed
Note:SW1 & SW2 are software dependent.

DRAM CONFIGURATION
Size	Bank0	Bank1	Bank2	Bank3	Bank4	Bank5	Bank6	Bank7
1MB	256K	NONE	NONE	NONE	NONE	NONE	NONE	NONE
2MB	256K	256K	NONE	NONE	NONE	NONE	NONE	NONE
2MB	512K	NONE	NONE	NONE	NONE	NONE	NONE	NONE
3MB	256K	256K	256K	NONE	NONE	NONE	NONE	NONE
4MB	256K	256K	256K	256K	NONE	NONE	NONE	NONE
4MB	512K	512K	NONE	NONE	NONE	NONE	NONE	NONE
4MB	1M	NONE	NONE	NONE	NONE	NONE	NONE	NONE
5MB	256K	256K	256K	256K	256K	NONE	NONE	NONE
6MB	256K	256K	256K	256K	256K	256K	NONE	NONE
6MB	256K	256K	256K	256K	512K	NONE	NONE	NONE
6MB	512K	512K	512K	NONE	NONE	NONE	NONE	NONE
7MB	256K	256K	256K	256K	256K	256K	256K	NONE
8MB	256K	256K	256K	256K	256K	256K	256K	256K
8MB	256K	256K	256K	256K	512K	512K	NONE	NONE
8MB	256K	256K	256K	256K	1M	NONE	NONE	NONE
8MB	512K	512K	512K	512K	NONE	NONE	NONE	NONE
8MB	1M	1M	NONE	NONE	NONE	NONE	NONE	NONE
8MB	2M	NONE	NONE	NONE	NONE	NONE	NONE	NONE
9MB	512K	512K	512K	512K	256K	NONE	NONE	NONE
10MB	512K	512K	512K	512K	256K	256K	NONE	NONE
10MB	512K	512K	512K	512K	512K	NONE	NONE	NONE
11MB	512K	512K	512K	512K	256K	256K	256K	NONE
12MB	512K	512K	512K	512K	256K	256K	256K	256K
12MB	512K	512K	512K	512K	512K	512K	NONE	NONE
12MB	512K	512K	512K	512K	1M	NONE	NONE	NONE
12MB	1M	1M	1M	NONE	NONE	NONE	NONE	NONE
14MB	512K	512K	512K	512K	512K	512K	512K	NONE
16MB	512K	512K	512K	512K	512K	512K	512K	512K
16MB	512K	512K	512K	512K	1M	1M	NONE	NONE
16MB	512K	512K	512K	512K	2M	NONE	NONE	NONE
16MB	1M	1M	1M	1M	NONE	NONE	NONE	NONE
16MB	2M	2M	NONE	NONE	NONE	NONE	NONE	NONE
16MB	4M	NONE	NONE	NONE	NONE	NONE	NONE	NONE
17MB	1M	1M	1M	1M	256K	NONE	NONE	NONE
18MB	1M	1M	1M	1M	256K	256K	NONE	NONE
18MB	1M	1M	1M	1M	512K	NONE	NONE	NONE
19MB	1M	1M	1M	1M	256K	256K	256K	NONE
20MB	1M	1M	1M	1M	256K	256K	256K	256K
20MB	1M	1M	1M	1M	512K	512K	NONE	NONE
20MB	1M	1M	1M	1M	1M	NONE	NONE	NONE
22MB	1M	1M	1M	1M	512K	512K	512K	NONE
24MB	1M	1M	1M	1M	512K	512K	512K	512K
24MB	1M	1M	1M	1M	1M	1M	NONE	NONE
DRAM CONFIGURATION (CONTINUED) Size Bank0 Bank1 Bank2 Bank3 Bank4 Bank5 Bank6 Bank7 24MB 1M 1M 1M 1M 2M NONE NONE NONE 24MB 2M 2M 2M NONE NONE NONE NONE NONE 28MB 1M 1M 1M 1M 1M 1M 1M NONE 32MB 1M 1M 1M 1M 1M 1M 1M 1M 32MB 1M 1M 1M 1M 2M 2M NONE NONE 32MB 1M 1M 1M 1M 4M NONE NONE NONE 32MB 4M 4M NONE NONE NONE NONE NONE NONE 32MB 8M NONE NONE NONE NONE NONE NONE NONE 32MB 2M 2M 2M 2M NONE NONE NONE NONE 33MB 2M 2M 2M 2M 256K NONE NONE NONE 34MB 2M 2M 2M 2M 256K 256K NONE NONE 34MB 2M 2M 2M 2M 512K NONE NONE NONE 35MB 2M 2M 2M 2M 256K 256K 256K NONE 36MB 2M 2M 2M 2M 256K 256K 256K 256K 36MB 2M 2M 2M 2M 512K 512K NONE NONE 36MB 2M 2M 2M 2M 1M NONE NONE NONE 38MB 2M 2M 2M 2M 512K 512K 512K NONE 40MB 2M 2M 2M 2M 512K 512K 512K 512K 40MB 2M 2M 2M 2M 1M 1M NONE NONE 40MB 2M 2M 2M 2M 2M NONE NONE NONE 44MB 2M 2M 2M 2M 1M 1M 1M NONE 48MB 2M 2M 2M 2M 1M 1M 1M 1M 48MB 2M 2M 2M 2M 2M 2M NONE NONE 48MB 2M 2M 2M 2M 4M NONE NONE NONE 48MB 4M 4M 4M NONE NONE NONE NONE NONE 56MB 2M 2M 2M 2M 2M 2M 2M NONE 64MB 2M 2M 2M 2M 2M 2M 2M 2M 64MB 2M 2M 2M 2M 4M 4M NONE NONE 64MB 2M 2M 2M 2M 8M NONE NONE NONE 64MB 4M 4M 4M 4M NONE NONE NONE NONE 64MB 8M 8M NONE NONE NONE NONE NONE NONE 65MB 4M 4M 4M 4M 256K NONE NONE NONE 66MB 4M 4M 4M 4M 256K 256K NONE NONE 66MB 4M 4M 4M 4M 512K NONE NONE NONE 67MB 4M 4M 4M 4M 256K 256K 256K NONE 68MB 4M 4M 4M 4M 256K 256K 256K 256K 68MB 4M 4M 4M 4M 512K 512K NONE NONE 68MB 4M 4M 4M 4M 1M NONE NONE NONE 70MB 4M 4M 4M 4M 512K 512K 512K NONE 72MB 4M 4M 4M 4M 512K 512K 512K 512K 72MB 4M 4M 4M 4M 1M 1M NONE NONE 72MB 4M 4M 4M 4M 2M NONE NONE NONE DRAM CONFIGURATION (CONTINUED) Size Bank0 Bank1 Bank2 Bank3 Bank4 Bank5 Bank6 Bank7 80MB 4M 4M 4M 4M 2M 2M NONE NONE 80MB 4M 4M 4M 4M 4M NONE NONE NONE 88MB 4M 4M 4M 4M 2M 2M 2M NONE 96MB 4M 4M 4M 4M 4M 4M NONE NONE 96MB 4M 4M 4M 4M 8M NONE NONE NONE 96MB 4M 4M 4M 4M 2M 2M 2M 2M 96MB 8M 8M 8M NONE NONE NONE NONE NONE 128MB 8M 8M 8M 8M NONE NONE NONE NONE 128MB 4M 4M 4M 4M 8M 8M NONE NONE 129MB 8M 8M 8M 8M 256K NONE NONE NONE 130MB 8M 8M 8M 8M 256K 256K NONE NONE 130MB 8M 8M 8M 8M 512K NONE NONE NONE 131MB 8M 8M 8M 8M 256K 256K 256K NONE 132MB 8M 8M 8M 8M 256K 256K 256K 256K 132MB 8M 8M 8M 8M 512K 512K NONE NONE 132MB 8M 8M 8M 8M 1M NONE NONE NONE 134MB 8M 8M 8M 8M 512K 512K 512K NONE 136MB 8M 8M 8M 8M 512K 512K 512K 512K 136MB 8M 8M 8M 8M 1M 1M NONE NONE 136MB 8M 8M 8M 8M 2M NONE NONE NONE 140MB 8M 8M 8M 8M 1M 1M 1M NONE 144MB 8M 8M 8M 8M 1M 1M 1M 1M 144MB 8M 8M 8M 8M 2M 2M NONE NONE 144MB 8M 8M 8M 8M 4M NONE NONE NONE 152MB 8M 8M 8M 8M 2M 2M 2M NONE 160MB 8M 8M 8M 8M 2M 2M 2M 2M 160MB 8M 8M 8M 8M 4M 4M NONE NONE 160MB 8M 8M 8M 8M 8M NONE NONE NONE 176MB 8M 8M 8M 8M 4M 4M 4M NONE 192MB 8M 8M 8M 8M 4M 4M 4M 4M 192MB 8M 8M 8M 8M 8M 8M NONE NONE 224MB 8M 8M 8M 8M 8M 8M 8M NONE 256MB 8M 8M 8M 8M 8M 8M 8M 8M Note: The 512K x 36, 2M x 36, and 8M x 36 SIMMs are double-sided SIMMs. FLOPPY DRIVE 0 CONFIGURATION A: JA-1/pins 2 & 4 3.5" Closed 5.25" Open FLOPPY DRIVE 1 CONFIGURATION B: JA-1/pins 1 & 3 3.5" Closed 5.25" Open FLOPPY DRIVE POWER CONFIGURATION Drive Type RP3 Normal 3.5" 150 W Low power 3.5" 1K W IDE INTERFACE I/O READY SIGNAL CONFIGURATION IORDY JA-2/pins 2, 4, & 6 At pin 21 of IDE interface pins 2 & 4 closed At pin 27 of IDE interface pins 4 & 6 closed Note:If the hard drive has the IORDY signal at at both pins then either configuration will work. IDE INTERFACE DMA CONFIGURATION DMA JA-2/pins 1 & 2 JA-2/pins 3 & 5 JA-6 & JA-16 DMA6 Closed Closed pins 1 & 2 closed Disabled Open Open pins 2 & 3 closed Note:If the drive supports DMA then the IORDY signal must be at pin 27 of the IDE interface. WATCHDOG TIMER CONFIGURATION Timeout Minimum Timeout Typical Timeout Maximum JA-3 50ms 150ms 250ms pins 1 & 2 closed 250ms 600ms 1000ms Open 400ms 1200ms 2000ms pins 2 & 3 closed CONNECTIONS Purpose Location CPU cooling fan power +12VDC P1 Optional secondary cache module (64K or 128K) U7 Note:All DRAM banks must be populated on the motherboard before any cache modules can be installed. USER CONFIGURABLE SETTINGS Function Jumper Position » Flash memory normal operation at address A16 JA-1 pins 2 & 3 closed   Flash memory inverted operation at address A16 JA-1 pins 1 & 2 open » Flash BIOS write protect enabled JA-2 pins 1 & 3, 2 & 4 closed   Flash BIOS write protect disabled JA-2 pins 1 & 3, 2 & 4 open CPU TYPE CONFIGURATION Type Speed JA-3 JA-4 80486SX 33MHz pins 1 & 2 closed pins 2 & 4 closed 80486DX/DX2 33/66i MHz pins 1 & 2 closed pins 1 & 2, 3 & 4 closed ODPR486DX 33MHz pins 1 & 2 closed pins 1 & 2, 3 & 4 closed ODP486DX 33MHz pins 2 & 3 closed pins 1 & 2, 3 & 4 closed Note:ODPR486DX is pin compatible with the 80486DX/80486DX2 processors.