ABIT COMPUTER CORPORATION
VL-BUS 486 MAIN BOARD
|
Processor |
80486SX/80487SX/80486DX/80486DX2 |
|
Processor Speed |
25/33/40/50(internal)/50/66(internal)MHz |
|
Chip Set |
UNI |
|
Max. Onboard DRAM |
32MB |
|
Cache |
64/128/256KB |
|
BIOS |
AMI/Award |
|
Dimensions |
330mm x 218mm |
|
I/O Options |
32-bit VESA local bus slots (2) |
|
CONNECTIONS | |||
|
Purpose |
Location |
Purpose |
Location |
|
Power LED & keylock |
CN1 |
External battery |
CN6 |
|
Speaker |
CN3 |
Reset switch |
CN8 |
|
Turbo LED |
CN4 |
Power LED |
LED1 |
|
Turbo switch |
CN5 |
32-bit VESA local bus slots |
S1 & S2 |
|
USER CONFIGURABLE SETTINGS | |||
|
Function |
Jumper |
Position | |
|
» |
CMOS memory normal |
JP12 |
pins 1 & 2 closed |
|
CMOS memory clear |
JP12 |
pins 2 & 3 closed | |
|
» |
FAST A20 enabled |
JP17 |
pins 1 & 2 closed |
|
FAST A20 disabled |
JP17 |
pins 2 & 3 closed | |
|
» |
Monitor type select color |
JP18 |
Closed |
|
Monitor type select monochrome |
JP18 |
Open | |
|
» |
Factory configured - do not alter |
JP23 |
pins 1 & 2 closed |
|
» |
Factory configured - do not alter |
JP24 |
pins 1 & 2 closed |
|
» |
Factory configured - do not alter |
JP25 |
pins 1 & 2 closed |
|
» |
Factory configured - do not alter |
JP26 |
pins 2 & 3 closed |
|
» |
Power good signal detect from power supply |
JP27 |
pins 2 & 3 closed |
|
Power good signal detect from board |
JP27 |
pins 1 & 2 closed | |
|
» |
Factory configured - do not alter |
JP28 |
pins 2 & 3 closed |
|
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 write through U15 |
TAG write back U14,U15 |
|
64KB |
(4) 8K x 8 |
(4) 8K x 8 |
8K x 8 |
(2) 8K x 8 |
|
128KB |
(4) 32K x 8 |
NONE |
8K x 8 |
(2) 8K x 8 |
|
256KB |
(4) 32K x 8 |
(4) 32K x 8 |
32K x 8 |
(2) 32K x 8 |
|
CACHE JUMPER CONFIGURATION | |||||||
|
Size |
JP1 |
JP2 |
JP3 |
JP4 |
JP5 |
JP6 |
JP7 |
|
64KB write through |
N/A |
N/A |
1 & 2 |
1 & 2 |
2 & 3 |
1 & 2 |
1 & 2 |
|
64KB write back |
1 & 2 |
1 & 2 |
1 & 2 |
1 & 2 |
2 & 3 |
1 & 2 |
1 & 2 |
|
128KB write through |
N/A |
N/A |
2 & 3 |
1 & 2 |
1 & 2 |
1 & 2 |
2 & 3 |
|
128KB write back |
2 & 3 |
1 & 2 |
2 & 3 |
1 & 2 |
1 & 2 |
1 & 2 |
2 & 3 |
|
256KB write through |
N/A |
N/A |
2 & 3 |
2 & 3 |
2 & 3 |
2 & 3 |
2 & 3 |
|
256KB write back |
2 & 3 |
2 & 3 |
2 & 3 |
2 & 3 |
2 & 3 |
2 & 3 |
2 & 3 |
|
Note:Pins designated should be in the closed position. | |||||||
|
CPU SPEED CONFIGURATION | |||
|
Speed |
JP20 |
JP21 |
JP22 |
|
25MHz |
Closed |
Open |
Closed |
|
33MHz |
Open |
Closed |
Closed |
|
40MHz |
Closed |
Open |
Open |
|
50iMHz |
Closed |
Open |
Closed |
|
50MHz |
Open |
Closed |
Open |
|
66iMHz |
Open |
Closed |
Closed |
|
CPU TYPE CONFIGURATION | ||||
|
CPU Type |
JP13 |
JP14 |
JP15 |
JP16 |
|
80486SX PGA |
open |
pins 2 & 3 closed |
Open |
Closed |
|
80486 SX PQFP |
open |
pins 2 & 3 closed |
Open |
Open |
|
80487SX |
pins 2 & 3 closed |
pins 1 & 2 closed |
Closed |
N/A |
|
80486DX, DX2 |
pins 1 & 2 closed |
pins 1 & 2 closed |
Closed |
N/A |
|
VESA WAIT STATE/BUS SPEED CONFIGURATION | |||||
|
CPU speed |
Wait states |
JP8 |
JP9 |
JP10 |
JP11 |
|
< 33MHz |
0 wait states |
pins 1 & 2 |
pins 1 & 2 |
pins 1 & 2 |
pins 1 & 2 |
|
> 33MHz |
1 wait state |
pins 2 & 3 |
pins 2 & 3 |
pins 2 & 3 |
pins 2 & 3 |
|
Note: Pins designated should be in the closed position. | |||||