SCI SYSTEMS, INC.
SCI 486SX/DX SYSTEM BOARD
| 
 Processor  | 
 80486SX/80486DX  | 
| 
 Processor Speed  | 
 25/33MHz  | 
| 
 Chip Set  | 
 OPTI  | 
| 
 Max. Onboard DRAM  | 
 64MB  | 
| 
 Cache  | 
 64/256KB  | 
| 
 BIOS  | 
 Unidentified  | 
| 
 Dimensions  | 
 330mm x 218mm  | 
| 
 I/O Options  | 
 Floppy drive interface, IDE interface, parallel port, PS/2 mouse port, serial ports (2), VGA port  | 
| 
 NPU Options  | 
 None  | 
| 
 CONNECTIONS  | |||
| 
 Purpose  | 
 Location  | 
 Purpose  | 
 Location  | 
| 
 PS/2 mouse port  | 
 J1  | 
 IDE interface LED  | 
 J23  | 
| 
 IDE interface  | 
 J5  | 
 Reset switch  | 
 J24  | 
| 
 Floppy drive interface  | 
 J6  | 
 Speaker  | 
 J25  | 
| 
 Parallel port  | 
 J8  | 
 Power LED & keylock  | 
 J26  | 
| 
 Serial port 2  | 
 J9  | 
 VGA port  | 
 J27  | 
| 
 Serial port 1  | 
 J10  | ||
| 
 USER CONFIGURABLE SETTINGS  | |||
| 
 Function  | 
 Jumper/Switch  | 
 Position  | |
| 
 »  | 
 Monitor type select color  | 
 W1  | 
 pins 1 & 2 closed  | 
| 
 Monitor type select monochrome  | 
 W1  | 
 pins 2 & 3 closed  | |
| 
 »  | 
 CMOS memory normal operation  | 
 W2  | 
 pins 1 & 2 closed  | 
| 
 CMOS memory clear  | 
 W2  | 
 pins 2 & 3 closed  | |
| 
 »  | 
 SYSCLK enabled  | 
 W3  | 
 pins 2 & 3 closed  | 
| 
 SYSCLK/2 enabled  | 
 W3  | 
 pins 1 & 2 closed  | |
| 
 »  | 
 On board VGA enabled  | 
 W10  | 
 pins 1 & 2 closed  | 
| 
 On board VGA disabled  | 
 W10  | 
 pins 2 & 3 closed  | |
| 
 »  | 
 Video horizontal scan rate select 31.5 kHz  | 
 SW1/5  | 
 On  | 
| 
 Video horizontal scan rate select 40kHz  | 
 SW1/5  | 
 Off  | |
| 
 »  | 
 Video memory select 512KB  | 
 SW1/6  | 
 On  | 
| 
 Video memory select 1MB  | 
 SW1/6  | 
 Off  | |
| 
 DRAM CONFIGURATION  | ||||
| 
 Size  | 
 Bank 0  | 
 Bank 1  | 
 Bank 2  | 
 Bank 3  | 
| 
 1MB  | 
 (1) 256K x 36  | 
 NONE  | 
 NONE  | 
 NONE  | 
| 
 2MB  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 NONE  | 
 NONE  | 
| 
 4MB  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
 NONE  | 
| 
 5MB  | 
 (1) 256K x 36  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
| 
 6MB  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 8MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
| 
 9MB  | 
 (1) 256K x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 10MB  | 
 (1) 256K x 36  | 
 (1) 256K x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 12MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 13MB  | 
 (1) 256K x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 16MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 16MB  | 
 (1) 4M x 36  | 
 NONE  | 
 NONE  | 
 NONE  | 
| 
 20MB  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 NONE  | 
 NONE  | 
| 
 20MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
 NONE  | 
| 
 24MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 NONE  | 
| 
 24MB  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 24MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 28MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
| 
 28MB  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 28MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 32MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 NONE  | 
 NONE  | 
| 
 36MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 36MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 36MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 NONE  | 
| 
 40MB  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
| 
 40MB  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
| 
 40MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
| 
 40MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 1M x 36  | 
| 
 DRAM CONFIGURATION (CON’T)  | ||||
| 
 Size  | 
 Bank 0  | 
 Bank 1  | 
 Bank 2  | 
 Bank 3  | 
| 
 48MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 NONE  | 
| 
 52MB  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
| 
 52MB  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
| 
 52MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 1M x 36  | 
| 
 64MB  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
 (1) 4M x 36  | 
| 
 CACHE CONFIGURATION  | |||
| 
 Size  | 
 Bank 0  | 
 Bank 1  | 
 TAG  | 
| 
 64KB  | 
 (4) 8K x 8  | 
 (4) 8K x 8  | 
 (2) 16K x 4  | 
| 
 256KB  | 
 (4) 32K x 8  | 
 (4) 32K x 8  | 
 (2) 16K x 4  | 
| 
 CACHE JUMPER CONFIGURATION  | ||||
| 
 Size  | 
 W4  | 
 W5  | 
 W9  | 
 W11  | 
| 
 64KB  | 
 pins 2 & 3 closed  | 
 pins 2 & 3 closed  | 
 pins 2 & 3 closed  | 
 pins 2 & 3 closed  | 
| 
 256KB  | 
 pins 1 & 2 closed  | 
 pins 1 & 2 closed  | 
 pins 1 & 2 closed  | 
 pins 2 & 3 closed  | 
| 
 CPU TYPE CONFIGURATION  | |||
| 
 Type  | 
 W6  | 
 W7  | 
 W8  | 
| 
 486SX  | 
 pins 2 & 3 closed  | 
 pins 2 & 3 closed  | 
 N/A  | 
| 
 487SX  | 
 pins 1 & 2 closed  | 
 pins 1 & 2 closed  | 
 pins 1 & 2 closed  | 
| 
 486DX  | 
 pins 1 & 2 closed  | 
 pins 1 & 2 closed  | 
 pins 2 & 3 closed  | 
| 
 VIDEO CONFIGURATION (800 X 600)  | |||
| 
 Refresh rate  | 
 SW1/1  | 
 SW1/2  | |
| » | 
 60Hz  | 
 Off  | 
 On  | 
| 
 56Hz  | 
 Off  | 
 Off  | |
| 
 56Hz  | 
 On  | 
 On  | |
| 
 72Hz  | 
 On  | 
 Off  | |
| 
 VIDEO CONFIGURATION (1024 X 768)  | |||
| 
 Refresh rate  | 
 SW1/3  | 
 SW1/4  | |
| » | 
 Interlaced  | 
 Off  | 
 Off  | 
| 
 60Hz  | 
 Off  | 
 On  | |
| 
 70Hz  | 
 On  | 
 Off  | |
| 
 72Hz  | 
 On  | 
 On  | |
| 
 VIDEO MEMORY CONFIGURATION  | ||
| 
 Size  | 
 Bank 0  | 
 Bank 1  | 
| 
 512KB  | 
 (4) 256K x 4  | 
 NONE  | 
| 
 1MB  | 
 (4) 256K x 4  | 
 (4) 256K x 4  | 
| 
 Note: Bank 0 is factory installed and is not configurable.  | ||