Deico 486-DX VESA Local bus mainboard
Deico 486-DX VESA Local bus mainboard only supports 386DX, 486DLC, 486SX, 487SX and 486DX processors. The CPU is into one of three sockets and selectable by
jumper JP27.
Memory
Deico 486-DX VESA mainboard has four memory connectors 2x 72 pin each.
Cache memory has two bankch, each selectable to 64 kB or 128 kB or 256 kB. Each cache memory bank contains four
narrow DIL28 memory integrated circuits. Beside both cache memory banks, the mainboard has a TAG RAM of 16 kB.
BIOS
The mainboard has 486DX ISA AMI BIOS with support of floppy discs, IDE hard disc, printer port, two serial ports, keyboard and mouse.
BIOS is stored in one EPROM 27C512. Here are images of this BIOS: (ZIP file contains EPROM images in HEX-Intel/Motorola/Tektronix and Binary formats) .
Expansion bus
The Deico 486-DX VESA mainboard has 16-bit expansion bus with six expansion-connectors and two shared VESA Local
bus expansion-connectors
|
| Producer: |
Deico |
| Year: |
1992 |
| Origin: |
Taiwan |
| Chips: |
Symphony SL62C361 & SL62C362 |
| RAM: |
256 kB up to 4 MB, modules 2x 72 pins |
| Cache: |
64 kB / 128 kB / 256 kB selectable by jumper |
| Support: |
AMI BIOS 486DX 1992 |
| Connectors: |
1x parallel port, 2x serial, kbd & mouse, floppy disc, IDE hard disc |
| Interface: |
6x ISA and 2x VESA shared |
| OS support: |
MS WIN 3.1 |
| Size: |
219 x 330 mm |
| DOCUMENTATION: |
none |
Jumpers
| JP1 |
System |
1-2 normal
2-3 reset CMOS |
| JP2 |
System |
1-2 normal
2-3 emergency |
| JP3 |
Input/Output |
1-2 enable
2-3 disable |
| JP4 |
LPT IRQ |
1-2 LPT1 = IRQ7
2-3 LPT1 = IRQ5
3-4 no IRQ |
| JP5 |
COM1/3 IRQ |
1-2 COM1/3 = IRQ4
2-3 COM1/3 = IRQ5
3-4 no IRQ |
| JP6 |
COM2/4 IRQ |
1-2 COM2/4 = IRQ3
2-3 COM2/4 = IRQ9
3-4 no IRQ |
| JP8 |
Video |
1-2 color
2-3 mono |
| JP9 |
Mouse |
1-2 IRQ12
2-3 disable |
| JP11 |
VL-BUS wait states |
1-2 0 wait state
2-3 1 wait state |
| JP12, JP13, JP14 |
CACHE Bank 2 selection |
1-2 64 kB
2-3 128 kB
3-4 256 kB |
| JP16, JP17, JP18, JP19, JP20 |
CACHE Bank 2 selection |
1-2 64 kB
2-3 128 kB
3-4 256 kB |
| JP21 |
CPU freq. |
1-2 normal
2-3 not 50 MHz |
| JP22, JP23, JP30 |
CPU mfg. |
1-2 other
2-3 Cyrix |
| JP27 |
CPU selection |
1-2 486DX
3-4 487SX
5-6 486SX
7-8 386DX/486DLC |
| JP28, JP29 |
CACHE Bank 1 selection |
1-2 486DX, 486SX or 386DX, 128KB
2-3 386DX, 64KB/128KB |
| JP31 |
CPU freq. |
1-2 50 MHz
2-3 not 50 MHz |
| JP32 |
CPU freq. |
1-2 not 50 MHz
2-3 50 MHz |
|
