This document is for the full-sized (13.3" x 12.025") 80486DX-25, 80486DX-33 EISA
motherboard. The part number for this board is 09-00090-xx.
It's identifying features are: an LED between expansion slots #5 and #6; eight 32-bit
expansion slots; sixteen sockets for SIMMs (four banks of 4); a socket for a Weitek 4167
coprocessor.
The bus speed for this motherboard is fixed at 8MHz.
+=============================+
+ +
+ MOTHERBOARD SWITCH SETTINGS +
+ +
+ * = Default setting +
+=============================+
SW1
---
1 External cache not invalidated *Off
External cache invalidated On
2 On board Bios enabled *Off
On board Bios disabled On
3 64K external cache Off
128K or 256K external cache On
4 33MHz system Off
25MHz system On
5 Reserved *Off
6 Reserved *Off
7 CGA / EGA / VGA On
Monochrome Off
8 128K external cache On
64K or 256K external cache Off
SW2
---
1 Memory settings (see below)
2 Memory settings (see below)
3 Memory settings (see below)
4 Memory settings (see below)
5 Memory settings (see below)
6 Cache video Bios *Off
Don't cache video Bios On
7 Cache D00000-EFFFFF region *On
Don't cache D00000-EFFFFF Off
8 Reserved *Off
DIP switch settings for memory size
===================================
Memory Banks DIP Switch 2
---------------------------------------------------
MB 0 1 2 3 S1 S2 S3 S4 S5
---- ---- ---- ---- ---- ---- ---- ---- ---- ----
4MB 1MB ON ON ON ON ON
8MB 1MB 1MB OFF ON ON ON ON
12MB 1MB 1MB 1MB ON OFF ON ON ON
16MB 1MB 1MB 1MB 1MB OFF OFF ON ON OFF
16MB 4MB ON ON OFF ON OFF
20MB 1MB 4MB ON ON OFF OFF OFF
24MB 1MB 1MB 4MB ON OFF ON OFF OFF
28MB 1MB 1MB 1MB 4MB OFF ON ON OFF OFF
32MB 4MB 4MB OFF ON OFF ON OFF
36MB 1MB 4MB 4MB ON OFF OFF OFF OFF
40MB 1MB 1MB 4MB 4MB OFF OFF ON OFF OFF
48MB 4MB 4MB 4MB ON OFF OFF ON OFF
52MB 1MB 4MB 4MB 4MB OFF OFF OFF OFF OFF
64MB 4MB 4MB 4MB 4MB OFF OFF OFF ON OFF
In the table above, 1MB indicates that four 1Mx9 SIMMs are installed in the bank,
and 4MB indicates that four 4Mx9 SIMMs are installed in the bank. The above shows
all of the possible memory configurations.
When installing more than 16MB of memory, BIOS relocation must be disabled. Bios
relocation copies the video Bios (C0000-C7FFF) and the system ROM Bios (F0000-FFFFF) into
RAM. The motherboard adds 15MB to these addresses (F00000) to be able to differentiate
between the ROM and RAM. Enabling the relocation feature causes the memory above 16MB
to become non-contiguous and therefore inaccessible.
Micronics Computers has tested and verified the following memory brands:
Toshiba, Siemens, Mitsubishi, NEC
+=============================+
+ +
+ MOTHERBOARD JUMPER SETTINGS +
+ +
+=============================+
J2 Keyboard connector
Pin 1 - Keyboard clock
Pin 2 - Keyboard data
Pin 3 - no connector
Pin 4 - Ground
Pin 5 - +5 volts DC
J3 External 6-volt battery connector
Pin 1 - Battery Positive
Pin 2 - no connector
Pin 3 - Ground
Pin 4 - Ground
J15 External speaker
Pin 1 - Speaker
Pin 2 - no connector
Pin 3 - Ground
Pin 4 - +5 volts DC
J16 Keylock / Power LED
Pin 1 - Power LED signal
Pin 2 - no connector
Pin 3 - Ground
Pin 4 - Keyboard lock signal
Pin 5 - Ground
W3 External cache configuration
Pins 1-2 64K or 128K
Pins 2-3 256K
W4 External cache configuration
Pins 1-2 64K
Pins 2-3 128K or 256K
W5 Reset switch
Pin 1 - Signal
Pin 2 - Ground
W6 Turbo switch
Pin 1 - Signal
Pin 2 - Ground
W7 Turbo LED
Pin 1 - Signal
Pin 2 - Ground