MICRONICS MOTHERBOARD

80486-25 ISA (Full size 09-00025-xx)

This document is for the full-sized (13.8" x 12.025") 486-25 ISA motherboard.

The part number for this board is 09-00025-xx.

It's identifying features are: an LED between expansion slots #5 and #6; eight 16-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.

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+ MOTHERBOARD SWITCH SETTINGS +

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+ * = Default setting +

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SW1

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1 Internal cache enabled *On

Internal cache disabled Off

2 Enable on-board Bios *Off

Enable external Bios On

3 Reserved *On

4 External cache enabled *On

External cache disabled Off

5 Bios relocation enabled On

Bios relocation disabled *Off

6 Reserved *Off

7 CGA / EGA / VGA *On

Monochrome Off

8 Reserved *Off

SW2

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1 Memory size (see below)

2 Memory size (see below)

3 Memory size (see below)

4 Memory size (see below)

5 Reserved *Off

6 D00000-EFFFFF cacheable *Off

D00000-EFFFFF non-cacheable On

7 64K or 256K external cache Off

128K external cache On

8 64K external cache Off

128K or 256K external cache On

DIP switch settings for memory size

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Memory Banks DIP Switch 2

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MB 0 1 2 3 S1 S2 S3 S4

---- ---- ---- ---- ---- ---- ---- ---- ----

1MB 256K ON ON ON ON

2MB 256K 256K OFF ON ON ON

3MB 256K 256K 256K ON OFF ON ON

4MB 256K 256K 256K 256K OFF OFF ON ON

4MB 1MB ON ON OFF ON

5MB 256K 1MB ON ON OFF OFF

6MB 256K 256K 1MB ON OFF ON OFF

7MB 256K 256K 256K 1MB OFF ON ON OFF

8MB 1MB 1MB OFF ON OFF ON

9MB 256K 1MB 1MB ON OFF OFF OFF

10MB 256K 256K 1MB 1MB OFF OFF ON OFF

12MB 1MB 1MB 1MB ON OFF OFF ON

13MB 256K 1MB 1MB 1MB OFF OFF OFF OFF

16MB 1MB 1MB 1MB 1MB OFF OFF OFF ON

In the table above, 256K indicates that four 256Kx9 SIMMs are installed in the bank,

and 1MB indicates that four 1Mx9 SIMMs are installed in the bank. The above shows

all of the possible memory configurations.

The maximum amount of memory supported by this board is 16MB.

Micronics Computers has tested and verified the following memory brands:

Toshiba, Siemens, Mitsubishi, NEC

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+ MOTHERBOARD JUMPER SETTINGS +

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J2 External 6-volt battery connector

Pin 1 - Battery Positive

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Ground

J22 External speaker

Pin 1 - Speaker

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - +5 volts DC

J23 Keylock / Power LED

Pin 1 - Power LED signal

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Keyboard lock signal

Pin 5 - Ground

W2 Reserved

Pins 2-3

W4 Reset switch

Pin 1 - Signal

Pin 2 - Ground

W5 Turbo LED

Pin 1 - Signal

Pin 2 - Ground

W6 Turbo switch

Pin 1 - Signal

Pin 2 - Ground

W8 External cache configuration

Pins 1-2 - 64K

Pins 2-3 - 128K or 256K

W9 External cache configuration

Pins 1-2 - 64K or 128K

Pins 2-3 - 256K