MICRONICS MOTHERBOARD

80386SX-20/25 No cache (Baby size 09-00105-xx)

This document is for the baby-sized (8.5" x 13.3") 386SX-20 and 386SX-25 non-cached

motherboard. The part number for this board is 09-00105-xx.

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

expansion slots, and two 8-bit expansion slots; eight sockets for SIMMs (four banks of 2);

a socket for a 80387SX coprocessor.

The bus speed for this motherboard is fixed at 8MHz.

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+ MOTHERBOARD JUMPER SETTINGS +

+ +

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J1 External keyboard connector

Pin 1 - Keyboard clock

Pin 2 - Keyboard data

Pin 3 - no connector

Pin 4 - Ground

Pin 5 - +5 volts DC

J13 Monitor type

Not connected Color video card

Connected Monochrome video card

J14 Coprocessor configuration

Pins 1-2 Coprocessor installed

Not connected Coprocessor not installed

J15 80386 Pipeline configuration

Connected 80386 pipeline access

Not connected 80386 non-pipeline access

J24 External 6-volt battery connector

Pin 1 - Battery Positive

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Ground

J28 Turbo switch

Pin 1 - Signal

Pin 2 - Ground

J29 Turbo LED

Pin 1 - Signal

Pin 2 - Ground

J30 Reset switch

Pin 1 - Signal

Pin 2 - Ground

J31 External speaker

Pin 1 - Speaker

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - +5 volts DC

J32 Keylock / Power LED

Pin 1 - Power LED signal

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Keyboard lock signal

Pin 5 - Ground

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+ MEMORY CONFIGURATION +

+ +

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Listed below are the possible memory configurations

Size

in Bank Bank Bank Bank

MB 0 1 2 3

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

0.5 256K

1.0 256K 256K

1.5 256K 256K 256K

2.0 256K 256K 256K 256K

2.0 1MB

2.5 256K 1MB

3.0 256K 256K 1MB

4.0 1MB 1MB

4.5 256K 1MB

5.0 256K 1MB

6.0 1MB 1MB 1MB

8.0 1MB 1MB 1MB 1MB

8.0 4MB

8.5 256K 4MB

9.0 256K 256K 4MB

10.0 1MB 4MB

12.0 1MB 1MB 4MB

16.0 4MB 4MB

256K = Two 256Kx9 SIMMs in the bank

1MB = Two 1Mx9 SIMMs in the bank

4MB = Two 4Mx9 SIMMs in the bank