MICRONICS MOTHERBOARD

80486-33 (Baby size 09-00081-xx and 09-00135-xx)

This document is for the baby-sized (13.3" x 8.5") Baby Gemini 486-33 motherboard.

The part number for this board is 09-00081-xx, and also 09-00135-xx.

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

expansion slots; eight sockets for SIMMs (two banks of 4); a socket for a Weitek 4167

coprocessor; one proprietary 32-bit slot which accommodates the M810 (a memory

expansion card with eight sockets for SIMMs).

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 Reserved *On

2 Reserved *Off

3 Reserved *Off

4 Reserved *Off

5 Reserved *Off

6 Reserved *Off

7 Reserved *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 Memory size (see below)

6 Reserved *On

7 Reserved *Off

8 64K external cache Off

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 S5

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

1MB 256K ON ON ON ON ON

2MB 256K 256K OFF ON ON ON ON

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

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

4MB 1MB ON ON OFF ON ON

5MB 256K 1MB ON ON OFF OFF ON

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

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

8MB 1MB 1MB OFF ON OFF ON ON

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

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

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

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

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

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

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.

Please note that Bank 0 and Bank 1 are on the motherboard. Banks 2 and 3 are found on

the M810. Each bank consists of four SIMMs, and all four sockets within a bank must

be filled.

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

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+ MOTHERBOARD JUMPER SETTINGS +

+ +

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J11 External 6-volt battery connector

Pin 1 - Battery Positive

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Ground

J23 External speaker

Pin 1 - Speaker

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - +5 volts DC

J24 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

Not installed - 64K

Installed - 256K

W4 External cache configuration

Not installed - 64K

Installed - 256K

W5 Turbo LED

Pin 1 - Signal

Pin 2 - Ground

W6 Reset switch

Pin 1 - Signal

Pin 2 - Ground

W7 Turbo switch

Pin 1 - Signal

Pin 2 - Ground

W15 External cache configuration

Pins 1-2 - 256K

Pins 2-3 - 64K