MICRONICS MOTHERBOARD

80486xx EISA (Baby size 09-00159-xx)

This document is for the baby-sized (13.3" x 8.5") 80486DX-33, DX2/66, DX-50, and

80486SX-25 EISA motherboard. The part number for this board is 09-00159-xx.

It's identifying features are: an LED between expansion slots #5 and #6; eight 32-bit

expansion slots; four sockets for SIMMs (four banks); a ZIF socket for

any DX, DX2, SX & Intel P24T Overdrive. The First 6 EISA slots support Bus Mastering Controllers.

The Standard EISA bus clock is fixed at 8.3MHz.

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+ MEMORY CHART +

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The following chart shows all of the possible memory configurations

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Memory Banks

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MB 0 1 2 3

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

4MB 1MB

8MB 1MB 1MB

12MB 1MB 1MB 1MB

16MB 1MB 1MB 1MB 1MB

16MB 4MB

20MB 1MB 4MB

24MB 1MB 1MB 4MB

32MB 4MB 4MB

36MB 1MB 4MB 4MB

40MB 1MB 1MB 4MB 4MB

48MB 4MB 4MB 4MB

52MB 1MB 4MB 4MB 4MB

64MB 4MB 4MB 4MB 4MB

In the table above 70ns or 60ns access time for DRAM /SIMMs is required,

1MB indicates that a 1Mx36 SIMM is installed in the bank, and 4MB indicates that

a 4Mx36 SIMMs are installed in the bank.

(1Mx36) = 4MB / 4096Kb of RAM and (4Mx36) = 16MB / 15360Kb of RAM

Micronics Computers has tested and verified the following memory brands:

Toshiba, Siemens, Mitsubishi, NEC & Micron

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+ MOTHERBOARD JUMPER SETTINGS +

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J23 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

J13 External speaker

Pin 1 - Speaker

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - +5 volts DC

J11 Keylock / Power LED

Pin 1 - Power LED signal

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Keyboard lock signal

Pin 5 - Ground

J9 Reset switch

Pin 1 - Signal

Pin 2 - Ground

J8 Turbo switch

Pin 1 - Signal

Pin 2 - Ground

J5 Turbo LED

Pin 1 - Signal

Pin 2 - Ground

J12 Video mode

Color - INSTALLED {Default}

MONO - OPEN

CPU SELECTION

i486SX ZIF Socket

PQFP Surface mounted CPU Selection JP1 JP2 JP3

None i486SX 1-2 3-4 2-3

None i486DX or I486DX2 2-3 1-2 1-2 & 3-4

i486SX NONE 1-2 3-4 2-3

i486SX i486DX OR DX/2 2-3 1-2 1-2 & 3-4

i486SX i487SX 1-2 1-2 1-2 & 3-4

i486SX i486SX Overdrive 1-2 2-3 1-2 & 3-4

For Earlier Revisions Ax J6

i486SX 2-3

i486DX 1-2 & 3-4

CPU Clock Speed J7 J10

33Mhz OFF ON i486DX/33, DX2/66, SX/33

25Mhz ON ON i486SX/25, DX2/50

50Mhz OFF OFF i486DX/50

Cache configuration

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Cache J15 J16 J17 J18 J19 J20 J21 J22

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64K 1-2 1-2 1-2 1-2 1-2 1-2 2-3 3-4

(8) 8Kx8 -20ns SRAM for U110-U116 & U118

(1) 64Kx1 -20ns SRAM for U103

(1) 32Kx8 -20NS SRAM for U104

128K 2-3 1-2 1-2 2-3 1-2 1-2 1-2 4-5

(4) 32Kx8 -20ns SRAM for U110-U112 & U118

(1) 64Kx1 -20ns SRAM for U103

(1) 32Kx8 -20NS SRAM for U104

256K 2-3 2-3 1-2 1-2 1-2 1-2 1-2 1-2

(8) 32Kx8 -20ns SRAM for U110-U116 & U118

(1) 64Kx1 -20ns SRAM for U103

(1) 16Kx4 -20NS SRAM for U101 & U102

512K 2-3 2-3 2-3 2-3 2-3 2-3 1-2 4-5

(4) 128Kx8 -20ns SRAM for U105-U108

(1) 64Kx1 -20ns SRAM for U103

(1) 32Kx8 -20ns SRAM for U104

U101 & U102 SRAM must be removed from a 256k cache configuration.