MICRONICS MOTHERBOARD

80486xx JX30 VL-Bus (Baby size 09-00183)

This document is for the baby-sized (13.3" x 8.5") JX30 VL-Bus motherboard.

The part number for this board is 09-00183-xx.

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

expansion slots; two 16-bit/VL-Bus expansion slots; four sockets for SIMMs; a ZIF socket

for an OverDrive CPU; IDE interface connector; one floppy connector; two serial

port connectors; one parallel port connector.

The VESA Local Bus speed is determined by the CPU speed. If the CPU is a 486SX-25, or 486DX2-50, the VL-Bus

bus speed is 25MHz. If the CPU is a 486SX-33, 486DX-33, or 486DX2-66, the VL-Bus

bus speed is 33MHz. A 50 MHZ CLK is not yet a current VESA standard specification

The ISA bus speed for this motherboard is set at 8.33MHz. The CPU clock speed is

determined by the Oscillator. If the CPU is a 486SX-25, or 486DX2-50, the Bus

clock speed is 1/3. For the 486SX-33, 486DX-33, or 486DX2-66 CPUs, the Bus

clock speed is 1/4.

The following shows all of the possible memory configurations.

MEMORY CHART CONFIGURATION

===================================

Memory Banks

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

MB 0 1 2 3

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

1MB 1M

2MB 1M 1M

4MB 4M

6MB 1M 1M 4M

8MB 4M 4M

10MB 1M 1M 4M 4M

12MB 4M 4M 4M

16MB 4M 4M 4M 4M

16MB 16M

18MB 1M 1M 16M

20MB 4M 16M

24MB 4M 4M 16M

32MB 16M 16M

36MB 4M 16M 16M

40MB 4M 4M 16M 16M

48MB 16M 16M 16M

64MB 16M 16M 16M 16M

In the table above, 1M indicates that one 256x36 SIMM is installed in the socket,

4M indicates that one 1Mx36 SIMM is installed in the socket, 16M indicates that,

one 4Mx36 SIMM is installed in the socket.

Micronics Computers has tested and verified the following 1Mx36 memory brands:

Micron Technologies, Mitsubishi, Samsung, Texas Instruments, Toshiba

Micronics Computers has tested and verified the following 4Mx36 memory brands:

Mitsubishi, Samsung, Toshiba

+======================================+

+ MOTHERBOARD SWITCH & JUMPER SETTINGS +

+======================================+

DIP switch settings for CPU selection

=====================================

DIP Switch 1

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

CPU Speed S1 S2 S3 S4

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

33MHz or DX2/ 66MHz Off On Off Off

25MHz or DX2/ 50MHz On On Off Off

40MHZ or DX2/ 80MHZ On Off Off Off

50MHZ Off Off Off Off

The 40 and 50MHZ saettings are not documented by Micronics and are included here as a result of empirical data.

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

W70 CPU selection

Pins 2-3 486DX, 486DX2 & P24T

Pins 1-2 486SX

W71 PQFP Surface mounted 486SX

Pins 1-2 PQFP 486SX with Overdrive SX Installed

Pins 2-3 PQFP 486SX with DX, or DX2 CPU Installed

W40 When Local Bus Master controllers are installed {VL SCSI},

jumper W40 must be removed to support local bus DMA.

J12 Serial 16450 Port A

J16 Serial 16450 Port B

J15 Parallel Printer Port

W5 Parallel port I/O direction

Pins 2-3 Output mode (default)

Pins 1-2 Input mode (Scanner)

I/O Port addresses / CMOS Setup

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

COM1 3F8h IRQ 4

COM2 2F8h 3

COM3 3E8h 4

COM4 2E8h 3

LPT1 3BCh 7

LPT2 378h 7

LPT3 278h 7

IRQ in use

--------

IRQ 6 Floppy controller

IRQ 14 Primary IDE controller

J18 Floppy connector

J17 Primary IDE connector

W11 IDE LED

Pin 1 - Signal

Pin 2 - Ground

W31 Clearing CMOS Setup

Temporarily install jumper, normal settings are open.

J6 Optional External 4.5-6.0 volt battery connector {Motorola 146818AP RTC Only}

Pin 1 - Battery Positive

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Ground

The JX30 Motherboard does not require an external battery to be installed.

The Dallas / Benchmarq Real Time Clock Chip contains an internal battery for an approximate lifetime of 8-10 years.

W6 Color / Monochrome Display

COLOR - Installed *

MONO - Open

J33 External speaker

Pin 1 - Speaker

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - +5 volts DC

J34 Keylock / Power LED

Pin 1 - Power LED signal

Pin 2 - no connector

Pin 3 - Ground

Pin 4 - Keyboard lock signal

Pin 5 - Ground

W12 Reset switch

Pin 1 - Signal

Pin 2 - Ground

W13 Turbo LED

Pin 1 - Signal

Pin 2 - Ground

W14 Turbo switch

Pin 1 - Signal

Pin 2 - Ground

W8 Flash ROM operation (see note below)

Pins 1-2 Recovery mode

Pins 2-3 Normal operation (default)

DO NOT change jumper W8 unless instructed by a Micronics Technical Support Engineer.

Changing the jumper will result in the Bios being Erased. You must have a Flash

recovery floppy diskette before attempting to recover. The jumper is NOT moved when

updating the Flash ROM.

+=============================+

+ +

+ Cache Configuration +

+ Direct Mapped Write Through +

+ +

+=============================+

W64 W65 W66 W67 W68

64K Cache 1-2 1-2 2-3 2-3 1-2 (9) 8k X8 Sram -20Ns for U202, U203, U204, U205, U206, U207, U208, U209 & U201

128k 2-3 1-2 1-2 1-2 2-3 (5) 32kX8 Sram -20Ns for U202, U203, U204, U205, & U201

256k 2-3 2-3 2-3 2-3 2-3 (9) 32kX8 Sram -20ns for U202, U203, U204, U205, U206, U207, U208, U209 & U201