MICRONICS MOTHERBOARD

80486xx VL JX30GC baby size (09-00203-xx)

This document is for the baby-sized (13.3" x 8.5") JX30GC VL-Bus motherboard.

The part number for this board is 09-00203-xx.

It's identifying features are: an LED between expansion slots #5 and #6

Seven 16-bit ISA expansion slots

Two 32-bit VL-Bus/ISA expansion slots

Four sockets for 72 pin x 36 bit SIMMs

A ZIF socket for an OverDrive CPU

Two 40 pin EIDE interface connectors.

One 34 pin floppy connector

Two 16650 based 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 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 i486DX/4 100 Mhz allows the system board and VL Bus to run at 33MHZ

The i486DX/4 75 Mhz allows the system board and VL Bus to run at 25MHZ

The ISA bus speed for this motherboard is set at 8.33MHz. The CPU clock speed is determined by the clock synthesizer. If the CPU is a 486SX-25, 486DX2-50, or 486DX4/75 the Bus

clock speed is 1/3. For the 486SX-33, 486DX-33, 486DX2-66 and i486DX4/100 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 1 settings for CPU selection

CPU CLK Speed				S1	S2	S3	S4
33MHz :DX/33, DX2/66, DX4/100MHz	On	On	Off	Off
25MHz :DX/25, DX2/50, DX4/75 MHz	Off	On	Off	Off


W12 CPU selection

Pins 2-3 486DX, 486DX2, 486DX/4 & P24T

Pins 1-2 486SX


W13 PQFP Surface mounted 486SX

Pins 1-2 PQFP 486SX Enabled

Pins 2-3 PQFP 486SX Disabled


W4 When Local Bus Master controllers are installed {VL SCSI}, jumper W4 must be removed to support local bus DMA.


J14 Serial 16550 Port A SMC Super I/O FDC37c665

J9 Serial 16550 Port B SMC Super I/O FDC37c665

J16 Parallel Printer Port

W36 Parallel Printer port IRQ selection

1-2: IRQ 7

2-3: IRQ 5

W37, W38 Reserved / No jumpers installed


I/O Port addresses / CMOS Setup

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

COM1 	3F8h IRQ 4
COM2 	2F8h IRQ 3
COM3 	3E8h IRQ 4
COM4 	2E8h IRQ 3
LPT1 	378h IRQ 7 /5
LPT2 	278h IRQ 7 /5

IRQ in use {Autodisable if other controllers needs to use IRQs}

--------

IRQ 6 	Floppy controller
IRQ 14	Primary IDE controller
IRQ 15 Secondary IDE controller
J27 	Floppy connector
J26 	Primary IDE connector
J32 	Secondary IDE connector
W21 	IDE LED
	Pin 1 - Signal
	Pin 2 - Ground
W5 	Clearing CMOS Setup
Temporarily install jumper, normal settings are open.
J8 	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 JX30GC 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.
W2 	Color / Monochrome Display
	COLOR - Installed *
	MONO - Open
J30 	External speaker
	Pin 1 - Speaker
	Pin 2 - no connector
	Pin 3 - Ground
	Pin 4 - +5 volts DC
J31 	Keylock / Power LED
	Pin 1 - Power LED signal
	Pin 2 - no connector
	Pin 3 - Ground
	Pin 4 - Keyboard lock signal
	Pin 5 - Ground
W20 	Reset switch
	Pin 1 - Signal
	Pin 2 - Ground
W18 	Turbo LED
	Pin 1 - Signal
	Pin 2 - Ground
W19 	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.


WRITE THROUGH CACHE JUMPER CONFIGURATION

	W10	W11	W22	W23	W24
64K	1-2	1-2	2-3	2-3	1-2
(9) 8k X8 Sram -20Ns for U56-U60, U67-U70, & U34 / TAG
128k	1-2	2-3	1-2	1-2	2-3 
(5) 32kX8 Sram -20Ns for U56-U60, & U34 / TAG
256k	2-3	2-3	2-3	2-3	2-3 
(9) 32kX8 Sram -20ns for U56-U60, U67-U70, & U34 / TAG

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

WRITE BACK CACHE JUMPER CONFIGURATION CONFIGURATION

	W16	 W17
64K	1-2	2-3 (1) 8k X8 Sram -20Ns for U61
128k	1-2	2-3 (1) 32kX8 Sram -20Ns for U61
256k	2-3	2-3 (1) 32kX8 Sram -20ns for U61