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
expansion slots; two 32-bit VL-Bus/ISA 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 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 settings for CPU selection
=====================================
DIP Switch 1
----------------------
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 3
COM3 3E8h 4
COM4 2E8h 3
LPT1 378h 7 /5
LPT2 278h 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.
+=============================+
+ +
+ Cache Configuration +
+ Direct Mapped Write Through +
+ +
+=============================+
W10 W11 W22 W23 W24
64K Cache 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
256k 2-3 2-3 2-3 2-3 2-3 (9) 32kX8 Sram -20ns for U56-U60, U67-U70, & U34
+=============================+
+ +
+ Cache Configuration +
+ Direct Mapped Write Back +
+ +
+=============================+
W16 W17
64K Cache 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