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# J-MARK COMPUTER CORPORATION
486SX/DX VERSION II
Processor 80486SX/80487SX/80486DX/80486DX2
Processor Speed 16/20/25/33/50(internal)/50/66(internal) MHz
Chip Set OPTI
Max. onboard DRAM 32MB
Cache 64/128/256KB
BIOS AMI
Dimensions 240mm x 220mm
I/O Options None
NPU Options None
IMG IMG 1
+------------------------------------------------------------+
| CONNECTIONS |
|------------------------------------------------------------|
| Purpose | Location | Purpose | Location |
|------------------+----------+-------------------+----------|
| External battery | J1 | Speaker | J17 |
|------------------+----------+-------------------+----------|
| Turbo switch | JP9 | Power LED & | J18 |
| | | keylock | |
|------------------+----------+-------------------+----------|
| Turbo LED | JP10 | Reset switch | SW1 |
+------------------------------------------------------------+
+------------------------------------------------------------+
| USER CONFIGURABLE SETTINGS |
|------------------------------------------------------------|
| Function | Jumper | Position |
|------------------------------------+--------+--------------|
| » | CMOS memory normal operation | JP1 | pins 1 & 2 |
| | | | closed |
|---+--------------------------------+--------+--------------|
| | CMOS memory clear | JP1 | pins 2 & 3 |
| | | | closed |
|---+--------------------------------+--------+--------------|
| » | Monitor type select color | JP2 | Closed |
|---+--------------------------------+--------+--------------|
| | Monitor type select monochrome | JP2 | Open |
+------------------------------------------------------------+
+------------------------------------------------------------+
| DRAM CONFIGURATION |
|------------------------------------------------------------|
| Size | Bank 0 | Bank 1 |
|------------------+--------------------+--------------------|
| 1MB | (4) 256K x 9 | NONE |
|------------------+--------------------+--------------------|
| 2MB | (4) 256K x 9 | (4) 256K x 9 |
|------------------+--------------------+--------------------|
| 4MB | (4) 1M x 9 | NONE |
|------------------+--------------------+--------------------|
| 5MB | (4) 256K x 9 | (4) 1M x 9 |
|------------------+--------------------+--------------------|
| 8MB | (4) 1M x 9 | (4) 1M x 9 |
|------------------+--------------------+--------------------|
| 16MB | (4) 4M x 9 | NONE |
|------------------+--------------------+--------------------|
| 20MB | (4) 1M x 9 | (4) 4M x 9 |
|------------------+--------------------+--------------------|
| 32MB | (4) 4M x 9 | (4) 4M x 9 |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CACHE CONFIGURATION |
|------------------------------------------------------------|
| Size | Bank 0 | Bank 1 | TAG (U39) | TAG (U40) |
|-------+-------------+------------+------------+------------|
| 64KB | (4) 8K x 8 | NONE | (1) 8K x 8 | NONE |
|-------+-------------+------------+------------+------------|
| 128KB | (4) 32K x 8 | NONE | (1) 8K x 8 | NONE |
|-------+-------------+------------+------------+------------|
| 256KB | (4) 32K x 8 | (4) 32K x | (1) 8K x 8 | (1) 8K x 8 |
| | | 8 | | |
|-------+-------------+------------+------------+------------|
| 256KB | (4) 32K x 8 | (4) 32K x | (1) 32K x | NONE |
| | | 8 | 8 | |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CACHE JUMPER CONFIGURATION |
|------------------------------------------------------------|
| Size | JP5 | JP6 | JP7 | JP8 | JP15 | JP16 |
|-------+--------+--------+--------+-------+--------+--------|
| 64KB | Open | Open | Open | pins | Open | Open |
| | | | | 2 & 3 | | |
|-------+--------+--------+--------+-------+--------+--------|
| 128KB | Closed | Open | Closed | pins | Open | Closed |
| | | | | 1 & 2 | | |
|-------+--------+--------+--------+-------+--------+--------|
| 256KB | Closed | Closed | Closed | pins | closed | closed |
| | | | | 2 & 3 | | |
|------------------------------------------------------------|
| Note:Pins designated should be in the closed postion. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU TYPE CONFIGURATION |
|------------------------------------------------------------|
| CPU type | JP17 | JP18 | JP19 | JP20 |
|--------------+--------+--------------+--------+------------|
| 80486SX PQFP | Open | Open | Closed | pins 2 & 3 |
| | | | | closed |
|--------------+--------+--------------+--------+------------|
| 80486SX PGA | Closed | Open | Closed | pins 2 & 3 |
| | | | | closed |
|--------------+--------+--------------+--------+------------|
| 80487SX | Closed | pins 2 & 3 | Closed | pins 1 & 2 |
| | | closed | | closed |
|--------------+--------+--------------+--------+------------|
| 80486DX/DX2 | Closed | pins 1 & 2 | Closed | pins 1 & 2 |
| | | closed | | closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED CONFIGURATION |
|------------------------------------------------------------|
| Speed | JP11 | JP12 | JP13 | JP14 |
|------------+-----------+-----------+-----------+-----------|
| 16MHz | Closed | Closed | Closed | Closed |
|------------+-----------+-----------+-----------+-----------|
| 20MHz | Open | Closed | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 25MHz | Open | Closed | Open | Closed |
|------------+-----------+-----------+-----------+-----------|
| 33MHz | Open | Open | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 50i MHz | Open | Closed | Open | Closed |
|------------+-----------+-----------+-----------+-----------|
| 50MHz | Open | Open | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 66i MHz | Open | Open | Closed | Open |
+------------------------------------------------------------+