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# ISA/EISA, INC.
486B
Processor 80486SX/80487SX/80486DX
Processor Speed 20/33MHz
Chip Set OPTI
Max. Onboard DRAM 32MB
SRAM Cache 64/256KB
BIOS AMI
Dimensions 330mm x 218mm
I/O Options None
NPU Options 4167
IMG IMG 1
+------------------------------------------------------------+
| CONNECTIONS |
|------------------------------------------------------------|
| Purpose | Location | Purpose | Location |
|-------------------+----------+------------------+----------|
| Power LED & | J1 | Turbo switch | JP2 |
| keylock | | | |
|-------------------+----------+------------------+----------|
| Speaker | J3 | Turbo LED | JP21 |
|-------------------+----------+------------------+----------|
| External battery | J4 | Cooling fan | JP25 |
| | | switch | |
|-------------------+----------+------------------+----------|
| Reset switch | JP1 | Cooling fan | USP8 |
| | | power | |
+------------------------------------------------------------+
+------------------------------------------------------------+
| USER CONFIGURABLE SETTINGS |
|------------------------------------------------------------|
| Function | Jumper | Position |
|--------------------------------------+--------+------------|
| » | Factory configured - do not | JP10 | unknown |
| | alter | | |
|---+----------------------------------+--------+------------|
| » | CPU speed select switchable at | JP12 | pins 1 & 2 |
| | keyboard | | closed |
|---+----------------------------------+--------+------------|
| | CPU speed select switchable at | JP12 | pins 2 & 3 |
| | turbo switch | | closed |
|---+----------------------------------+--------+------------|
| » | Factory configured - do not | JP26 | open |
| | alter | | |
|---+----------------------------------+--------+------------|
| » | Video BIOS shadow before | JP27 | pins 1 & 2 |
| | initialization | | closed |
|---+----------------------------------+--------+------------|
| | Video BIOS shadow after | JP27 | pins 2 & 3 |
| | initialization | | closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU JUMPER CONFIGURATION |
|------------------------------------------------------------|
| CPU | JP22 | JP23 | JP24 |
|----------+------------+------------+-----------------------|
| 80486DX | pins 1 & 2 | pins 1 & 2 | pins 1 & 2 and 3 & 4 |
| (33MHz) | closed | closed | closed |
|----------+------------+------------+-----------------------|
| 80487SX | pins 3 & 4 | pins 2 & 3 | pins 1 & 2 and 3 & 4 |
| (20MHz) | closed | closed | closed |
|----------+------------+------------+-----------------------|
| 80486SX | pins 2 & 3 | pins 2 & 3 | pins 2 & 3 closed |
| (20MHz) | closed | closed | |
+------------------------------------------------------------+
+------------------------------------------------------------+
| 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) 1M x 9 | (4) 256K x 9 |
|------------------+--------------------+--------------------|
| 8MB | (4) 1M x 9 | (4) 1M x 9 |
|------------------+--------------------+--------------------|
| 16MB | (4) 4M x 9 | NONE |
|------------------+--------------------+--------------------|
| 17MB | (4) 4M x 9 | (4) 256K x 9 |
|------------------+--------------------+--------------------|
| 20MB | (4) 1M x 9 | (4) 4M x 9 |
|------------------+--------------------+--------------------|
| 20MB | (4) 4M x 9 | (4) 1M x 9 |
|------------------+--------------------+--------------------|
| 32MB | (4) 4M x 9 | (4) 4M x 9 |
+------------------------------------------------------------+
+------------------------------------------------------------+
| SRAM JUMPER CONFIGURATION |
|------------------------------------------------------------|
| Size | JP6 | JP7 | JP8 | JP9 | JP20 |
|-----------+------------+--------+--------+--------+--------|
| 64KB | pins 1 & 2 | pins 1 | pins 1 | pins 1 | pins 1 |
| | | & 2 | & 2 | & 2 | & 2 |
|-----------+------------+--------+--------+--------+--------|
| 256KB | pins 2 & 3 | pins 2 | pins 2 | pins 2 | pins 1 |
| | | & 3 | & 3 | & 3 | & 2 |
|-----------+------------+--------+--------+--------+--------|
| Disabled | N/A | N/A | N/A | N/A | pins 2 |
| | | | | | & 3 |
|------------------------------------------------------------|
| Note:Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| SRAM CONFIGURATION |
|------------------------------------------------------------|
| Size | Cache SRAM | TAG |
|------------------+--------------------+--------------------|
| 64KB | (8) 8K x 8 | (1) 8K x 8 |
|------------------+--------------------+--------------------|
| 256KB | (8) 32K x 8 | (1) 32K x 8 |
+------------------------------------------------------------+
+------------------------------------------------------------+
| I/O BUS SPEED JUMPER CONFIGURATION |
|------------------------------------------------------------|
|Bus Speed| JP3 | JP4 | JP5 | JP13 | JP14 | JP15 |
|---------+--------+--------+--------+-------+-------+-------|
| CPU/8 | open | open | open | open | open |closed |
|---------+--------+--------+--------+-------+-------+-------|
| CPU/6 | open | open | open | open |closed | open |
|---------+--------+--------+--------+-------+-------+-------|
| CPU/5 | open | open | open |closed | open | open |
|---------+--------+--------+--------+-------+-------+-------|
| CPU/4 | open | open | closed | open | open | open |
|---------+--------+--------+--------+-------+-------+-------|
| CPU/3 | open | closed | open | open | open | open |
|---------+--------+--------+--------+-------+-------+-------|
| CPU/2 | closed | open | open | open | open | open |
+------------------------------------------------------------+