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# ABIT COMPUTER CORPORATION
AR4
Processor 80486SX/80487SX/80486DX/80486DX2
Processor Speed 40/50(internal)/60/66(internal)MHz
Chip Set ALI
Max. Onboard DRAM 32MB
Cache None
BIOS Award
Dimensions 330mm x 218mm
I/O Options None
NPU Options None
IMG IMG 1
+------------------------------------------------------------+
| CONNECTIONS |
|------------------------------------------------------------|
| Purpose | Location | Purpose | Location |
|-------------------+----------+------------------+----------|
| External battery | J4 | Turbo switch/LED | J21 |
|-------------------+----------+------------------+----------|
| Reset switch | J19 | Keylock | J22 |
|-------------------+----------+------------------+----------|
| Speaker | J20 | | |
+------------------------------------------------------------+
+------------------------------------------------------------+
| USER CONFIGURABLE SETTINGS |
|------------------------------------------------------------|
| Function | Jumper | Position |
|--------------------------------------+--------+------------|
| ยป | Monitor type select color | JP1 | pins 2 & 3 |
| | | | closed |
|---+----------------------------------+--------+------------|
| | Monitor type select monochrome | JP1 | pins 1 & 2 |
| | | | closed |
|---+----------------------------------+--------+------------|
| | Factory configured - do not | JP2 | on |
| | alter | | |
|---+----------------------------------+--------+------------|
| | CPU set at 80486SX (PQFP) | JP7 | pins 1 & 2 |
| | | | closed |
|---+----------------------------------+--------+------------|
| | CPU set at 80486SX (PGA) | JP7 | pins 2 & 3 |
| | | | 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 |
|------------------+--------------------+--------------------|
| 8MB | (4) 1M x 9 | (4) 1M x 9 |
|------------------+--------------------+--------------------|
| 16MB | (4) 4M x 9 | NONE |
|------------------+--------------------+--------------------|
| 32MB | (4) 4M x 9 | (4) 4M x 9 |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU TYPE CONFIGURATION |
|------------------------------------------------------------|
| CPU Type | JP4 | JP5 |
|------------------+--------------------+--------------------|
| 80486SX | Open | pin 1 & 2 closed |
|------------------+--------------------+--------------------|
| 80487SX | pins 1 & 2 closed | pins 2 & 3 closed |
|------------------+--------------------+--------------------|
| 80486DX | pins 2 & 3 closed | pins 2 & 3 closed |
|------------------+--------------------+--------------------|
| 80486DX2 | pins 2 & 3 closed | pins 2 & 3 closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| AT BUS CLOCK CONFIGURATION |
|------------------------------------------------------------|
| Speed | JP3 | JP6 |
|------------------+--------------------+--------------------|
| 40MHz | pins 2 & 3 closed | pins 1 & 2 closed |
|------------------+--------------------+--------------------|
| 50MHz | pins 1 & 2 closed | pins 2 & 3 closed |
|------------------+--------------------+--------------------|
| 66MHz | pins 1 & 2 closed | pins 1 & 2 closed |
+------------------------------------------------------------+