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# TYAN COMPUTER CORPORATION
S1571
Device Type Mainboard
Processor CX 6X86/CX 6X86L/CX 686MX/AM K5/AM K6/Pentium
Processor Speed 75/90/100/120/133/150/166/200/233MHz
Chip Set Intel
Video Chip Set None
Maximum Onboard 256MB (EDO & SDRAM supported)
Memory
Maximum Video None
Memory
Cache 512KB
BIOS AMI, Award
Dimensions 330mm x 218mm
I/O Options 32-bit PCI slots (5), floppy drive interface,
green PC connector, IDE interfaces (2),
parallel port, PS/2 mouse interface, serial
ports (2), IR connectors (2), USB connectors
(2)
NPU Options None
(IMG) IMG 1
+------------------------------------------------------------+
| CONNECTIONS |
|------------------------------------------------------------|
| Purpose | Location | Purpose | Location |
|----------------+-------------+---------------+-------------|
| Serial port 1 | CN1 | IR connector | JP17/pins 6 |
| | | | - 9 |
|----------------+-------------+---------------+-------------|
| Serial port 2 | CN2 | IDE interface | JP17/pins |
| | | LED 1 | 13 & 14 |
|----------------+-------------+---------------+-------------|
| Floppy drive | CN3 | IDE interface | JP17/pins |
| interface | | LED 2 | 15 & 16 |
|----------------+-------------+---------------+-------------|
| Parallel port | CN4 | Power LED | JP17/pins |
| | | | 18 - 20 |
|----------------+-------------+---------------+-------------|
| IDE interface | CN5 | Reset switch | JP17/pins |
| 2 | | | 22 & 23 |
|----------------+-------------+---------------+-------------|
| IDE interface | CN6 | Speaker | JP17/pins |
| 1 | | | 24 - 27 |
|----------------+-------------+---------------+-------------|
| PS/2 mouse | CN7 | Turbo LED | JP24 |
| interface | | | |
|----------------+-------------+---------------+-------------|
| Chassis fan | FAN1 | Turbo switch | JP25 |
| power | | | |
|----------------+-------------+---------------+-------------|
| Chassis fan | FAN2 | Keylock | JP26/pins 4 |
| power | | | & 5 |
|----------------+-------------+---------------+-------------|
| Chassis fan | FAN3 | 32-bit PCI | PC1 – PC5 |
| power | | slots | |
|----------------+-------------+---------------+-------------|
| IR connector | IR1 | USB connector | USB1 |
| | | 1 | |
|----------------+-------------+---------------+-------------|
| Green PC | JP17/pins 3 | USB connector | USB2 |
| connector | & 4 | 2 | |
+------------------------------------------------------------+
+------------------------------------------------------------+
| USER CONFIGURABLE SETTINGS |
|------------------------------------------------------------|
| Function | Label | Position |
|-------------------------------------+-------+--------------|
| » | Factory configured - do not | J22 | Unidentified |
| | alter | | |
|---+---------------------------------+-------+--------------|
| » | Factory configured - do not | J23 | Unidentified |
| | alter | | |
|---+---------------------------------+-------+--------------|
| » | Factory configured - do not | JP21 | Unidentified |
| | alter | | |
|---+---------------------------------+-------+--------------|
| » | CMOS memory normal operation | JP22 | Pins 1 & 2 |
| | | | closed |
|---+---------------------------------+-------+--------------|
| | CMOS memory clear | JP22 | Pins 2 & 3 |
| | | | closed |
|---+---------------------------------+-------+--------------|
| | Flash BIOS voltage select 12v | JP23 | Pins 2 & 3 |
| | | | closed |
|---+---------------------------------+-------+--------------|
| | Flash BIOS voltage select 5v | JP23 | Pins 1 & 2 |
| | | | closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| SIMM CONFIGURATION |
|------------------------------------------------------------|
| Size | Bank 0 | Bank 1 | Bank 2 |
|------------+---------------+---------------+---------------|
| 8MB | (2) 1M x36 | None | None |
|------------+---------------+---------------+---------------|
| 16MB | (2) 2M x36 | None | None |
|------------+---------------+---------------+---------------|
| 16MB | (2) 1M x36 | (2) 1M x36 | None |
|------------+---------------+---------------+---------------|
| 24MB | (2) 2M x36 | (2) 1M x36 | None |
|------------+---------------+---------------+---------------|
| 24MB | (2) 1M x36 | (2) 1M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 32MB | (2) 4M x36 | None | None |
|------------+---------------+---------------+---------------|
| 32MB | (2) 2M x36 | (2) 1M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 32MB | (2) 2M x36 | (2) 2M x36 | None |
|------------+---------------+---------------+---------------|
| 40MB | (2) 4M x36 | (2) 1M x36 | None |
+------------------------------------------------------------+
+------------------------------------------------------------+
| SIMM CONFIGURATION (CON’T) |
|------------------------------------------------------------|
| Size | Bank 0 | Bank 1 | Bank 2 |
|------------+---------------+---------------+---------------|
| 40MB | (2) 2M x36 | (2) 2M x32 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 48MB | (2) 4M x36 | (2) 1M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 48MB | (2) 4M x36 | (2) 2M x36 | None |
|------------+---------------+---------------+---------------|
| 48MB | (2) 2M x36 | (2) 2M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 56MB | (2) 4M x36 | (2) 2M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 64MB | (2) 8M x36 | None | None |
|------------+---------------+---------------+---------------|
| 64MB | (2) 4M x36 | (2) 2M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 64MB | (2) 4M x36 | (2) 4M x36 | None |
|------------+---------------+---------------+---------------|
| 80MB | (2) 8M x36 | (2) 1M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 80MB | (2) 8M x36 | (2) 2M x32 | None |
|------------+---------------+---------------+---------------|
| 80MB | (2) 4M x36 | (2) 4M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 88MB | (2) 8M x36 | (2) 2M x32 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 96MB | (2) 8M x36 | (2) 2M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 96MB | (2) 8M x36 | (2) 4M x36 | None |
|------------+---------------+---------------+---------------|
| 96MB | (2) 4M x36 | (2) 4M x36 | (2) 4M x36 |
|------------+---------------+---------------+---------------|
| 104MB | (2) 8M x36 | (2) 4M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 112MB | (2) 8M x36 | (2) 4M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 128MB | (2) 16M x36 | None | None |
|------------+---------------+---------------+---------------|
| 128MB | (2) 8M x36 | (2) 4M x36 | (2) 4M x36 |
|------------+---------------+---------------+---------------|
| 128MB | (2) 8M x36 | (2) 8M x36 | None |
|------------+---------------+---------------+---------------|
| 136MB | (2) 16M x36 | (2) 1M x36 | None |
|------------+---------------+---------------+---------------|
| 144MB | (2) 16M x36 | (2) 2M x32 | None |
|------------+---------------+---------------+---------------|
| 144MB | (2) 8M x36 | (2) 8M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 152MB | (2) 16M x36 | (2) 2M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 160MB | (2) 16M x36 | (2) 2M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 160MB | (2) 16M x36 | (2) 4M x36 | None |
|------------+---------------+---------------+---------------|
| 160MB | (2) 8M x36 | (2) 8M x36 | (2) 4M x36 |
|------------+---------------+---------------+---------------|
| 176MB | (2) 16M x36 | (2) 4M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 192MB | (2) 16M x36 | (2) 4M x36 | (2) 4M x36 |
|------------+---------------+---------------+---------------|
| 192MB | (2) 16M x36 | (2) 8M x36 | None |
|------------+---------------+---------------+---------------|
| 192MB | (2) 8M x36 | (2) 8M x36 | (2) 8M x36 |
|------------+---------------+---------------+---------------|
| 200MB | (2) 16M x36 | (2) 8M x36 | (2) 1M x36 |
|------------+---------------+---------------+---------------|
| 208MB | (2) 16M x36 | (2) 8M x36 | (2) 2M x36 |
|------------+---------------+---------------+---------------|
| 224MB | (2) 16M x36 | (2) 8M x36 | (2) 4M x36 |
|------------+---------------+---------------+---------------|
| 256MB | (2) 16M x36 | (2) 8M x36 | (2) 8M x36 |
|------------------------------------------------------------|
| Note: Board accepts EDO memory. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| DIMM CONFIGURATION |
|------------------------------------------------------------|
| Size | Bank 3 | Bank 4 |
|------------------+--------------------+--------------------|
| 8MB | (2) 1M x32 | None |
|------------------+--------------------+--------------------|
| 16MB | (2) 2M x32 | None |
|------------------+--------------------+--------------------|
| 16MB | (2) 1M x32 | (2) 1M x32 |
|------------------+--------------------+--------------------|
| 24MB | (2) 2M x32 | (2) 1M x32 |
|------------------+--------------------+--------------------|
| 32MB | (2) 4M x36 | None |
|------------------+--------------------+--------------------|
| 32MB | (2) 2M x32 | (2) 2M x32 |
|------------------+--------------------+--------------------|
| 40MB | (2) 4M x36 | (2) 1M x32 |
|------------------+--------------------+--------------------|
| 48MB | (2) 4M x36 | (2) 2M x32 |
|------------------+--------------------+--------------------|
| 64MB | (2) 8M x36 | None |
|------------------+--------------------+--------------------|
| 64MB | (2) 4M x36 | (2) 4M x36 |
|------------------+--------------------+--------------------|
| 72MB | (2) 8M x36 | (2) 1M x32 |
|------------------+--------------------+--------------------|
| 80MB | (2) 8M x36 | (2) 2M x32 |
|------------------+--------------------+--------------------|
| 96MB | (2) 8M x36 | (2) 4M x36 |
|------------------+--------------------+--------------------|
| 128MB | (2) 16M x36 | None |
|------------------+--------------------+--------------------|
| 128MB | (2) 8M x36 | (2) 8M x36 |
|------------------+--------------------+--------------------|
| 136MB | (2) 16M x36 | (2) 1M x32 |
|------------------+--------------------+--------------------|
| 144MB | (2) 16M x36 | (2) 2M x32 |
|------------------+--------------------+--------------------|
| 160MB | (2) 16M x36 | (2) 4M x36 |
|------------------+--------------------+--------------------|
| 192MB | (2) 16M x36 | (2) 8M x36 |
|------------------+--------------------+--------------------|
| 256MB | (2) 16M x36 | (2) 16M x36 |
|------------------------------------------------------------|
| Note: Board accepts SDRAM memory. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| SIMM VOLTAGE CONFIGURATION |
|------------------------------------------------------------|
| Voltage | JP1 | JP2 | JP7 | JP8 |
|------------+-----------+-----------+-----------+-----------|
| 3v | Open | Open | Closed | Closed |
|------------+-----------+-----------+-----------+-----------|
| 5v | Closed | Closed | Open | Open |
+------------------------------------------------------------+
+------------------------------------------------------------+
| DIMM VOLTAGE CONFIGURATION |
|------------------------------------------------------------|
| Voltage | JP3 | JP4 | JP5 | JP6 |
|------------+-----------+-----------+-----------+-----------|
| 3v | Open | Open | Closed | Closed |
|------------+-----------+-----------+-----------+-----------|
| 5v | Closed | Closed | Open | Open |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CACHE CONFIGURATION |
|------------------------------------------------------------|
| Size | Bank 0 |
|----------------------------+-------------------------------|
| 512KB | (2) 64K x 32 |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (CX 6X86) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 |BF1 |BF2 |JP9 | JP10 |JP15 |
| speed |speed | | | | | | | |
|-------+------+----------+------+----+----+----+------+-----|
|120MHz |50MHz | 2x |Closed|Open|Open|1 & |Closed|1 & 2|
| | | | | | |2, 3| | |
| | | | | | |& 4 | | |
|-------+------+----------+------+----+----+----+------+-----|
|133MHz |55MHz | 2x |Closed|Open|Open|1 & | Open |1 & 2|
| | | | | | |2, 3| | |
| | | | | | |& 4 | | |
|-------+------+----------+------+----+----+----+------+-----|
|150MHz |60MHz | 2x |Closed|Open|Open|3 & |Closed|1 & 2|
| | | | | | | 4 | | |
|-------+------+----------+------+----+----+----+------+-----|
|166MHz |66MHz | 2x |Closed|Open|Open|1 & |Closed|1 & 2|
| | | | | | | 2 | | |
|-------+------+----------+------+----+----+----+------+-----|
|200MHz |75MHz | 2x |Closed|Open|Open|3 & | Open |1 & 2|
| | | | | | | 4 | | |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (CX 6X86L) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 |BF1 |BF2 |JP9 | JP10 |JP15 |
| speed |speed | | | | | | | |
|-------+------+----------+------+----+----+----+------+-----|
|150MHz |60MHz | 2x |Closed|Open|Open|3 & |Closed|1 & 2|
| | | | | | | 4 | | |
|-------+------+----------+------+----+----+----+------+-----|
|166MHz |66MHz | 2x |Closed|Open|Open|1 & |Closed|1 & 2|
| | | | | | | 2 | | |
|-------+------+----------+------+----+----+----+------+-----|
|200MHz |75MHz | 2x |Closed|Open|Open|3 & | Open |1 & 2|
| | | | | | | 4 | | |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (CX 6X86MX) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 | BF1 |BF2 |JP9| JP10 |JP15|
| speed |speed | | | | | | | |
|-------+------+----------+------+------+----+---+------+----|
|166MHz |60MHz | 2x |Closed|Closed|Open|3 &|Closed|1 & |
| | | | | | | 4 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|200MHz |66MHz | 2x |Closed|Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|233MHz |75MHz | 2x |Closed|Closed|Open|3 &| Open |1 & |
| | | | | | | 4 | | 2 |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (AM K5) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 | BF1 |BF2 |JP9| JP10 |JP15|
| speed |speed | | | | | | | |
|-------+------+----------+------+------+----+---+------+----|
| 90MHz |60MHz | 1.5x | Open | Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|100MHz |66MHz | 1.5x | Open | Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|120MHz |60MHz | 2x |Closed| Open |Open|3 &|Closed|1 & |
| | | | | | | 4 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|133MHz |66MHz | 2x |Closed| Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|166MHz |66MHz | 2.5x |Closed|Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (AM K6) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 | BF1 |BF2 |JP9| JP10 |JP15|
| speed |speed | | | | | | | |
|-------+------+----------+------+------+----+---+------+----|
|166MHz |66MHz | 2.5x |Closed|Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|200MHz |66MHz | 3x | Open |Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|233MHz |66MHz | 3.5x | Open | Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (IDT C6) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier|BF0 | BF1 |BF2 |JP9 | JP10 |JP15 |
| speed |speed | | | | | | | |
|-------+------+----------+----+------+----+----+------+-----|
|150MHz |50MHz | 3x |Open|Closed|Open|1 & |Closed|1 & 2|
| | | | | | |2, 3| | |
| | | | | | |& 4 | | |
|-------+------+----------+----+------+----+----+------+-----|
|180MHz |66MHz | 3x |Open|Closed|Open|3 & |Closed|1 & 2|
| | | | | | | 4 | | |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (INTEL) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 | BF1 |BF2 |JP9| JP10 |JP15|
| speed |speed | | | | | | | |
|-------+------+----------+------+------+----+---+------+----|
| 75MHz |50MHz | 1.5x | Open | Open |Open|1 &|Closed|1 & |
| | | | | | |2, | | 2 |
| | | | | | |3 &| | |
| | | | | | | 4 | | |
|-------+------+----------+------+------+----+---+------+----|
| 90MHz |60MHz | 1.5x | Open | Open |Open|3 &|Closed|1 & |
| | | | | | | 4 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|100MHz |66MHz | 1.5x | Open | Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|120MHz |60MHz | 2x |Closed| Open |Open|3 &|Closed|1 & |
| | | | | | | 4 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|133MHz |66MHz | 2x |Closed| Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|150MHz |60MHz | 2.5x |Closed|Closed|Open|3 &|Closed|1 & |
| | | | | | | 4 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|166MHz |66MHz | 2.5x |Closed|Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|200MHz |66MHz | 3x | Open |Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU SPEED SELECTION (INTEL MMX) |
|------------------------------------------------------------|
| CPU |Clock |Multiplier| BF0 | BF1 |BF2 |JP9| JP10 |JP15|
| speed |speed | | | | | | | |
|-------+------+----------+------+------+----+---+------+----|
|166MHz |66MHz | 2.5x |Closed|Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|200MHz |66MHz | 3x | Open |Closed|Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|-------+------+----------+------+------+----+---+------+----|
|233MHz |66MHz | 3.5x | Open | Open |Open|1 &|Closed|1 & |
| | | | | | | 2 | | 2 |
|------------------------------------------------------------|
|Note: Pins designated should be in the closed position. |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU TYPE SELECTION |
|------------------------------------------------------------|
| Type | VIO |
|-------------------------------+----------------------------|
| AM K5 | Open |
|-------------------------------+----------------------------|
| AM K6 | Closed |
|-------------------------------+----------------------------|
| CX 6X86 | Closed |
|-------------------------------+----------------------------|
| CX 6X86L | Closed |
|-------------------------------+----------------------------|
| CX 6X86MX | Closed |
|-------------------------------+----------------------------|
| IDT C6 | Open |
|-------------------------------+----------------------------|
| P54C | Open |
|-------------------------------+----------------------------|
| P55C | Closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| CPU VOLTAGE SELECTION |
|------------------------------------------------------------|
| Voltage | VID0 | VID1 | VID2 | VID3 |
|------------+-----------+-----------+-----------+-----------|
| 2.0v | Open | Open | Open | Open |
|------------+-----------+-----------+-----------+-----------|
| 2.1v | Open | Open | Open | Closed |
|------------+-----------+-----------+-----------+-----------|
| 2.2v | Open | Open | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 2.3v | Open | Open | Closed | Closed |
|------------+-----------+-----------+-----------+-----------|
| 2.4v | Open | Closed | Open | Open |
|------------+-----------+-----------+-----------+-----------|
| 2.5v | Open | Closed | Open | Closed |
|------------+-----------+-----------+-----------+-----------|
| 2.6v | Open | Closed | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 2.7v | Open | Closed | Closed | Closed |
|------------+-----------+-----------+-----------+-----------|
| 2.8v | Closed | Open | Open | Open |
|------------+-----------+-----------+-----------+-----------|
| 2.9v | Closed | Open | Open | Closed |
|------------+-----------+-----------+-----------+-----------|
| 3.0v | Closed | Open | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 3.1v | Closed | Open | Closed | Closed |
|------------+-----------+-----------+-----------+-----------|
| 3.2v | Closed | Closed | Open | Open |
|------------+-----------+-----------+-----------+-----------|
| 3.3v | Closed | Closed | Open | Closed |
|------------+-----------+-----------+-----------+-----------|
| 3.4v | Closed | Closed | Closed | Open |
|------------+-----------+-----------+-----------+-----------|
| 3.5v | Closed | Closed | Closed | Closed |
+------------------------------------------------------------+
+------------------------------------------------------------+
| SERIAL PORT SELECTION |
|------------------------------------------------------------|
| Setting | JP16 | JP17 |
|--------------------+-------------------+-------------------|
| Used as serial | Pins 1 & 2 closed | Pins 1 & 2 closed |
| port | | |
|--------------------+-------------------+-------------------|
| Used as IR port | Pins 2 & 3 closed | Pins 2 & 3 closed |
+------------------------------------------------------------+