SCIENTIFIC MICRO SYSTEMS
========================

   OMTI 8640

   Data bus: 16-bit, ISA

   Size: Full-length, full-height card

   Hard drives supported:  Two ESDI RLL drives

   Floppy drives supported: Four 360KB, 720KB, 1.2MB,or 1.44MB

   Sector interleave: 1:1

   Maximum heads/cyl.: 16 heads and 2048 cylinders

<gopher://bitreich.org/I/th99/c/S-T/20189-1.png>
   

   +------------------------------------------------------------+
   |                        CONNECTIONS                         |
   |------------------------------------------------------------|
   |                    Function                    | Location  |
   |------------------------------------------------+-----------|
   | 34-pin data cable connector-floppy drive 1 & 2 |    J1     |
   |------------------------------------------------+-----------|
   | 34-pin data cable connector-floppy drive 3 & 4 |    J2     |
   |------------------------------------------------+-----------|
   | 20-pin data cable connector-drive 0            |    J3     |
   |------------------------------------------------+-----------|
   | 20-pin data cable connector-drive 1            |    J4     |
   |------------------------------------------------+-----------|
   | 34-pin control cable connector-hard drive      |    J5     |
   |------------------------------------------------+-----------|
   | 4-pin connector-drive active LED               |    J6     |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                 USER CONFIGURABLE SETTINGS                 |
   |------------------------------------------------------------|
   |              Function              | Location |  Setting   |
   |------------------------------------+----------+------------|
   |>> | Floppy drive port address is   |    W2    |    open    |
   |   | 3F0-3F7h                       |          |            |
   |---+--------------------------------+----------+------------|
   |   | Floppy drive port address is   |    W2    |   closed   |
   |   | 370-377h                       |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Hard drive port address is     |    W3    |    open    |
   |   | 1F0-1F7h                       |          |            |
   |---+--------------------------------+----------+------------|
   |   | Hard drive port address is     |    W3    |   closed   |
   |   | 170-177h                       |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Floppy enabled                 |    W5    |    open    |
   |---+--------------------------------+----------+------------|
   |   | Floppy drive disabled          |    W5    |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | SPT-read from drive            |   W16    |    open    |
   |---+--------------------------------+----------+------------|
   |   | SPT-calculate and set          |   W16    |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | Cache disabled                 |   W17    |    open    |
   |---+--------------------------------+----------+------------|
   |   | Cache enabled                  |   W17    |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | Track Offset Cmd. and Data     |   W18    |    open    |
   |   | Strobe Offset disabled         |          |            |
   |---+--------------------------------+----------+------------|
   |   | Track Offset Cmd. and Data     |   W18    |   closed   |
   |   | Strobe Offset enabled          |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Single speed floppy drive      |   W19    |    open    |
   |   | supported                      |          |            |
   |---+--------------------------------+----------+------------|
   |   | Dual speed floppy drive        |   W19    |   closed   |
   |   | Supported                      |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Floppy connector (CN1)         |   W20    | pins 1 & 2 |
   |   | polarity active high           |          |   closed   |
   |---+--------------------------------+----------+------------|
   |   | Floppy connector (CN1)         |   W20    | pins 2 & 3 |
   |   | polarity active low            |          |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | Floppy connector (CN1)         |   W21    | pins 1 & 2 |
   |   | polarity active high           |          |   closed   |
   |---+--------------------------------+----------+------------|
   |   | Floppy connector (CN1)         |   W21    | pins 2 & 3 |
   |   | polarity active low            |          |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | BIOS enabled                   |   W25    |   closed   |
   |---+--------------------------------+----------+------------|
   |   | BIOS disabled                  |   W25    |    open    |
   |---+--------------------------------+----------+------------|
   |>> | Chassis not grounded           |   W28    |    open    |
   |---+--------------------------------+----------+------------|
   |   | Chassis grounded               |   W28    |   closed   |
   |------------------------------------------------------------|
   | Note:W22, & W11-15 are not documented                      |
   +------------------------------------------------------------+

   +------------------------------------------------------------+
   |                        BIOS ADDRESS                        |
   |------------------------------------------------------------|
   |      Address       |    Jumper W23     |    Jumper W24     |
   |--------------------+-------------------+-------------------|
   |>> |     C8000h     |      closed       |      closed       |
   |---+----------------+-------------------+-------------------|
   |   |     CA000h     |      closed       |       open        |
   |---+----------------+-------------------+-------------------|
   |   |     CC000h     |       open        |      closed       |
   |---+----------------+-------------------+-------------------|
   |   |     CE000h     |       open        |       open        |
   +------------------------------------------------------------+