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

   OMTI 8150C, 8250, 8250C, 8157, 8257

   Data bus: 16-bit, ISA

   Size: Full-length, full-height card

   Hard drives supported:  OMTI 8150C/8250/8250C:Two MFM
   ST506/ST412 drives

              OMTI 8157/8257:Two RLL ST506/ST412 drives

   Floppy drives supported: OMTI 8150C/8157:None

              OMTI 8250/8250C/8257:Two 360KB, 720KB, 1.2MB,


   Sector interleave: 1:1

   Maximum heads/cyl.: 16 heads and 2048 cylinders

<gopher://bitreich.org/I/th99/c/S-T/20187-1.png>
   

   +------------------------------------------------------------+
   |                     CABLE CONNECTIONS                      |
   |------------------------------------------------------------|
   | 34-pin data cable connector-floppy drive (OMTI        | J1 |
   | 8250/C/8257 only)                                     |    |
   |-------------------------------------------------------+----|
   | 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   |
   |------------------------------------+----------+------------|
   |>> | Sysclk signal from AT bus      |    W7    | pins 1 & 2 |
   |   | input to 5098C chip            |          |   closed   |
   |---+--------------------------------+----------+------------|
   |   | No sysclk signal from bus,     |    W7    | pins 2 & 3 |
   |   | input tied low                 |          |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | Single speed floppy drives     |    W8    | pins 1 & 2 |
   |   | (OMTI 8250/8250C/8257 only)    |          |   closed   |
   |---+--------------------------------+----------+------------|
   |   | Dual speed floppy drives (OMTI |    W8    | pins 2 & 3 |
   |   | 8250/8250C/8257 only)          |          |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | Floppy precomp. values normal  |    W9    | pins 2 & 3 |
   |   | (8250/8250C/8257 only)         |          |   closed   |
   |---+--------------------------------+----------+------------|
   |   | Alt. floppy precomp. values    |    W9    | pins 1 & 2 |
   |   | (OMTI 8250/8250C/8257 only)    |          |   closed   |
   |---+--------------------------------+----------+------------|
   |>> | Factory configured - do not    |   W10    |    N/A     |
   |   | alter                          |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Hard drive port address is     |   W11    |    open    |
   |   | 1F0-1F7h                       |          |            |
   |---+--------------------------------+----------+------------|
   |   | Hard drive port address is     |   W11    |   closed   |
   |   | 170-177h                       |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Floppy drive port address      |   W12    | pins 2 & 3 |
   |   | 3F0-3F7h (8250/8250C/8257      |          |   closed   |
   |   | only)                          |          |            |
   |---+--------------------------------+----------+------------|
   |   | Floppy drive port address      |   W12    | pins 1 & 2 |
   |   | 370-377h (8250/8250C/8257      |          |   closed   |
   |   | only)                          |          |            |
   |---+--------------------------------+----------+------------|
   |>> | Power-ground and               |   W13    |    open    |
   |   | chassis-ground separate        |          |            |
   |---+--------------------------------+----------+------------|
   |   | Power-ground and               |   W13    |   closed   |
   |   | chassis-ground connected       |          |            |
   +------------------------------------------------------------+