SCIENTIFIC MICRO SYSTEMS, INC.

OMTI 7250

  Data bus:                   50-pin SCSI interface

  Size:                       5.75" x 8"

  Hard drive supported:       Up to two ST506/412 MFM drives, up to two
                              ST506/412 RLL 2,7 drives, up to two ESDI
                              drives

  Floppy drives supported:    Two 360KB, 720KB, 1.2MB, 1.44MB drives or
                              8"



[Image]

                           CONNECTIONS

                  Function                        Location

  50-pin SCSI interface                              J1

  34-pin ESDI or MFM disk control connector          J2

  20-pin data cable connector                        J3

  20-pin data cable connector                        J4

  34-pin floppy drive connector                      J7

  DC power connector                                 J10

                               SCSI ADDRESS

     SCSI ID              W1                 W2                 W3

  »        0             open               open               open

  »        1            closed              open               open

  »        2             open              closed              open

  »        3            closed             closed              open

  »        4             open               open              closed

  »        5            closed              open              closed

  »        6             open              closed             close

  »        7            closed             closed             closed

                        USER CONFIGURABLE SETTINGS

               Function                    Location           Setting

  »   SCSI parity enabled                     W4               closed

  »   SCSI parity disabled                    W4                open

  »   Factory configured - do not             W5                open
      alter

  »   ST506/412 interface for drive           W6                open
      select 1 enabled

  »   ESDI interface for drive                W6               closed
      select 1 enabled

  »   ST506/412 interface for drive           W7                open
      select 2 enabled

  »   ESDI interface for drive                W7               closed
      select 2 enabled

  »   TRMPWR supplied by board          W14/pins 1 & 2         closed

  »   TRMPWR supplied by SCSI bus       W14/pins 2 & 3         closed

  »   Ready signal from pin 2 to FDC          W15               open
      765 disabled

  »   Ready signal from pin 2 to FDC          W15              closed
      765 enabled

  »   Ready signal from pin 34 to             W16               open
      FDC 765 disabled

  »   Ready signal from pin 34 to             W16              closed
      FDC 765 enabled

  »   Ready override to FDC 765               W17               open
      disabled (Rev. B only)

  »   Ready override to FDC 765               W17              closed
      enabled (Rev. B only)

  »   Motor On signal delay enabled           W18               open

  »   Motor On signal enabled                 W18              closed

  »   Factory configured - do not             W37               open
      alter

  »   Factory configured - do not             W38               open
      alter

  »   Factory configured - do not             W39               open
      alter

       Note: Drive select 1 & 2 refer to the drive select jumper setting
       on the drive itself and should be set to 1 & 2 respectively.

       The location of W39 is unidentified.

                       LUN 0 DISK TYPE CONFIGURATION

             Drive Type                      W9                 W10

  »   ST506/412                             open               open

  »   ESDI                                 closed              open

  »   Removable ST506/412                   open              closed

  »   Flexible disk                        closed             closed

                       LUN 1 DISK TYPE CONFIGURATION

             Drive Type                      W12                W13

  »   ST506/412                             open               open

  »   ESDI                                 closed              open

  »   Removable ST506/412                   open              closed

  »   Flexible disk                        closed             closed

                      LUN 0/1 FLEXIBLE DISK DATA RATE

            Data Rate                  W8(Lun 0)           W11(Lun 1)

  »   250 Kbit                           open                 open

  »   500 Kbit                          closed               closed

  Note: These settings apply only when W9 & W10 are both closed.

                     LUN 0/1 SECTOR TYPE CONFIGURATION

               Mode                     W8(Lun 0)          W11(Lun 1)

  »   Soft sector enabled                  open               open

  »   Hard sector enabled                 closed             closed

  Note: These settings apply only when drive type is set to ST506/412.