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"

   

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 alter

W5

open

»

ST506/412 interface for drive select 1 enabled

W6

open

»

ESDI interface for drive select 1 enabled

W6

closed

»

ST506/412 interface for drive select 2 enabled

W7

open

»

ESDI interface for drive select 2 enabled

W7

closed

»

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 765 disabled

W15

open

»

Ready signal from pin 2 to FDC 765 enabled

W15

closed

»

Ready signal from pin 34 to FDC 765 disabled

W16

open

»

Ready signal from pin 34 to FDC 765 enabled

W16

closed

»

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

W17

open

»

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

W17

closed

»

Motor On signal delay enabled

W18

open

»

Motor On signal enabled

W18

closed

»

Factory configured - do not alter

W37

open

»

Factory configured - do not alter

W38

open

»

Factory configured - do not alter

W39

open

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.

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