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, 1.44MB
Sector interleave: 1:1
Maximum heads/cyl.: 16 heads and 2048 cylinders
CABLE CONNECTIONS | |
34-pin data cable connector-floppy drive (OMTI 8250/C/8257 only) | J1 |
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 |
Function | Location | Setting | |
» | Sysclk signal from AT bus input to 5098C chip | W7 | pins 1 & 2 closed |
No sysclk signal from bus, input tied low | W7 | pins 2 & 3 closed | |
» | Single speed floppy drives (OMTI 8250/8250C/8257 only) | W8 | pins 1 & 2 closed |
Dual speed floppy drives (OMTI 8250/8250C/8257 only) | W8 | pins 2 & 3 closed | |
» | Floppy precomp. values normal (8250/8250C/8257 only) | W9 | pins 2 & 3 closed |
Alt. floppy precomp. values (OMTI 8250/8250C/8257 only) | W9 | pins 1 & 2 closed | |
» | Factory configured - do not alter | W10 | N/A |
» | Hard drive port address is 1F0-1F7h | W11 | open |
Hard drive port address is 170-177h | W11 | closed | |
» | Floppy drive port address 3F0-3F7h (8250/8250C/8257 only) | W12 | pins 2 & 3 closed |
Floppy drive port address 370-377h (8250/8250C/8257 only) | W12 | pins 1 & 2 closed | |
» | Power-ground and chassis-ground separate | W13 | open |
Power-ground and chassis-ground connected | W13 | closed |