Miscellaneous #6
IWM Port Description
Revised by Glenn A. Baxter (November 1988)
Written by Cameron Birse (February 1986)
This Technical Note documents the IWM port pin assignments on various
machines.
Apple IIGS Disk Port Pin Assignments
- Signal Name
- Disk Port Pins (DB-19)
- Phase 0
- 11
- Phase 1
- 12
- Phase 2
- 13
- Phase 3
- 14
- /WReq
- 15
- Dr1
- 17
- Rd
- 18
- Wr
- 19
- Wrt Prot
- 10
- Dr2
- 9
- HeadSel
- 16
- Gnd
- 1,2,3
- 3.5Disk
- 4
- -12v
- 5
- +5v
- 6
- +12v
- 7,8
Apple IIe UniDisk 3.5 Controller Disk Port Pin Assignments
- Signal Name
- Disk Port Pins (DB-19)
- Phase 0
- 11
- Phase 1
- 12
- Phase 2
- 13
- Phase 3
- 14
- /WrtReqII
- 15
- /HstEnbl
- 17
- Rd
- 18
- Wr
- 19
- Wrt Prot
- 10
- No Connection
- 9,16
- Gnd
- 1,2,3,4
- -12v
- 5
- +5v
- 6
- +12v
- 7,8
Apple IIc Disk Port Pin Assignments
- Signal Name
- Disk Port Pins (DB-19)
- Phase 0
- 11
- Phase 1
- 12
- Phase 2
- 13
- Phase 3
- 14
- /WrtReq
- 15
- /Enbl 2
- 17
- Rd
- 18
- Wr
- 19
- Wrt Prot
- 10
- No Connection
- 16
- Gnd
- 1,2,3,4
- -12v
- 5
- +5v
- 6
- +12v
- 7,8
- External Interrupt
- 9
Note: On the Apple IIc Plus, the disk port pins are
driven by a custom ASIC instead of by the IWM chip.
Macintosh Disk Port Pin Assignments
- Signal Name
- Disk Port Pins (DB-19)
- Phase 0
- 11
- Phase 1
- 12
- Phase 2
- 13
- Phase 3
- 14
- /WrtReq
- 15
- /Enbl 2
- 17
- Rd
- 18
- Wr
- 19
- PWM
- 10
- HdSel
- 16
- GND
- 1,2,3,4
- -12v
- 5
- +5v
- 6
- +12v
- 7,8
This and all of the other Apple II Technical Notes have been converted
to HTML by Aaron Heiss as a public service to the Apple II community, with
permission by Apple Computer, Inc. Any and all trademarks, registered and
otherwise, are properties of their owners.