Apple II Technical Notes _____________________________________________________________________________ Developer Technical Support Apple II 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