Subject: Re: Pinout for Disk II and IIc/IIc plus disk ports Newsgroups: comp.sys.apple2 From: dempson@actrix.gen.nz (David Empson) Date: Wed, 19 Jul 2000 00:53:55 +1200 Message-ID: <1edzqzz.p7bkjs1ahfkzkN%dempson@actrix.gen.nz> References: <8kol57$fja$1@nnrp1.deja.com> Organization: Empsoft User-Agent: MacSOUP/2.4.2 NNTP-Posting-Host: 202.49.157.176 X-Original-NNTP-Posting-Host: 202.49.157.176 X-Trace: 19 Jul 2000 01:33:34 NZST, 202.49.157.176 Lines: 88 Path: lobby!newstf02.news.aol.com!portc01.blue.aol.com!newsfeed.direct.ca!look.ca!usenet.net.nz!news.iprolink.co.nz!news.actrix.gen.nz!dempson Frank Townsend wrote: > While looking for a DB19 M/F cable, I found the following which sounds like > what you're looking for. > > http://ground.ecn.uiowa.edu/apple2/MiscInfo/IIc/prout > > It's apparently all from the Apple TIL: > > External Floppy Drive Connector > ------------------------------- > > The Apple IIc external disk drive port is a DB-19 connector. The signals > available at the port are as follows: > > 10 - WRPROT > 1 - GND > 11 - SEEKPH0 > 2 - GND > 12 - SEEKPH1 > 3 - GND > 13 - SEEKPH2 > 4 - GND > 14 - SEEKPH3 > 5 - +12V > 15 - /WRREQ > 6 - + 5V > 16 - NC > 7 - +12V > 17 - /DR2 > 8 - +12V > 18 - RDDATA > 9 - /EXTINT > 19 - WRDATA Whoa! Pin 5 is -12V, not +12V. Pin 17 is normally drive 1 enable. This happens to enable drive 2 for the IIc, since it already has an internal 5.25" drive. This signal is actually the enable line for the first connected 5.25" drive. Note that /EXTINT (pin 9) is unique to the Apple IIc. For all other implementations of this connector, pin 2 is drive 2 enable. The first UniDisk 5.25 or Apple 5.25 Drive will redirect this signal to pin 17 of its daisy-chain connector, so that both drives use pin 17 to select them. (Everything works differently for a 3.5" drive, with different rules for the Apple 3.5 Drive and SmartPort devices like the UniDisk 3.5.) Here is a full list of the signals for the three types of 5.25" drive, courtesy of Open-Apple volume 1 number 11. Signal Uni-DuoDisk IIc external Disk ][ GND Ground Reference 1-4 1-4 1,3,5,7 -12 -12 volts DC 5 5 9 +5 +5 volts DC 6,16 6 11,12 +12 +12 volts DC 7-8 7-8 13,15,17,19 WRPROT write protect 10 10 20 PH0-3 stepper motor phases 11-14 11-14 2,4,6,8 WRREQ write request 15 15 10 ENBL drive enable 17,(9) 17 14 RDDATA read data 18 18 16 WRDATA write data 19 19 18 EXTINT external interrupt n/a 9 n/a not connected n/a 16 n/a The Disk ][ controller has separate connectors for each drive, and the two connectors have identical signals, except for pin 14, which comes from the appropriate drive enable line. If you want to build an adaptor from the IDC-20 used with the Disk ][ to the D-19 used on later drives, it is _almost_ a straight ribbon cable connection, using a ribbon cable mounting D-19. The exceptions are: D-19 pin 9 should go to pin 14 for drive 2 (it would normally go to pin 17 on the IDC-20 if you use a direct ribbon cable connection). D-19 pin 10 should go to pin 20 on the IDC-20 (it would normally go to pin 19 on the IDC-20). IDC-20 pins 17 and 19 should not be connected. -- David Empson dempson@actrix.gen.nz Snail mail: P O Box 27-103, Wellington, New Zealand