Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site intelca.UUCP Path: utzoo!watmath!clyde!floyd!harpo!seismo!hao!hplabs!intelca!glen From: glen@intelca.UUCP (Glen Shires) Newsgroups: net.micro Subject: Re: 80-track drives for free? Message-ID: <232@intelca.UUCP> Date: Tue, 20-Mar-84 15:23:50 EST Article-I.D.: intelca.232 Posted: Tue Mar 20 15:23:50 1984 Date-Received: Thu, 22-Mar-84 01:17:25 EST References: <17662@sri-arpa.UUCP> Organization: Intel, Santa Clara, Ca. Lines: 26 >> HOW DO YOU CONTROL THE HALF-STEPPING ON THE APPLE II DISK DRIVE? Briefly, It has four phases controlled by: C080 = stepper motor phase 0 off C081 = stepper motor phase 0 on C082 = 1 off C083 = 1 on C084 = 2 off C085 = 2 on C086 = 3 off C087 = 3 on Timing is very critical, I suggest you adapt the DOS routines at: B9A0-B9FF SEEKABS routine BA00-BA10 Delay routine BA11-BA28 Delay table A good discussion of the Apple ][ disk (including stepping motor) is in: "Beneath Apple Dos", Don Worth and Pieter Lechner ^ ^ Glen Shires, Intel, Santa Clara, Ca. O O {pur-ee,hplabs,ucbvax!amd70}!intelca!glen > \-/ --- stay mellow