Re: Is fast stepping used in the 1541?

From: Greg King (
Date: 2008-10-14 18:00:14

From: ruud.baltissen; on Thursday, July 31, 2008; 05:42 AM -0400
> The next delay is the one for stepping the head.  As I don't use any head-
> stepping at all, I simply removed all routines.  But, Gideon's 'floppy
> drive' does act on the state of the outputs of the 6522; and so, I need at
> least the routines that output the signals for the stepping motor.
> There is a routine for fast-stepping the head and one for slow-stepping.
> The actual decision is made at $FA0E where the number of steps is
> compared with MINSTP ($0064).  MINSTP is filled with the value $C8 = 200
> at position $F2A4.  Whatever the original input is, at $FA0E, register A
> is a number where bit 7 _always_ = zero.  And therefore, A never can be
> greater then $C8; and thus, the fast-stepping routine never is executed.
> Or, am I wrong?

My reply is months late; but, I must ask:

Doesn't 200 steps move the head by 100 tracks?  Why would that code be on
machines that have less than 100 tracks?

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