Reference of first flux transition

[AlWe]

The SuperCard Pro uses a hardware interrupt to start the capture and that comes from the index pulse.  The index to index time and total number of bitcells comes from the drive. 

Let's stick to single-revolution images for now.
The main issue I have is, that when I add all flux times of one revolution together I can get a bigger value then what the header has for index2index. Not always but still quite often... At least 1/3rd of all tracks, based on my very small sample size of three images so far. (I also see that in an amiga scp image but there I only checked track 0.)

With your confirmation that the first flux bitcell is relative to the index that would then probably mean that it's not stopping exactly at the next index pulse but can add some flux transitions after the index at the end to a track. But that would then be up to maybe 3ms and definitely > 100 25ns ticks...

In that case I can simply drop the bitcells which would be located behind the 2nd index pulse and directly jump back to the first flux of the track and figure out what the real flux2flux interval would have been without the Index.

Maybe a simple ASCII of how that could look like:

Code:

INDEX
1st flux (ticks since INDEX)
2nd flux (ticks since last flux)
...
last real flux of track
INDEX                   
flux (probably ticks since last flux instead of INDEX)
last flux recorded for TRK

To get the time between the last real flux and the index I would have to add flux times together until it gets bigger than the index2index time, remove the last addition again and then subtract the accumulated time from the index2index time to get the time between the last real flux on the track and the 2nd INDEX.
Would be a bit unexpected but trivial to handle...

I'm using a Panasonic Matsushita JU-257A604P 1,44MB Floppy Disk Drive, powered via the supercard.
My test disks images for that are the disk 1 from Novel Dos 7 and a Copy of MS Dos 6.2. (Both images can be decoded without any error.)