Floppy drive track-0 issues

Philip Pemberton classiccmp at philpem.me.uk
Sat Jan 9 20:06:28 CST 2010


Hi guys,

I've got a Citizen Z1DE-55A (3.5" 1.44MB PC) floppy drive hooked up to 
the disc analyser (it seems my Sony MPF520 has a duff head; it's reading 
garbage for one side of the disc). Here's the problem...

- When the drive is selected, irrespective of head position, TRK00 is 
always inactive.
- If the drive is given a seek command, it will seek to track 0, assert 
TRK00, but the INDEX and READ DATA outputs will go idle (float high).
- The drive remains stuck in this state until power-cycled.

Has anyone seen this kind of thing before? The MPF520 had a head-step 
lockout (if track0_sensor == active, then ignore STEP commands) but 
didn't crash out if you asked it to step.

For what it's worth, the drive works fine in my PC... I just can't see 
why it's locking up like this.

Also, am I right in thinking that pins 12 (DS1) and 16 (MOTEN) are the 
two I need to pull low to select the drive, if it's connected before the 
twist in the cable? And that DS0 and DS2 would be the select and motor 
enable pins (respectively) if the drive was located after the twist?

Citizen are, as always, their usual "helpful" selves: "We don't make 
floppy drives, we never made floppy drives. LA-LA-LA, NOT LISTENING!"

Thanks,
-- 
Phil.
classiccmp at philpem.me.uk
http://www.philpem.me.uk/



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