Ensoniq EPS16 is Generic Shugart?

HxC Floppy Emulator Ensoniq Keyboards/Samplers support
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Ensoniq EPS16 is Generic Shugart?

Post by mondo1976 » Thu Apr 06, 2017 4:49 am

This isn't really an HxC problem, per se, but I'm definitely curious about something and I was hoping there was a floppy interface guru (Jeff or otherwise) that might be able to clarify a point for me.

My understanding is that the HxC works with the EPS16+ using a standard Shugart signal pinout. This definitely seems to be the case because my EPS16+ works properly when so configured. My confusion is that the EPS16+ appears to also rely on another signal besides the ready signal to detect disk changes. I've seen documentation that pin 2 of the EPS16+ is supposed to be diskchange (instead of density select as per Shugart) yet the EPS16+ doesn't function properly when hooking up a real floppy drive which is jumped for ready signal alone, or even ready signal on pin 34 and diskchange on pin 2. The EPS seems to expect some kind of diskchange signal grounding, head seek, flag clearing, or something before it properly recognizes a disk change aside from a traditional ready signal.

Even with the most configurable TEAC drives with 4 rows of jumpers I've never found a way to get the EPS16 to work with a non-OEM drive. I can get it to function by using ready on pin 34, nothing on pin 2, and then manually going to "CHANGE STORAGE DEVICE" and selecting "FLOPPY" in the EPS16 system menu to trigger the detection of disk change. Contrary to the documentation I've seen, disk change on pin 2 only leaves the EPS more confused, yet relying on ready alone doesn't yield proper behavior either.

Just what is the Ensoniq EPS16+ really expecting to see for signals? Are most floppy drives giving some faux-ready signal that the EPS can't handle? Is the Generic Shugart profile modified in some way to handle this fringe case but also work properly with other devices? Just what the heck is going on in this machine? It's the most quirky machine I've ever seen when it comes to floppy drive replacement, as opposed to the very accommodating Mirage which will happily take pretty much anything that isn't a PC drive.

Also, in the HxC software under Custom Interface, what is the difference between diskchange 1, diskchange 2, ready 1, ready 2, nReady, nDiskchange, and so forth?

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