Author Topic: Random talk about old floppy drives.  (Read 951 times)

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Offline glarsson

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Random talk about old floppy drives.
« on: June 28, 2018, 07:20:59 pm »
Discussion continued from here: https://www.eevblog.com/forum/chat/what-did-you-buy-today-post-your-latest-purchase!/msg1636547/#msg1636547

That's a neat idea.  I guess you tied into the head load control line?
No. I designed both the hardware and the software. The starting of the spindle was done in the software (CP/M BIOS) with waiting until the floppy was up to speed. The hardware was built around the 1793 chipset (later 2793) with my own additions on the side for extra features and fixes for software bugs in the 2793. Some form of hardware timer shut down the spindle after a while. It was 37 years ago, so the exact details are a bit fuzzy.
You're talking software, right?  The controller side determines the step rate.  I would think that you might have to tune that on a drive by drive basis.
Software and I/O-pins on the floppy controller board. The tables could be tuned per drive. Originally full height Shugart 8 inch drives, but later upgraded to half height Shugart 8 inch drive (with 24V motor for the spindle) and 1.6MB 5.25 inch floppy. My BIOS could auto detect formats, so I supported the common ones plus my own format giving 1.6MB for the 80 track formats. All boards were my own design with nice features like a 7.3MHz Z80, MMU, 128K fast static RAM, and interrupt driven CP/M BIOS (requires patch to BDOS).
 


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