Floppy Interfacing Hack Chat with Adafruit

Floppies and CircuitPython, together at last

Wednesday, February 2, 2022 12:00 pm PST Local time zone:
Hack Chat
Similar projects worth following

Adafruit's Limor "Ladyada" Fried, Jeff Epler, and Phillip Torrone will host the Hack Chat on Wednesday, February 2 at noon Pacific.

Time zones got you down? Try our handy time zone converter.


When a tiny fleck of plastic-covered silicon can provide enough capacity to store a fair percentage of humanity's collected knowledge, it may seem like a waste of time to be fooling around with archaic storage technology like floppy disks. With several orders of magnitude less storage capacity than something like even the cheapest SD card or thumb drive, and access speeds that clock in somewhere between cold molasses and horse and buggy, floppy drives really don't seem like they have any place on the modern hacker's bench.

Or do they? Learning the ins and out of interfacing floppy drives with modern microcontrollers is at least an exercise in hardware hacking that can pay dividends in other projects. A floppy drive is, after all, a pretty complex little device, filled with electromechanical goodies that need to be controlled in a microcontroller environment. And teasing data from a stream of magnetic flux changes ends up needing some neat hacks that might just serve you well down the line.

So don't dismiss the humble floppy drive as a source for hacking possibilities. The folks at Adafruit sure haven't, as they've been working diligently to get native floppy disk support built right into CircuitPython. To walk us through how they got where they are now, Ladyada, Jeff, and PT will drop by the Hack Chat. Be sure to come with your burning questions on flux transitions, MFM decoding, interface timing issues, and other arcana of spinning rust drives.

  • Hack Chat Transcript, Part 2

    Dan Maloney02/02/2022 at 20:49 0 comments

    Will S Merkens12:36 PM
    I have stuff stored on 8mm tape and it's still readable

    Nick Tonn12:36 PM
    Well, i still disagree about the theory that drives are made specific for MFM and fail at GCR.

    PixelDud12:36 PM
    @deʃhipu My guess, SSDs.

    Tom Nardi12:36 PM
    @deʃhipu Good point, I've had CD-R and DVD-R discs both become unreadable after a few years. Though their are supposedly "archival" burnable discs"

    brainsmoke12:37 PM
    keep your ssds powered

    deʃhipu12:37 PM
    clay tablets last for thousands of years

    Tom Nardi12:37 PM
    Just don't drop them.

    deʃhipu12:37 PM
    progress, I suppose

    Jeff Epler12:37 PM
    I think the best thing to do is use any kind of media you keep "live" in your computer, and making sure there are two copies e.g., through mirrored disks, online backups, etc. Data that's not live is data that may be dead

    DrG12:38 PM
    I have also found 30 year old commodore disks still working fine...and I was amazed...probably 98/100. I have not had as good a record with home made CD/RW

    Tom Nardi12:38 PM
    @Jeff Epler Well said.

    deʃhipu12:39 PM
    @Jeff Epler also verify your backups

    Will S Merkens12:39 PM
    by the end of cdr era the media tend to use poor dye layer but if you have cdr's from the 1980's like I do they used a metallic layer and I can still read them perfectly.

    Vincent12:39 PM
    But all live data will only be good until SkyNet... 😆

    Jeff Epler12:40 PM


    Reading Floppies With An Oscilloscope

    There's a lot of data on magnetic media that will soon be lost forever, as floppies weren't really made to sit in attics and basements for decades and still work. [Chris Evans] and [Phil Pemberton] needed to read some disks that reportedly contained source code for several BBC Micro games, including Repton 3.

    Read this on Hackaday

    pt12:40 PM

    pt12:40 PM
    we're going to bounce now (back to engineering / making / shipping electronics)

    Chris12:40 PM
    Imagine the oscilloscope data we can now read with MCU! There are still floppy-enabled measurement equipment at the company I'm working at.

    Dan Maloney12:41 PM
    Thanks everyone! Looking forward to more floppy progress!

    Jeff Epler12:41 PM
    on the live broadcast we're going to close out with some visual stuff, so jump over to the video if you can

    Dan Maloney12:41 PM
    Looks like a washing machine motor

    deʃhipu12:42 PM
    it doubles as a washing machine

    deʃhipu12:42 PM
    they don't make them like they used to anymore

    hamslabs12:43 PM
    What is the processor on that board?

    limor12:43 PM
    on the 8" drive? all Shugart chips :)

    pt12:44 PM
    we'll be posting all the progress across the socialz and more !

    Will S Merkens12:44 PM
    what is the model of the sony floppy you are using

    Jeff Epler12:44 PM
    @Will S Merkens I have a Sony MFP520-1

    Vincent12:44 PM
    I'm so sad I threw all my old floppies from my parent's house, including many beautifully translucent-neon ones 🥺

    limor12:44 PM
    Sony MFP920 but we think any sony MFP can do GCR

    Will S Merkens12:44 PM

    Nick Tonn12:44 PM
    The commodore floppy had its own 6502 which was clocked faster than the one in the c64 :)

    hamslabs12:44 PM
    Thanks y'all.

    deʃhipu12:44 PM
    thank you

    Ferdinand Vogeler12:45 PM
    nice one thanks

    limor12:45 PM
    woo hoo

    Jeff Epler12:45 PM
    See y'all next hack chat!

    Dan Maloney12:45 PM
    Thanks Adafruit! Thanks everyone -- transcript coming!

    limor12:45 PM
    thanks everyone :)

    Dan Maloney12:45 PM
    And next week:

    Dan Maloney12:45 PM


    Pick and Place Hack Chat

    Chris Denney will host the Hack Chat on Wednesday, February 9 at noon Pacific. Time zones got you down? Try our handy time zone converter. We in the hacker trade are pretty used to miracles -- we make them all the time.

    Read this on Hackaday

    DrG12:45 PM
    Thanks for hosting Dan

    limor12:47 PM
    more on GCR/MFM floppy analysis

  • Hack Chat Transcript, Part 1

    Dan Maloney02/02/2022 at 20:48 0 comments

    Dan Maloney12:00 PM
    Let's get started everyone. Welcome to the Hack Chat, please pardon my typing -- sprained my finger yesterday. I'm Dan, I'll be modding today along with Dusan as we welcome Adafruit for their first Hack Chat of 2022!

    pt12:00 PM


    Dan Maloney12:01 PM
    We've got a livestream setup on YT - there it is ^^^

    limor12:01 PM

    Dan Maloney12:02 PM
    So the setup is to ask questions here, and they'll answer over on the live stream, plus they'll text answers here too

    Dan Maloney12:02 PM
    A multimedia extravaganza!

    Dusan Petrovic12:02 PM

    limor12:02 PM
    hi its ladyada! if you can't get parts, why not get ones that are no longer even made anymore! so ... retro tech :)

    limor12:03 PM
    floppy disks! both simpler and more complicated than you may think

    Dan Maloney12:03 PM
    Can you even find floppies in e-waste anymore?

    Frank Palazzolo joined  the room.12:03 PM

    limor12:03 PM
    a LOT of floppy disks were manufactured

    deʃhipu12:03 PM
    there is nothing electric about floppiesw

    Jeff Epler12:03 PM
    Hi! I'm Jeff, and I work with Adafruit mostly on CircuitPython. Limor pulled me into this floppy project, and I'm having a blast getting back into the retro computing aspect of it.

    Yannick (Gigawipf)12:03 PM
    More likely than getting new microcontrollers @Dan Maloney

    limor12:03 PM
    and computers pretty quickly removed floppy drives, i think the market was a little 'shocked'

    Dan Maloney12:03 PM
    Sorry -- floppy drives

    limor12:04 PM
    yes often folks who toss our computers have delicious floppy drives in there

    limor12:04 PM
    rescue them :)

    Jeff Epler12:04 PM
    PT gets the best stuff like signed "hackers" floppies

    Yannick (Gigawipf)12:04 PM
    But getting more rare. I am currently on the search for (a lot of) drives and it is getting harder to get them.

    landerosmaster joined  the room.12:04 PM

    pt12:05 PM
    goodwill, flea markets, and ebay are pretty good

    Yannick (Gigawipf)12:05 PM
    Some time ago you could get them anywhere computers were replaces. Schools mainly. But now known good drives can get quite expensive

    deʃhipu12:06 PM
    try to get an usb floppy drive

    Mark Morgan Lloyd12:06 PM
    Extracted a drive from an old system the other day, but it's getting increasingly difficult to know that they're in alignment. I remember there was a Hackaday article discussing a Yamaha Disklavier with its floppy out of alignment.

    limor12:06 PM
    a looooooooot of disk drives were made. they are out there

    Evan Allen12:06 PM
    I'm doing stuff with vintage media that's a little more esoteric. Hard sectored 5.25" and 8" drives are my focus right now. Looking to image disks and emulate the drives.

    pt12:06 PM
    why don't usb floppy drives always work? limor is answering ...

    Jeff Epler12:07 PM
    Limor's showing on the stream what's in a USB floppy

    pt12:07 PM
    for example, the prince floppy can't be read with a USB floppy drive (mac)

    Jeff Epler12:07 PM

    Jeff Epler12:07 PM
    There's a laptop floppy drive + a USB controller (no name, no datasheet)

    landerosmaster12:08 PM
    What I'm using is an old compaq 34 pin floppy drive

    Jeff Epler12:08 PM
    the connector is a (semi) standard, the folks who make usb floppy drives get standard laptop floppies and repackage them with the controller

    Jeff Epler12:08 PM
    it only works with 1.44MB and only for IBM format floppies in MFM format

    Jeff Epler12:08 PM
    You couldn't, for instance, read a Mac 800kB mac "GCR" floppy disk

    Nick Tonn12:08 PM
    The slim drives in the usb ones are quite noisy and inferior to the full size drives, also the flex cable connector isn't easy to interface for diy.

    Jeff Epler12:08 PM
    if you remove the extra board, you can hook into the USB floppy disk with your own controller, like what we've been working on

    Jeff Epler12:09 PM
    (or boards like greaseweazel if you can get 'em)

    Adam Katalak joined  the room.12:09 PM

    Jeff Epler12:09 PM
    Limor has found that the floppy controller can be flaky, and it's not good...

    Read more »

View all 2 event logs

Enjoy this event?



Interested in attending?

Become a member to follow this event or host your own