reading floppy disk data part 6, MFM sector decoding
we fixed some track seeking code errors we had, and now we’re able to start getting data from greaseweazle. since the diskette we’ve got is an ibm pc 1.44MB format we can use the built in ibm pc MFM format decoding module. the good news is that its able to decode *some* tracks…but its not able to decode all of them, like it’ll read 10 good sectors in a row, then just cant find any sectors at all – which is a little suspicious. makes us wonder if we got the flux transfer and index pulse encoding right, or if its a formatting thing, because the diskette is readable on a computer with a usb drive connected – video.
Adafruit Floppy is a project to make a flexible, full-stack, open source hardware/software device for reading, archiving, accessing and duplicating floppy disk media. It joins a family of open source hardware and software such as greaseweazle and fluxengine, and will attempt to increase the availability and accessibility of floppy disk controllers by: porting the greaseweazle / fluxengine firmware to Arduino so that it is less tied to specific hardware, adding firmware support for the RP2040 chip / low cost pico, adding hardware support for reading apple ii disks including index sensing, adding woz/a2r support to greaseweazle / fluxengine, and investigating analog flux data acquisition methods for repair of damaged disks. all of this with permissively licensed hardware and software so folks can re-create without licensing agreements, NDAs, or discussion.
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