'morning, I've found numerous articles discussing how to emulate a floppy disk DRIVE, here and elsewehere and there even seem to exist commerial solutions. Yesterday I revived an old SB180FX (HD64180 CPU with a CP/M compatible OS) and had been contemplating beforehand what to do if the floppy drives or the disks failed. I was wondering if it were possible to replace the floppy controller (FDC9266) by a microcontroller that emulated the FDC (register read/write, DMA) and stored the data blocks on an SD card or such (anyone know if SD cards with 1.44MB capacity exist? ;-) ). I would read/write the raw data on my PC, so the controller would just map the floppy's blocks 1:1 to the SD card or even map all four drives to separate sections on the SD card. The bus speed to the processor (running a ~12MHz) would need some attention, maybe adding hardware support in the form of a flipflop which generates WAIT cycles (within reasonable limits) by being set automatically by any access and which is then reset by the microcontroller. This only affects the reading/writing of commands and status, after that the microcontroller would work internally transferring data via (emulated) DMA. I'd prefer an ATmega of sorts. Question: has anyone done this before? Josef
Using a floppy drive emulator is all nice and well if you have a floppy controller to attach your drive emulator to. Unfortunately the FDC9266 I had has turned out not to bee 12V-resistant :-( I have ordered a few 9268s from Mr. Chinaman but the order is still pending. In the event of non-delivery, I will have to dig up something that is able to replace the 9266. So, unless someone has a 9266 (or 9268) that (s)he wants to part from, I'll try to emulate the controller. Josef PS Getting the data off the original disk(s) is another problem: 1024 Bps, 5spt ... Maybe I can convince the Linux floppy.c driver to read the disk(s).
Josef M. wrote: > PS Getting the data off the original disk(s) is another problem: 1024 > Bps, 5spt ... Maybe I can convince the Linux floppy.c driver to read the > disk(s). This drive might be a solution: "TEAC FD-235HS 1111 SCSI Drive": According to the datasheet it can, indeed, read 1024 Bps.
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