Quote:
Originally Posted by Gorf
wouldn't this be double (25 KB) because of the MFM encoding?
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Paula transfer RAW bitstream with speed of 500kbps (for 250kbps MFM), floppy spin 300 revolution per second, simple math - 300/60=5 revolution per second i.e. single revolution per 200ms, if RAW bitstream transfer is 500kbps (in real case this is 507kbps for PAL and 511kbps for NTSC) then in 200ms you can write 101.4kb for PAL and 102.2kb for NTSC i.e. 12.675KB for PAL or 12.775KB for NTSC. This is more or less inline with RAW 3.5 inch floppy RAW capacity (2MB)
Quote:
Originally Posted by Gorf
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I would left SPI and boot ROM intact as easily USB host can be used to serve thumbdrives and side to this easily SD flash card can be interfaced to RP2040 thanks to PIO machine. Of course we could use serial NAND flash (as NOR is rather expensive for storing data) but i bet than using USB or SD (other types serial cards) will be simply cheaper than soldering NAND IC.
Still most interesting for me is MC68000 emulation on RP2040 - or
https://github.com/kstenerud/Musashi or perhaps
https://github.com/notaz/cyclone68000 - using simple TTL logic to convert levels and at the same time interface PIO with MC68000 bus should open possibility to emulate for example fast MC68020 (richest instruction set) with decent clock some cache and at a cost of few $.