On 23/3/22 21:08, ruud_at_Baltissen.org wrote: > But to be honest, I lean more to an even simpler solution: > connecting the SD card directly to the 6522. But I'm sure this will > come with a penalty: speed. IIRC the 1541 collects a byte from the > floppy every 23 uSec. Collecting 8 bits by bit banging and rolling > them into a byte will cost much more time: > - toggle clock bit of SD > - read bit into bit 7 > - roll bit into Carry > - roll Carry into end byte > - toggle clock bit of SD > Rough guess: 17 uSec for one bit? That would be 7KB/s. Not bad. Anyway, a Raspberry Pico is 4€ (the microcontroller, not the Linux computer)... You can read the SD there and send/receive entire bytes to the C64. I think that a Raspberry Pico connected to the read/write heads and the step motor control of a 1541 in order to replace physical diskettes with a SD card (that records flux changes not "bits") could be an interesting project and it would be compatible 100% with fast loaders. It would replace a physical magnetic media wit a "virtual" one. The signals that the 1541 reads/writes would be the same, so 100% compatible. -- Jesús Cea Avión _/_/ _/_/_/ _/_/_/ jcea_at_jcea.es - https://www.jcea.es/ _/_/ _/_/ _/_/ _/_/ _/_/ Twitter: _at_jcea _/_/ _/_/ _/_/_/_/_/ jabber / xmpp:jcea@jabber.org _/_/ _/_/ _/_/ _/_/ _/_/ "Things are not so easy" _/_/ _/_/ _/_/ _/_/ _/_/ _/_/ "My name is Dump, Core Dump" _/_/_/ _/_/_/ _/_/ _/_/ "El amor es poner tu felicidad en la felicidad de otro" - Leibniz
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