bluejay Posted March 19, 2021 Share Posted March 19, 2021 I was enlightened of the reason why Commodore drives are so slow; buggy shift registers in the 6522s. Granted, I don't have an incredibly precise understanding on how the kernal handles the disk drive and vice versa, but wouldn't it be possible to hook up an 8 bit shift register to the data bus on both the computer and drive to make things a whole lot faster? If it is indeed possible, would it be incompatible with existing formats and media? Quote Link to comment Share on other sites More sharing options...
bluejay Posted March 19, 2021 Author Share Posted March 19, 2021 To clarify, from what I understand Commodore decided the shift registers in the 6522s didn’t work so they decided to control everything in software which made things extremely slow. So, perhaps a cartridge that contains a shift register and the serial port, and an internal modification to the floppy drive that contains another shift register along with perhaps some RAM plus a bunch of programming would result in a fast floppy interface for Commodore computers. Quote Link to comment Share on other sites More sharing options...
brain Posted March 19, 2021 Share Posted March 19, 2021 A real shift register is in the 1571/1581 drives. The C128 and those drives call its use "burst mode". FOr the 64, you can use the existing shift register in the 64 to enable the same thing: https://a1bert.kapsi.fi/Dev/burst/ 2 Quote Link to comment Share on other sites More sharing options...
bluejay Posted March 20, 2021 Author Share Posted March 20, 2021 I was thinking of something in the form of a cartridge that would have a shift register that would plug into a modified 1541 to provide that burst mode speed on a C64. If that hardware was made to be compatible with the existing Commodore disk format then I assume it would be a nice little gadget. Quote Link to comment Share on other sites More sharing options...
Tuxon86 Posted March 20, 2021 Share Posted March 20, 2021 7 hours ago, bluejay said: I was thinking of something in the form of a cartridge that would have a shift register that would plug into a modified 1541 to provide that burst mode speed on a C64. If that hardware was made to be compatible with the existing Commodore disk format then I assume it would be a nice little gadget. Like a fast load cart? Quote Link to comment Share on other sites More sharing options...
bluejay Posted March 20, 2021 Author Share Posted March 20, 2021 2 hours ago, Tuxon86 said: Like a fast load cart? A fast load cart is simply a bit of code that replaces the standard c64 floppy drive controlling routines. It is handy but it has its limitations... a really fast hardware shift register would make things a whole lot faster. Quote Link to comment Share on other sites More sharing options...
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