El 28/03/2022 a las 16:27, Gerrit Heitsch escribió: > On 3/28/22 16:34, tokafondo wrote: >> >> > Claudio Sánchez - Tokafondo wrote on 28.03.2022 14:39: >> > >> >> As part of some case mods I'm doing for fun, I've found that the CBM disk drives designed to be used in a standard C64 are all external. >> >> But both the SX64 and the C128D have internal drives. >> >> What would be the least engineered way to have a CBM disk drive connected to a C64 case? >> >> I'm talking about something that would keep the ability to use external drives or printers or whatever. >> >> Maybe a sort of middle PCB that would sit on the CIA 2 socket, and below the 6526 chip itself? >> > >> > Do you need to connect an existing drive (like 1541)? Or do you want to create a completely new drive, perhaps in the style of C65's internal dumb drive or CBM-II's planned low cost disk drive? >> >> It's still a sort of "remix" of existing technologies. Taking internals out of drives and putting them in a modded case with the C64. >> >> > >> > For connecting a 1541, yes you can create a PCB to piggyback on the CIA socket but not all C64's have socketed CIAs. >> >> I was wondering if is there anyway to take the serial protocol out of the communication between a C64 and a "not dumb" CBM drive and make both talk about DMA. >> >> There is a CBM drive already doing that, isn't it? One for the PLUS4 series, I think... > > No, not using DMA, just a different I/O-port. That adapter you plug into the plus/4 contains a PLA (251641-03) and a 6523T (6525 in 28pin). There is no DMA involved. Thanks. What about taking the serial protocol out? I mean: AFAIK, all data transfers in the serial bus are I/O based: the computer CPU writes or read data into a specific memory address so the CIA makes its job of sending it to, or receiving it from the drive, isn't it? And the CBM drive CPU does the same: read or write data in its companion CIA memory location for the same reason. So why not to get rid of the CIAs and make both CPUs to access the same memory location inside the computer, via DMA? > > Gerrit > >Received on 2022-03-30 14:00:02
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