Recent content by Arbee

The only 68k Macs with DMA SCSI under Mac OS are the Quadra AVs. (IIfx has hardware for it but only A/UX uses it).

Dingus is not on Homebrew, but it's really easy to compile on macOS.

Floppy is pretty standard if you have SWIM1 implemented. The ROM will detect it and work if you substitute an IWM and an 800k drive, as well, and since the LC can boot System 6 it's even feasible to boot that way. SCSI is the same as every other Mac with a 5380 since the Plus, including the...

LC's not the easiest to get going but far from the hardest. The early hang-ups are: 1) Egret (the 68HC05 microcontroller) has to exist or you probably won't chime 2) The memory sizing routine will get angry in a hurry if the V8 bank sizing registers don't do what they're supposed to 3) The...

Just for reference, it won't normally drop into STM unless PA0 tells it to. So if you weren't intending it to do that, now you know why. As far as commands, mac68k.info is currently down, but this Wayback Machine link should work...

Are you intending it to go into STM TechStep mode or is the problem that it's going into that instead of booting? That's controlled by bit 0 of VIA port A, 1 = normal boot, 0 = STM.

I boot and run the Quadra/LC 630 in MAME by treating PrimeTime II as a slightly different IOSB. The differences are mostly centered around the ATA controller being added and that changes how interrupts work a bit. The SCSI thing is this: on reads, Apple does an unrolled loop of MOVE.L from the...

PrimeTime and PrimeTime II are essentially re-spins of IOSB. The fun part of all of those chipsets is that they expect to be able to halt processor bus read/write bus transactions indefinitely while the SCSI bus catches up. That's a serious pain for emulation, although it's probably a lot...

Marginal traces can let go just from the machine being used (probably due to thermal expansion/contraction). It's why getting a restored machine to boot is never the end.

https://wiki.mamedev.org/index.php?title=Driver:Mac_68K:Tech_Info:ASICs has basically everything anyone knows about Apple 34x numbers. But yes, 344S0061 is SWIM1 and 343S0137 is the somewhat rare discrete SWIM III (it's built into the system ASIC on almost everything that used it).

I know a fair amount about the LC given MAME emulates it register-level throughout and supports PDS cards. What do you need to know beyond what's in the developer note?

I've been highly skeptical of AI (and generally remain so), but the recent model versions (like in the last 3-6 months) have been a significant improvement. The Apple II guys recently got Claude to convert the Orca/C compiler for the Apple IIgs from Pascal to ANSI C. (Yes, the official C...

Regarding sync and interrupts: the Mac OS wants a VBlank IRQ from each video card, which it uses to update the mouse pointer "flicker free" when it's on that card's framebuffer. If a card doesn't have an IRQ, the pointer will freeze and not move forever when it goes onto that monitor. (The...

Claude's getting pretty impressive. Orca/C for the Apple IIgs, the official on-device compiler, has been source-available for a while now, but it's written entirely in Pascal (because that compiler already existed when they started on C). Claude successfully converted it into 100% C that...

The neck connector is keyed, so the neckboard would also rotate 180 degrees. That might require extending the leads to it. To put the picture back to normal, you'd have to either rotate the yoke 180 degrees so it's back to it's original orientation (but 180 degrees from the now-rotated CRT) or...