Recent content by Arbee

I think I've mentioned this before, but these Lapis cards are wild - they reconfigure the FPGA in order to switch modes and color depths.

Good find on the Duo 210/230 schematic, whoever dug that up! The details I've checked all look final to me. As the schematic indicates, panel IDs for GSC and CSC are read from the actual panel and are different per machine, unlike the monitor IDs in desktop Macs. Each machine only recognizes...

It's not remotely MDA/*GA compatible so I would expect it to turn up in non-PC laptops only.

It's listed as a standard part in one of their databooks, but I've only seen Apple use it.

GSC is a relabeled Chips & Technologies 65210, incidentally. Unfortunately no datasheets seem to exist online, although the System 7.1 source tree at least has register descriptions.

Vintage TV restorers have come up with ways to fix that (it's possible to use heat to separate the lens from the CRT and remove the glue) but as you note it's not easy and can be a bit dangerous.

The power key is both a key readable through the microcontroller and a directly connected switch with a dedicated pin on the ADB connector. So it's possible for it to turn the machine on even if the microcontroller is dead or missing. That said, clearly it's not dead since it works on the...

The keyboard works 100% on the SE/30, but on the Q700 only the power key works? That's really strange.

@powermax I don't have anything on DFAC-II beyond looking at how it's connected in some of the schematics and logging what gets written to it over I2C. I have a ton of info on original DFAC, but DFAC-II seems to be pretty different aside from having the same overall function (input selection...

For clarification, the Macintosh TV is not a 5xx, it's LC II/Color Classic architecture in a 5xx case.

There are ERSes for ASC and EASC but they're much less helpful than you'd think, which is why ASCTester is necessary. Prior to the test program most of what I knew about them was from staring at IDA Pro.

Interesting. On the Q630/LC580 (and the Q800 and Q605 generations) the startup bong is normal and System 7.1 acts completely normally, but 7.5.3+ force the 16-bit path, and the intended behavior there doesn't completely make sense yet. There's also usage of a couple of registers in the EASC...

Apple's pseudo-DMA is PIO, given the processor is doing the actual transfers, it's just that the I/O ASIC (or PAL on the SE and Classic) is effectively a small cache in the middle. The transfer rates are better than pure PIO, but not by a lot, and you're blowing a lot of CPU cycles on SCSI...

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.