Home Page Forums MAME MAME 8bit Apples - Apple I, II, /// and the 16 bit GS

I've read that one generation of these GTAC ("General Taiwanese Apple Clone") boards omits slot 4 to signal that the Z80 is mapped there.

GSPlus-compatible host file I/O is starting to work in the IIgs driver for the ProDOS 8 version of the protocol. Here's BASIC.SYSTEM CATALOGing MAME's src/devices/bus directory.

Just missed the 0.221 branch, but monochrome output for all 8 bit Apple II video modes is now fixed to be correct and compatible with the NTSC decoder in our HLSL shader (both the original and BGFX versions).

To use it, run -video bgfx, change the system configuration monitor type to Black and White.

Next, go to the Sliders menu, change the screen effect to HLSL, set NTSC A and B Value to 0, set NTSC Scanline Duration to 39.1, and set Enable NTSC to On.

That will change this



into this

They must have used some gfx tool for it, but still that's nice trickery =)

There were paint programs that did 16-color double-hi-res (what's shown here) back in the day, as long as you had an NTSC color monitor.

This wasn't like the CGA situation where you could manipulate it for fun; artifact color was the only color on the 8-bit Apple IIs.

Yeah, something a lot of people don’t seem to realise is that the 8-bit Apple IIs didn’t actually produce colour video as such. They produced monochrome with the horizontal resolution selected so you could produce something close enough to the NTSC colour subcarrier frequency using patterns of alternating black and white pixels. It’s the kind of hardware minimising trick Woz loved to do.

Anyway, it’s been cherry-picked for 0.221, so you won’t have to wait an extra month if you work with tagged releases.

Thanks Vas, I appreciate it

I noticed something when trying to do some debugging with the Apple /// recently, seems the C100-C4FF slot roms are not working correctly. Looks like its just returning 0xff always when debugging.

Got a bit overzealous when I fixed the debugger not touching softswitches. Fixed in https://github.com/mamedev/mame/commit/4c67903fb1ed1ef141817791ddd83ce09cb0678e if you compile your own, or else it'll be in MAME 0.222 at the end of June.

Hi Arbee,

I saw the hlsl stuff which looks super neat and was keen to try it, but when NTSC is enabled in the hlsl filter under Ubuntu, the screen just goes black.

My integrated graphics probably doesn't have the horsepower to drive the hlsl filter, but had to try it anyway 8-)