So the talk I did at Teardown went up. It’s not visible on their YT page because the audio is a mess. But I kind of like it. It’s surreal and disorienting. https://youtu.be/ZSH8Cz9Ee4g

The audio does clear up about 2/3 of the way through, which means it did capture the Q&A at the end. That was my favorite part. :)

Unchained planar VGA scaler LET'S FUCKIN GOOOOO!

So to demonstrate concretely how weird this mode is, I've slowed down the draw routine so you can see exactly how this gets drawn. Each set of columns is one plane, and it draws each plane sequentially. This was actually not a terribly hard modification to the existing routine since it's working on two independent iterations anyway. I just had to think about it as skipping across the source image by four pixels instead of by one and adding the plane offset to the start.

This is using fixed-point arithmetic but it's not super optimized yet. Optimizing this will be... challenging.

Writing pixels like it's linear to planar video memory is kind of a neat vibe. Very "LED sign board".

You can see my work on the left for drawing horizontal lines. The setup in planar mode is kind of insane - every byte write to video memory now writes to all planes, controlled by a mask register. So you can, with a single byte write, fill in four pixels. That's very neat! But if you're doing something _other_ than four aligned pixels, you need to calculate the mask value, which is less fun.

Figured out the palette. Turns out setting palette entries works better _after_ you switch video modes. 😑 Porting the scaler has also gone well, minus one issue with signed indexes. But this pretty much only works because I've cranked the emulation speed up on DOSBox so it can draw everything in vblank.

I have realized to my horror that VGA doesn't do a 320x200x256 linear framebuffer graphics mode where you can flip pages. Mode 13h utilizes all four planes in "chain mode", so the one page of linear framebuffer is all you get. If you want page flipping, you have to modify this to a sort of interleaved planar mode where every fourth column of pixels lives in a plane. And to switch which plane you're writing to you have to twiddle some VGA registers, which are themselves abstracted behind address/data I/O port pairs. I knew the PC platform was a pile of bad hacks but I am still somewhat aghast that people put up with this. The good news is, this gives you some interesting data pathway tricks you can use to perform faster fills and copies. Which will probably be quite useful, actually.

So now I get to completely rewrite this...

Well this is definitely... something. Palette's all screwed up on the sprite. Not sure what's going on there. But the lines look nice.

Getting to grips with VGA and OpenWatcom.

Finally, a mouse with some personality. Seen in an eBay listing.

@nina_kali_nina Oh, and this was translated by humans (presumably fansubbers) as “But scarecrows!” https://youtu.be/SIbfUyWhkWM?t=1125

@nina_kali_nina You might find these machine mistranslations entertaining.

(I believe this is an idiom that means roughly “stop making excuses” but it entertainingly uses the rhyme between しかし and かかし so it’s literally “there are no buts nor scarecrows”)

It is indeed just a pressure sensor, though. No amount of shouting or noise would activate it, it needed suction. And it does exactly what you’d expect. As long as there is sufficient pressure, the output (which would normally be wired to a heating coil) is turned on. There doesn’t seem to be a limit either. It stays on as long as there’s negative pressure.

The white LED has a neat fade to it, I guess meant to mimic the fade of a cigarette.

Plugged this into a breadboard, gave the red and black wires 3.3V, and it blinks its white LED once on power-up.

I shoved it into the end of a straw and wired an LED to what I assumed was the switched output. I had assumed this output would be active low, as N-channel MOSFETs are cheap and common. But it turned out to actually pull up to the positive input.

Something weirder - this is… I guess for lack of a better term, a “vape controller” I pulled out of a disposable vape. Reportedly some of these are actually microphones, so I was curious to find out how this one worked.

The board is easy enough to remove. But the connections to the neck board are not removable. :/ Also interesting, there’s a single loop of wire around the flyback core. Some kind of feedback mechanism?

Cleaning up this old monitor. Viewsonic Optiquest Q51. It was sitting in a barn for a while, but it worked last time I turned it on. It just needs a bath.

All I did was poke at the power connectors. Maybe this has been a dirty power problem the whole time.

-12V does look noisy, but I don’t think that’s affecting anything in the floppy drive path.

Son of a bitch, it started working again. :[

Ain’t no problem like an intermittent problem because an intermittent problem is not currently a problem.

Alright, I think that'll work.

There's two signals on the 26-pin interface that don't usually show up on the 34-pin one. There's /CHGRST, which Sony does optionally map to pin 1 instead of GND on some 34-pin drives. And there's /HD LOAD, which actuates the head load mechanism. Most 3.5" drives don't have a head load mechanism, so that's by default wired to /MOTOR so the OA-D32W head will load at the same time the motor spins. On the Apricot side, that jumper will be cut as the Apricot ties /MOTOR to GND and a gotek doesn't care about head load.

Wait hold up. ACT installed this IDC connector backwards because there was no room for the tab on the drive board.

(Note the red stripe vs the triangle on the connector. It’s the right way around on the motherboard end.)

So at this point I think I need to figure out which parts of this system are reliable. I can plug the OA-D32W into a greaseweazle and see if it works. Likewise, I can plug a Gotek into the Apricot. Both of those will require converting 26-pin Sony to regular 34-pin floppy. So I guess first I make that adapter.

Digital side looks fine too. Maybe this isn't a problem with the drive at all? That would suck. :[

(This does look twice as fast as you'd expect, but that's because the OA-D32W is a 600 RPM drive!)