RGBeter

[RGBeter @RGBeter32X]

@heathy1337 @PointerFunction I knew someone had to have done it before, might be easier to find 2MB chips on old gpus too, using CS0 as another address line then ANDing the two for the new CS is very elegant.

[RGBeter @RGBeter32X]

Found out it's possible to upgrade the VRAM on most PS1s. Stack two SGRAMs except for pin 28, solder a 22Ω resistor onto pin 28 and wire that to pin 121 of the GPU.

Thanks @PointerFunction for helping me test it. Hopefully someone can make use of it.

[RGBeter @RGBeter32X]

@AversiveC @PointerFunction Got tempted by an unused chip select line. No PS1 homebrew uses it right now. Namco system 12 does though.

[RGBeter @RGBeter32X]

@gaab75 @PointerFunction Here's the link to what I was pointed to and used: https://t.co/12ExOEi3ep

[RGBeter @RGBeter32X]

@shmoopyyyy @PointerFunction Nope! Nobody's made any homebrew (to my knowledge) that supports it yet, really just wanted to write it down so the info was out there.

Namco system 12 used 2MB of VRAM+2MB of work ram (same amount of work ram as stock) so maybe some ports are possible in higher quality.

[RGBeter @RGBeter32X]

@Jackhead_ASG @PointerFunction Yes but it'll work on most PS1s, late PU8 through to some early PSONEs. As long as you DON'T have CXD9500 or CXD8514 as your GPU.

[RGBeter @RGBeter32X]

@Dean_Woodyatt @leo__oliveira @PointerFunction Kinda sorta, there were some talks in a server where it was mentioned VRAM would be useful, and I went looking into system 12 to find it. Supposedly a few others have done it before and nothing really uses it yet.

[RGBeter @RGBeter32X]

@leo__oliveira @zaxour @jeffqchen Absolute worst case, 150 ohms is the same E series as 68, for the AES, the extra cent would be doable. Then snk DID get 75 ohm resistors for 3-5.

I hate the input divider more though, 1.5v max is way above the 1vpp in the datasheet.

[RGBeter @RGBeter32X]

@leo__oliveira @zaxour @jeffqchen To ME the worse issue is that, looking at the schematic, it looks like AES overdrives the 1145, 5v*(3k/3k+6.8k)=1.5v, and older systems used a 2.2k instead resulting in 1.2v, which is still too hot for the 1145, then used 68 ohms instead of 75 on the output. Why did SNK do this?

[RGBeter @RGBeter32X]

@KytorIndustries At least the 1981 exists, and it wasn't the last of its kind.

[RGBeter @RGBeter32X]

@illusionrip More interested in that PRO B0 😂

[RGBeter @RGBeter32X]

Got tempted by a cheap MV4 and learned the hard way these are not fun to work on.

That color ram chip tested good but led me to find PRO B0 is dead (PA5 is internally disconnected). If anyone has a source for one that'd be super helpful.

[RGBeter @RGBeter32X]

@zaxour That's a normal Fujitsu one, but the one in your more recent post looks different, when I showed Leo that kind of package on my X'eye he said it looked Yamaha.

[RGBeter @RGBeter32X]

@iVirtualPlays @Villahed94 Ironically a modern screen requires more parts to drive it, not less. Region is handled on main, you'd need to run wires to the jumpers to do that.

Sub has a lot more freedom, at the expense that pretty much every custom chip can and should be replaced.

[RGBeter @RGBeter32X]

Nomad Main is finally ready: https://t.co/fP978PQkqN

[RGBeter @RGBeter32X]

@iVirtualPlays @Villahed94 You gotta generate the gerbers yourself using KiCad, if enough people ask I can make some up and add to the repo. I have a set that JLC likes but different board houses might want them in different formats.

[RGBeter @RGBeter32X]

@iVirtualPlays @Villahed94 Yes, the MAIN board can. You can get all the parts from a VA1-1.8 or VA3 model 2.

315-5660, 315-5487, 315-5700 and 315-5708 are all pin compatible and can be used.

[RGBeter @RGBeter32X]

@MathijsNilwik @Villahed94 I usually just, don't use the grid with repros, I set it to the minimum for most of them, and use free routing mode when I have to. Your reference becomes your scan, and what JLC will allow you to make.

[Studio Halabi @StudioHalabi]

A guide for overclocking your PS3's CELL processor is now publicly available:

https://t.co/rSA1el2qGo

Of course, do this at your own risk!