nesdev.org

If the WX, WY and window on flag conditions are all true at the same time, the PPU goes into window rendering mode. It then draws the window on each following line, starting at X position specified by WX, and the line counter is incremented for each consecutive line. (What I'm calling the line coun...

AFAIK, the only open source DMG/GBC emulators that, in part, focus on debugging tools (especially GUI ones) are endrift's mGBA and my own GBE+. If you're looking for CLI debugging stuff, GBE+ is pretty advanced. I've been holding off on improving the debugging GUI (and expanding it to GBA stuff) unt...

If you're going to be writing your own tests, having (close to) 100% compatibility isn't really an issue. That is to say, if you want to do your own low-level tests of hardware behavior (the actual Game Boy, not the MBC itself) you often don't need anything much fancier than 32KB of ROM and maybe th...

For the cart flasher, I got mine from BennVenn. He's based in Australia if I recall correctly, so for you it's international shipping regardless. There's this flasher from someone based in Spain, so that might be more favorable to you. Unfortunately, both BennVenn's and JRodrigo's flashers are sold ...

Confused when you say you can put a ROM on the flashcart, and later you say if you don't have a flashcart reader you need to print visual statuses. How would i even get the ROM to the flashcart without a flashcart reader, isn't that what you use to R/W to it;o? Well, for me, I use Linux. There are ...

Btw why would i want several GameBoys, one expects them to break? You'll need at least two if you want to do hardware tests on multiplayer stuff (standard 2-player stuff e.g. Pokemon battles/trading). It's not necessary, but yes, having a backup is always a good idea. Game Boys are pretty durable a...

In that case it LY also reset, cause otherwise it would go out of sync with that clock right? Already mentioned it here but yes, LY gets reset to 0 when the LCD is disabled. Otherwise weird things would happen. And also, when it's disabled, is the clock stopped, or does it run and it just resets wh...

GB documentation is a mess. Stuff is scattered all over the place in different resources. And on top of that, we're still learning new things even today. Just look at gekkio, endrift, or LIJI32's work. I've been tackling lots of crazy accessories as well (Barcode Taisen Bargidun, the Barcode Boy, th...

Ah, but what if you write to LY so it resets? I think this is another famous example of how poor Game Boy documentation can be. That bit of info is from Pan Docs, which is incorrect. Any writes to LY while the LCD is enabled are ignored. When the LCD is disabled, LY is forcibly set to 0, and since ...

but what happens when the actual flag to check is set, does a check occur at that moment, or will it wait till the next LY increment? When you write a new value to LYC, this forces an immediate comparison between LY and LYC. You can use this to manually fire a STAT interrupt via LYC. The game Sagai...

So to be clear, the entire time the LCD is warminig up again, LY is read back as zero, yes? Not sure. Maybe someone else knows. If you turn it on, I'm assuming that it functionally "works" in the sense that interrupts and DMAs and anything related to the LCD starts up again, just that the...

2. when you enable the LCD again via LCDC.d7 0->1, how long does it take before the LCD starts rendering again? Can it start plotting pixels at the top left of the display again immediately? Does it take 16ms or so? Can't verify the 1st question, but the second question has been settled for a while...

This looks like it's DMA related. I think the overwhelming majority of GBC specific graphical issues are related to the new HDMA or GDMA in some way (not doing them at the right time or not doing them correctly, mostly the former imo). My guess here is that maybe you trigger only one GDMA where you ...

You should check out some of the newer Wipeout games or at least their remastered versions. Specifically, I picked up Wipeout Omega Collection last weekend, and even some of the lower class races get pretty intense. I think a lot of people have the impression that F-Zero GX was the pinnacle of futur...

Honestly speaking, the problem could be anywhere. Even if you had all the basic requirements necessary to run blargg's tests (i.e. a complete GBZ80, some interrupts, timers, LCD rendering, etc), if you implemented something incorrectly, that would mess other things up. I would highly encourage you t...