That actually makes a lot of sense. I'm sure that if I disassemble Prehistorik Man and take a look at the music code, I'll see a lot of the length counter and pitch modulation being used at the same time, because that "small" bug has the potential to break a lot of music. I also assume the bug makes the wave channel more finicky than the other channels, maybe because there's a chance that the length counter does not get restarted when the channel is triggered? (I noticed in Pocket Puyo 2 the wave channel behaves very oddly, consistently cutting out in specific parts of most songs, even when the pitch isn't being changed.)
1 Sep 29, 2020 1:47 pm
Re: Gameboy Color CPU-B buggy revision, effect on chip music? (3 replies, posted in General Discussion)
2 Sep 27, 2020 5:29 pm
Topic: Gameboy Color CPU-B buggy revision, effect on chip music? (3 replies, posted in General Discussion)
Now, I don't have a real Gameboy Color, but instead a GB Boy Colour. Through some testing, I came to the conclusion that... unfortunately or not, depending how you look at it, it's a 1:1 clone of the Gameboy Color CPU-B revision, the buggiest one, mainly known for audio issues. The one reported issue I tested was apparently it completely breaks Prehistorik Man's music, and indeed it does (I'm sad, because I want to hear that awesome soundtrack on a bootleg Gameboy!). It probably has all the other audio problems that are mentioned in the same blog post (I won't post it unless it doesn't break the rules.) (Though, it is compatible with the 5th voice demo by irrlicht, and GBVideoPlayer2 by LIJI32 (if I got the name right,) which both utilize other audio bugs that don't normally work on emulators.) If I wanted to write an audio-intensive demo in assembly for the Gameboy, does anyone know what could completely destroy the audio with glitches? I know code that executes really fast audio-wise might cause it to glitch out, but not much else. I also want to inform others of the extent of the GB Boy Colour's bugginess.
CORRECTION: it also might be a clone of the first revision (CPU-A), if that has all the audio/PPU bugs as the second revision.
3 Sep 25, 2020 4:36 pm
Re: "GB Boy Color" sound quality / any good for chipmusic? (16 replies, posted in Nintendo Handhelds)
Flash cards (especially Everdrive GB) only really work on the GB Boy Colour with a fresh pair of batteries. It also helps to use lithium batteries, because they can provide more voltage/current for longer periods of time. If the batteries are even close to being empty, the GBBC enters a boot loop because either the batteries or power regulator/supply can't provide enough power to the flash cart. Regular carts still work fine, with partly dead batteries.
4 Sep 23, 2020 7:16 pm
Re: "GB Boy Color" sound quality / any good for chipmusic? (16 replies, posted in Nintendo Handhelds)
Believe it or not, I actually ordered it in late July/early August, in the middle of covid. I was surprised how fast it shipped considering the pandemic.
5 Sep 23, 2020 6:42 pm
Re: "GB Boy Color" sound quality / any good for chipmusic? (16 replies, posted in Nintendo Handhelds)
So you aren't looking to buy one brand new??? They're pretty cheap, about $35 USD shipped from Aliexpress (China) (the latest one I ordered this year came in less than 2 weeks!), they're still made today. The one on the bottom is a rare clamshell variation of the Rev. 1 GB Boy Colour that isn't very well documented on the internet.
If the used ones aren't similar to the Aliexpress price, then it's a bit of a ripoff, unless you can get the clamshell one for a reasonable price, because IMO it's a collectible. And of course, it comes with LSDJ! And also, I'm pretty sure the clamshell version doesn't come with the built-in games.
6 Sep 23, 2020 5:41 pm
Re: "GB Boy Color" sound quality / any good for chipmusic? (16 replies, posted in Nintendo Handhelds)
While the original GB Boy (pocket) may have been terrible (too fast clock speed from what I've heard,) the GB Boy Colour is so much better in comparison. It's basically a backlit GBC that has slightly wacky aspect ratio, no IR and runs less than 0.1% slower, from my probing with a logic analyzer and some calculations. The latest revision started production in 2018 (I actually got one just as they released the new revision.) Pressing buttons does cause the audio to buzz and click a bit because of a ground loop, but that can probably fixed with an internal prosound mod or an external ground loop isolator. IMO, it's as good as a real Gameboy/GBC (since the hardware is basically a 1:1 clone of the original,) and works great with LSDJ. It even works with GBVideoPlayer2, a video with audio encoder for the GBC- good enough to get me a temporary copyright takedown on YouTube playing the Pokemon intro theme. So yeah.