1 - That is visible in technical docs, so it is not my discovery.
2 - Hard 'n' Heavy works not on TT, only on it. It is known for years, but I did not went in tracing the reason, because it is not easy on real HW, and emulation of TT with only SW what can do it - Hatari was not much good. Now, I went in trying TT emulation with Hatari 2.0.0 for the first time (1 after it is released) -and I was happy to see that PMMU emulation works, because it is important for my game adaptations. I was able to trace HnH with Hatari, and found the problem in pretty much short time. Writing to odd address of PSG registers - something what probably happens not in any other SW. Because has no sense, and actually, even in HnH most of writes is normal. I disassembled earlier whole game code, but of course did not see those bad lines among 30000 others.
Surprise is that it triggers bus error only on TT.
It is nice that it is properly emulated in Hatari.
3 - Sound mixing ratio - that is simple observation - listening on audio in case of rare SW, what uses YM and DMA audio at once. It is very bad on STE - too loud YM audio in compare to DMA one.
OK, all it was when I did background music playback for STE + TT, Falcon - first with Xenon 2. Sound effects of game go via YM, background music via DMA audio. It was just unbalanced. Then I looked about microwire specs, schematic, expecting that there can set different mixer ratio. Longer story, and there is thread about it in this forum http://atari-forum.com/viewtopic.php?f=15&t=27452&hilit=microwire
Things are simply that in Falcon YM and DMA audio levels are balances, unlike in STE. I would say that they corrected error.
4 - I discovered it when worked on AV - audio video playback for Atari STE. That could work on Falcon too, of course, but there were some unexpected problems on Falcon. Right because that diff. But in that time I had no clue about when exactly that write happens even on ST(E) . So, it needed some testings, experimenting until I realized all it.
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