"In a way, this feature is similar to the YM2149 ADSR envelope. Not technically, but because both features are mostly ignored by Atari and Amiga programmers! :)"

As an Oric-1/Atmos programmer, this line was especially juicy.

Using PAULA's attached mode is so brilliant, btw. I love it when things of this nature are discovered, decades after the fact. We've had a few such revelations in the Oric world too, none as powerful of course at Orics' 1MHZ, but nevertheless, the shoulders of the Atari/Amiga giants are perilously within reach for the climb ..

EDIT: Oh, COPPER and PAULA, paired at the bits. Such a great hack, this one ..

However, it's only as a result of reading this article that I realised the chip is only capable of generating square waves and noise, whereas I'd been under the impression it had some slightly more advanced FM synthesis capabilities. That impression must have come from, decades later, listening to what people could squeeze out of the chip on various Spectrum demos on YouTube. Well, that and the fact that after the 48K beeper the 128K was never going to sound less than incredible. I might not even have had it for a year before switching to the (much less prone to go wrong) C64[0].

Anyway, all of this to say: very interesting project, and I enjoyed the neat reversal trick with the attached voice to get the higher quality output out of Paula.

[0] Actually the Spectrum -> C64 switch was more of a mixed bag than you might think - it wasn't, for example, like games on the C64 were all universally better. On the sound front, the C64's SID chip was a significant upgrade over the AY though, and certainly the most capable sound chip amongst 8-bit computers that I'm aware of. I really wish they'd crammed a SID chip into the Amiga alongside Paula. Or maybe even a dual SID with 6 channels for stereo output + Paula, but, alas... I'm sure it would have been cost prohibitive even if Commodore engineers had the idea at the time.

https://www.pouet.net/prod.php?which=104190

.. could it be run on something like PiMiga?