Probably better to get this into it's own topic instead of derailing that one even further.
There's a (small series) of interviews planned with the YM designer:
And here's some background:
Since the interview would be held on the same day we discovered this, our very own Steven Segal was so kind to quickly do a first list of technical questions that I releayed to the interviewer via twitter.
Steven Seagal wrote:I typed some questions just in case. Not sure such questions are expected.
It's not vital, mind you, normally we know all the answers.
Those are very technical questions asked in the context of precise emulation of the Atari ST.
- Do the tone, noise and envelope counters count down or up?
(We think they count up)
- Is it true that tone, noise and envelope counters are not reset when the program changes the period?
(We think yes)
- Is it true the envelope counter is reset when the program changes the envelope shape?
(We think yes)
- Are the registers double buffered?
(We think no)
- Are the volumes different on the AY8910 and the YM2149?
- Is the noise different on the AY8910 and the YM2149?
- Does the YM2149 use a 17-bit shift register for noise?
Due to the sheer amount of questions from all over the internet the interviewer decided to split the interview into two sessions, the first one covering mostly historical topics.
This first interview seems to have taken place, awaiting transcription (3 hours worth): https://twitter.com/inversephase/status/880976680805949440
Fortunately Inverse Phase (the interviewer) states he is emulation- and technical-minded, so he'll conduct a second interview just for the technical questions also featuring Stevens list.
Of course there is doubt the designer will remember much, but it's probably worth a try anyway,
Other historical questions ("How do you compare SID and YM?", "Why didn't you add feature X?") are like to have already been asked in the first interview, we'll probably see in an updated blog post from Inverse Phase.
So there's a small window to come up with more questions. Please feel free to add your (technical) questions here. Of course you can tweet your questions, too, but it's propbably good to coordinate with the emulation authors here.