> > However, the VOLUME registers (ie, sound registers 0 thru 5) only provide > > 3-bit resolution when envelopes are enabled (normally they would provide > > 4-bits resolution ... it's as if the SAA has gone thru registers 0 to 5 > and > > ANDed with 0xee before using them, whenever envelopes are enabled). Weird > > biscuits. > > Er... don't you mean shifted them down 1?
No, because that would imply that enabling envelopes immediately halves the volume, which is not the case. The resolution just goes down. And I take it you meant shifting-down-on-a-per-nibble-basis since each volume register encodes two amplitudes (stereo ... ) :) > BTW: It's because (I think) of the way the envelopes are used; they're > probably PWM based (as the rest of the chip is), and they're in the pipeline > after the volume generator. So, my guess is that what you've got is this: [...explanation...] > Or something. Thinking about it, this is probably all totally wrong. :) Ummm ... Errr ... well it's probably something like that. Or it could just be some crazy kind of feature (after all, the fact that it's even POSSIBLE to generate 'samples' from the SAA is a kinda undocumented feature .. I'm sure the designers didn't set out to try and allow it. If they had they would've made it a damn site less weird ... Enabling envelopes and mute all channels ??) D a v e
