From: "Dave Hooper" <[EMAIL PROTECTED]> > Um, er. The *envelopes* can be 3 or 4-bit resolution, like the docs imply. > 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? 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: Freq Gen -> Volume Gen -> Output/Envelope Gen -> Integrator/Cut-off Filter/Speaker By the time it reaches the Envelope generator, you've ran out of clock to work with, and as such, you can only get so much resolution on it. So as a result, they reduce the resolution of the volume rather than screw up the sound. Or something. Thinking about it, this is probably all totally wrong. :) Simon
