#1318 OSC3 not set on waveform $0

[Leandro Nini]

When changing to waveform zero (no waveform selected) the OSC3 register is not changed.

The attached test does the following:
* set pulse with pulse widht $fff, OSC3 will read $00;
* set pulse with pulse widht $000, OSC3 will read $ff;
* set no waveform, OSC3 will still read $ff;
* wait ~3 secs, OSC3 should now read $00;

The fix is trivial, will post it later as I don't have the code at hand, if someone in the meanwhile can confirm the test works as expected.

[gpz]

tested and modified the test a bit, see https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/SID/osc3-wave0/

it works on old and new SID... as with other bitfade things, the time it takes varies significantly with temperature, and is generally longer on 8580

[Leandro Nini]

Great, here comes the patch.

[gpz]

ok, it looks nothing like on the real thing though.... on 8580 it prints a lot of different values before it goes to 0 (around 40 values in around $400 frames on cold machine). on 6581 its something like 10 values and perhaps 200 frames. No idea how much work it is to make it more "real" - but if it isnt too much hazzle, it'd be nice if you could make it so :)

anyway, patch applied in r38798

[Leandro Nini]

Yeah, actually the individual bits fade down at different speed, same for the shift register reset.
Would indeed be nice to have a realistic pattern, I'll add it to my TODO list.

[gpz]

closed via patch #248