as of now I have added the Date library as a submodule in order to have
log messages in the correct time zone
please update your submodules by doing:
```
git submodule update --init --recursive
```
2 Pulse channels:
- 8 level pulse duty cycle, DAC mode(just ignores duty cycle)/pulse wave mode, 4 bit volume.
- Furnace support PCM playback in pulse channels with duty cycle ignore mode.
Sawtooth:
- nothing but 6 bit volume (8 bit accumulator in technically) and 12 bit frequency (periodic).
VRC6 instrument:
- 6 bit Volume macro for finer sawtooth volume handling, also 3 bit Duty cycle macro for pulse channels.
Duty, PCM mode command and Duty macro affects for pulse channel only.
It means Custom wavetable sound generator logic on Bubble System.
It's wavetable select and volume is controlled by single AY-3-8910 IO for both channels, Another AY-3-8910 IO is used for reading sound status.
Schematics: http://pdf.textfiles.com/manuals/ARCADE/K-R/Nemesis%20[Schematics]%20[English].pdf (Nemesis, derivative of Bubble system)
Bubble System 2 channel Wavetable sound generator logic is configuration with K005289, 4 bit PROM and DAC.
K005289 controls pitch and 5 bit address generator per channel, Waveform select and Volume control is tied to AY-3-8910 ports. (each port for per channels)
these configuration is better known as K005289, the part of logic.
furnace emulates this configurations as single system, waveform format is 15 level and 32 width.
its 16 channel wavetable/PCM chip, with (optional) stereo support.
Its also has envelope, this feature has similar as AY PSG's one but its shape is also stored at RAM, and each nibble in envelope data is for each output: so i decided to added some feature for more stereo-ish envelope.
Split: Envelope shape will be splitted to Left and Right half for each output.
HInv, Vinv: Envelope shape will be Horizontally/Vertically mirrored the left one.
Max sample length is sample bank size of Seta 2 arcade hardware (currently not emulated yet, nor it doesn't support on VGM).
Chip id is temporary, it can be changed with to suggestions.
