If anyone is interested, you could do some PCE chiptunes with an XM tracker. I'm writing a MOD player for the PCE, but there are some other branch off formats that I'm doing as well.
If anyone wants to start doing some tracks, here's the info you need to know:
2 channels are resevred for 8bit sample playback - so two MOD style sample tracks. The output frequnecy is 7kz. This is not related to *notes* as they can be up to 32khz, just that all output from those channels will be downsampled and mixed to 7khz 10bit output. They're fixed to channels 2 and 3. It's best to keep the samples at a lower sample rate since they will be downsampled - something like 8khz for C-3.
4 channels for 32sample pattern tones. There's only support for forward looping and the looping envelopes must be at the start and end of a sample/pattern. ADSR envelope postions are fine/unrestricted though. Frequency sweeps/slides, panning and panning envelope, etc are doable as well.
If your tracker supports it, one channel can LFO another channel. Assign channel 0 as the LFO and channel 1 as the channel to be modified. The data in channel 0 will oscillate the output frequency on top of channel 0. You can sweep/slide the frequency of channel 0 in addition. Also in addition the LFO of channel 0 can be set to different multipliers (I can explain more on this later).
Channels 4 and 5 individually can be set to noise generation and with ADSR as well. Otherwise in normal modes channels 0,1,4,5 are 32byte sample mode.
So there you go, a six channel setup. Note: The wav sample channels could be extended to 3, but it adds processing overheard and not recommended since I want to keep the format simple.
