ChanServ changed the topic of ##yamahasynths to: Channel dedicated to questions and discussion of Yamaha FM Synthesizer internals and corresponding REing. Discussion of synthesis methods similar to the Yamaha line of chips, Sound Blasters + clones, PCM chips like RF5C68, and CD theory of operation are also on-topic. Channel logs: https://freenode.irclog.whitequark.org/~h~yamahasynths
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<andlabs>
so there's a module for the TRS-80 CoCo called the Orchestra 90 CC
<andlabs>
and it's a softsynth
<andlabs>
with 5 voice polyphony
<andlabs>
in 1980! on a 6809!
<Lord_Nightmare>
oh WOW, is that dumped or documented?
<Lord_Nightmare>
I've been still trying to track down that bizarre S100 synth card from 1978ish
<Lord_Nightmare>
1977ish, actually... and it got to the point where I emailed James Moorer about it since he was at stanford working on synth stuff in the same department as Chowning (FM inventor) and it was presented at a the 1977 west coast computer faire there
<Lord_Nightmare>
and that's all I've found about it
<andlabs>
yes, the CoCo thing is dumped and emulated
<andlabs>
the source in xroar is literally just reading raw PCM data from an address that the main CPU writes to and mixing that into the audio output
<Lord_Nightmare>
my assumption about how the logistics thing works is as such: either it is a very very fancy dac (i doubt it) or it is an unrolled VLIW (16 bit?) "discrete dsp" with an 8x8->16 multiplier on board and a small amount of ram
<Lord_Nightmare>
the hint is 'a filter with resonator is 12 bytes'
<Lord_Nightmare>
so that means a simple IIR filter
<Lord_Nightmare>
12 bytes i assume is 6 opcodes, and the last one must be a jump back to the first, so 5 opcodes which do anything
<Lord_Nightmare>
its possible there may be a bit which is 'clear PC' so its possible it really is 5 opcodes
<Lord_Nightmare>
er
<Lord_Nightmare>
6 opcodes
<Lord_Nightmare>
i really wish we had better pcb pics, i could probably figure the whole thing out from that
<Lord_Nightmare>
3 dip chips, everything else is NDIP, 1977