Roland MC JP

[juanpc2018]

MC-303 1,2,3,4,5
MC-505 its complex inside, many custom IC's
MC-909

the 505 its based on JV-series,
the 909 its based on the XV-series,

JP-8000 & JP-8080 probably are similar to JV-series engine.
0,1,2,3,4,5,6,7
Newer System-8
Hybrid plugin technology, unknown how does work.
i doubt it has a x86_64 inside
who knows.
Unknown how moves plugins between Hardware and Software.
maybe VST CPU plugins have dual architecture.

[giulioz]

Hi @juanpc2018, if you want to know more about how those synth work you can look into their service manual, they usually have a good description of what are the chips inside. If the synth is a combination of a TC6116 (GP4) PCM sound generator and a H8/500 series CPU, then it can be emulated with Nuked-SC55. Some examples of this are the RD500 and the XP10.

Other devices, such as the SC88 and the JD800, have the same H8/500 cpu but different sound chips (the XP and EP chip respectively), which require reverse engineering. I've tried to emulate the XP but it's much more complicated than the TC6116 that is emulated here.

As you stated, the MC-303 uses the TC6116 sound chip, but also a MB90705 CPU which is currently unknown and has no datasheet. Furthermore, we have no rom dump for it.
The MC-505 uses a SH-1 CPU and an XP chip, making it basically identical to a JV1080, very distant to the JV880 we are emulating here. The MC-909 has an XV chip, even more complicated.

The JP-8000/8080 do not use the JV engine, they are based around 4 custom DSP chips called TC170C140AF-003. I've seen some discussions around decapping and reverse engineer them but AFAIK nothing has been done yet. Maybe with a rom dump it could be possible to RE them without a decap, but we don't have that either.