So a lot of people have been saying "Ralph, maybe you should add some arcade systems because you have those arcade machines in there." . And I agreed, after tidying up my code I realized it wouldn't be too hard to add at least one arcade system.
And that arcade system is???
Is it obvious looking at that PCB? No? Ok well it's the Sega System E! Now this arcade system seemed to escape a lot of attention, maybe because they mostly released ports of Sega Master System games. The astute console historian will know people in Japan/USA were like "Sega Master What?", so maybe that explains it.
The brief run down of the system is this, it has 2 SMS graphics chips, 2 SMS audio chips, an almost twice as fast main CPU and double the RAM for each component. Interestingly the ability to run more than one SMS VDP (video display processor) dates back to the TMS9918, which was found in the MSX/Coleco/SG1000/etc. I just don't think anyone actually used it like that until Sega thought they could make an arcade system half decent with it.
Since the Sega System E has 2 graphics processors there are now 2 distinct graphics layers in most of its games. This feature wasn't really used to the full extent it could have been. Hangon Jnr uses it a bit with the background scrolling which is an enhancement over the SMS original.
But anyhow, now the system is in RetroCopy, and unlike every other emulator I'm aware of, it's emulated at the cycle level. Will you hear something you haven't heard before in other emulators? Who knows. 
