There's gotta be a way we can't get CGA from a NUC or a pi.
Huh? I guess you mean to say: There's gotta be a way we
can get CGA from a NUC or a pi.
I'm sure that there is, but that's an awful lot of hardware to down convert from an HDMI signal. From a simple users point of view you'll have to get a HDMI->VGA converter then a VGA->CGA converter if you can't find a true HDMI->CGA converter. That's an added expense that is going to outstrip the cost of the Pi right out of the gate. In the high end gaming market, I wouldn't bat an eye buying a top of the line GPU card that costs more than the MB+CPU+RAM combined. In the low end MCU market, it's hard to swallow spending that ratio of money to get such microscopic improvement.
A better solution might be to output VGA then use a $30 converter to convert from VGA-CGA and eschew the whole HDMI nonsense entirely. But I would gamble that might be unsatisfactory as per this thread:
http://forum.arcadecontrols.com/index.php?topic=121893.0I'm just guessing here so someone else might have more information. But it looks like you'll have to leverage the GPIO to create the CGA signals you need. The video controller doesn't even list CGA as a video option and I don't know the specs of that GPU to even take a guess as to whether it's capable of generating CGA directly at all. That puts a greater burden on the software to generate the necessary signal timing. But it does free up the GPU for other tasks if it's possible to use if for other tasks. I imagine it's doable but probably undesirable. Really depends how much work comes out of that.
I can't venture as to anything about the NUC as I haven't looked at it much.
You've also got some crazy ass projects like this:
http://hackaday.com/2011/07/02/controlling-a-cga-monitor-with-an-arduino/I think someone is building a MCU GPU but I can't recall the name intended to drive some really low resolution monitors over USB. Could look into that since something like the Pi or NUC would just shove data down the pipe and let another controller do the lifting.