What is the reason for the analog/vga board being incompatible with the RAM expansion? I see that they're using the same pins, but could the VGA DAC not just use the other header? I was looking through earlier revisions of expansion boards and it looks like there was at one time a VGA board that was compatible with the RAM expansion.
I ask because I'm working on a CRT project and I'd prefer to avoid outputting digital just to convert it back to analog and maybe adding extra latency as a result.
Also, why does the Analog board have a discrete resistor ladder instead of using a parallel databus DAC?
It's one or the other. The analog output uses the other header, if you have a RAM module plugged in the analog output will not work AFAICT
You can still get analog output and dual RAM by using an HDMI to VGA dongle with a specific chipset. It's called "Direct Video" in the settings. But this means you lose HDMI output, so you can't have both digital and analog outputs at the same time while also sporting dual RAM sticks.
I was hoping to avoid that. Oh well. I still don't understand why the analog board can't use the other set of headers freeing up the ones that the RAM sticks use. Is that bank of GPIOs not fast enough?
I don't know details, but as I understand it, the two banks of pins are more or less identical, and the Mister devs figured out how to use the first to drive DDR3 RAM. At the same time, they figured out how to drive analog video directly from the other bank of pins. But the two approaches are incompatible, because the pins for analog out have to be repurposed to drive DRAM.
So the first bank is always DRAM, and the second bank can be either analog output or DRAM, but not both, because there's not enough pins.
So your choices come down to: analog video, digital video, two banks of RAM. You can pick any two.