Thanks, JDW. Very kind words! I don't do much engineering anymore...but I really like this site! It is definitely rekindling my interest in programming and my old Macs, sometimes with sad discoveries, like
my IIsi disaster. But, great to hang out with such talented and interested users! I also really like the open, friendly and respectful posting standards!
I am not very passionate about the IIe, but I did used to spend many hours trying to make address-swapping hardware devices work in 24- and 32-bit modes. It was a pain, I had full internal access, and not all the problems were solvable (hardware or device limitations). I may have alluded to some things in previous posts like _SwapMMUMode, _StripAddress, related low-memory globals, problems with high-order handle bits by the OS in 24-bit mode (like maybe for 'CODE' resources - I forget), etc.
I think the IIe card is interesting, and I have a full-size IIe and III
somewhere (not working). But, I agree with Patrick about abandoning the specific card design. Besides the Black Box issue, there are likely other practical problems -- 6502 integration, etc. It's a classic 'Make vs. Buy' decision, and in this case Make might be the winner.
Again, I think it's a great card and piece of history to have for its target configuration/OS, but to go forward, it would be important to understand what hardware/internal limitations might be present before leaping down endless rabbit holes. If all that were required were just an external software fix, that would be amazingly lucky (and maybe somewhat unlkikely). But,
maybe Apple might consider making some or all of the technical design specs/docs/source/firmware/VHDL, etc. public domain to support the retro Mac/IIe community? It might be worthwhile sending them an inquiry - never hurts to ask - it's great PR for them to have a thriving retro community.
However, my point in previous posts (which was not to denigrate "Passion Projects" in any way - I have plenty of my own) was that, given other available technology, it seems like it would be much easier to use newer buses and building blocks. For example, you could use a RPi with a Serial Hat -- or maybe a Pico would work. For example, rewrite/recreate the GUI (relatively easy) and hook it USB with an emulator running on the RPi. The presence of WiFi and BLE would also be incredibly useful (and a major advantage over the legacy card). Which one of you zealots is going to port Firefox to the IIe??
Anyway - the video data is relatively low bandwidth and the frame buffer could be passed over USB (or not), along with other types of data i/o channels. Or, if you wanted it to be on some other mac-related bus type, you could mount a Pico to something else -- not unlike the concept behind BlueSCSI.
Just some other suggestions. My weekend folly is that I think I can reassemble a vintage Southbend lathe that is completely disassembled and may have missing pieces. So, I am throwing no stones from my Passion Project glass house!