Finally done with the board! Here's the final rendering of it, which looks basically identical to the previous one other than a bunch of additional traces going to the FPGA. And I've also attached a screenshot of the board layout with the inner layers visible so you can see what's going on under the surface; that's where most of the traces converge toward the FPGA.
I'm about to place the order, and the price has gone up a bit thanks to me not selecting a few important options during the first price estimate. But selecting those options now (double-sided assembly for the bypass caps under the FPGA and vias smaller than 0.4mm) have brought the final price up to $525 for two fully-assembled boards and three unpopulated spares. And then there might be tariffs on top of that, but hopefully not. I haven't actually placed a PCB order since the tariffs went into effect, so I'm not completely sure how that works.
Given the complexity of the boards, it's going to take them 8 or 9 days to fabricate and assemble them versus the standard 2-4 days for fabrication and assembly, but hopefully they'll get to me within the next couple weeks!
Edit: Oh my god, the tariff is $289. I could barely afford this before, but I sure can't now. I hate to say it, but this project might have to wait a while until I can save up enough to actually buy these things.
