Anybody else doing this or reasons not to? I’m laying out a PCB with a RPi connector and the Alchrity AU+ connectors. I’m adding a bunch of RS485 and RS232 ports and buffered GPIOs as well as some other goodies.
Wow, that’s a pretty tight layout!
The only way to know for sure is to build one and see what happens, there always seems to be something you get wrong somewhere in a design and it doesn’t show up until it’s powered up and running. Hopefully it all works right the first time though, sometimes you get lucky. 
Yup, and the errors always show up where you don’t expect it. The whole bottom part of this board had a fatal flaw–the RPi connector is backwards! Glad I caught that before it went out. From experience I’ve learned you can never over-check a board. The worst fail would be if the Alchrity connectors aren’t quite in the right place–there would be no salvaging that. I measured them several times, checked the orientation, etc etc, but… you never know! After revising, the board now feels ready, and I feel really tired…
Boards are back, so far looking good with first turnon of the alchrity board. Next is to attach JTAG to the processor and see if it can talk to the FPGA… Raspberry Pi connection after more testing.
JTAG, processor, RPI interface, Alchitry connection, and Alchitry output control all working. Board is looking good so far with a small batch of haywires. There’s a numbering swap error on the Alchitry board template that caused most of the haywires. External SRAMs, DRAM, SPI ports, serial ports, and motor control outputs still to be tested.