I now have a working screen. It took a little bit of fiddling, because the ILI9341 lcd controller requires a rather arcane initialisation sequence, so it was, as usual, hard to know if it was my code which was wrong or my wiring. A lot of the time it was silly mistakes in my Z80 code, but it's finally working. And it's very slow — it takes nearly a second to fill the screen with one colour. I can probably optimise my code a little, but not a lot. It'll be fine for small amounts of text, or games where not much moves at a time. But the parallel interface screen should be much faster when it arrives. And when I build this on a PCB and use a 20MHz chip it'll be twice as fast of course. (Actually, I could probably run it at twice its current speed already, if I do some sneaky things in the CPLD…)