Today I went back to trying to get my CPLD to work. I suspected that there's probably a problem with my soldering, so I wrote a configuration which set alternate pins to 1 and 0, so that I'd be able to test for shorts. I loaded it and tested all the pins (by connecting them to an LED), and they were okay. So I switched the 1s and 0s and tested again, and this time I found a pin which should have been 1, but was set to zero. It was next to one of the ground pins, and although the pins looked ok through a magnifying glass I plugged in my soldering iron anyway, and ran it between the offending pins. Then I tested it again, and the pin was working properly. I plugged the PCW in, and it also worked properly. Hooray!

I haven't done anything useful with the CPLD yet — so far I just have an LED connected up to A7 which flickers, and I've routed the VIDEO and NSYNC signals through so I can still use them for the external screen.

Speaking of the screen, here's a random picture of Head over Heels on it, after going through the CPLD.