I hadn’t seen a complete .ucf file posted for the miniSpartan3, and I needed to use a bunch of the pins, so I went ahead and created one. I figured I’d post it here and hopefully save someone else a little bit of time making one. I haven’t completely tested it, so you should use it with caution and double-check it yourself.
Also, while going through the schematic I noticed that several of the pins are input only pins. These are pins A1, A9, and C5. I hadn’t seen this mentioned anywhere, but it’s sorta a big deal, since they’re just scattered across the headers, and particularly A1 is right at the beginning of the I/Os, so it’s likely to catch someone by surprise. I’m guessing the pinout was driven by ease of routing on the two layer PCB, but it seems that there’s still plenty of space available for routing on the bottom layer. IMO an effort should have been made to either put all the input only pins together, or better yet, use them for pins with dedicated input functions, like the DIP switches and USB serial or SPI input. But, I guess it’s too late to make suggestions, so I wanted to at least point this out to hopefully save someone a minor headache.