Yep, gotcha. I was being a bit nannyish I suppose. ZiG's comment was very helpful though, thanks!

Did you see the chip input clock speed in the datasheet, 12MHz. I think we were assuming 32MHz from the Blizzard schematics, and you were talking about using 42.2 MHz in this post. This probably needs a rethink if the blizzard schematic was a typo. The next step up from 115200 baud is 153600, which is a 33% increase, so a 16MHz crystal should do it (but will need a recompile of the windows executable, and I think won't work on linux).