I have a uc400EFT motion control card & I am running mach3 because I am still undecided about uccnc, I have never had a problem with mach3 personally but know that others have switched for one reason or another.
With uccnc when I enter the diagnostic screen the charge pump indicator is constantly flashing, doesn't seem to make any difference if I set it to active low or select charge pump always on. Did try a search on the forum but couldn't find an answer.