In the thread, "General 8051 questions," I mentioned in passing: "A word of warning when debugging in uVision: The values displayed for R0-R7 (in both the Registers window and by typing "Rn" on the command line) are only ever for Bank zero!" http://www.keil.com/forum/msgpage.asp?MsgID=2260 It seems that this is actually a problem with the Triscend E5 Driver (te5_uv2.dll) rather than uVision itself. Does anyone else have any comments/experience on this?