Hello, I am new to the 8051 architecture. A few questions: I found a general UART example FROM Keil and converted all registers to the C8051F020 architecture. It runs fine in the simulator with proper output to the Serial #1 debug window. I downloaded using the SiLabs plugin dll to the target board. Downloaded the code but no output on the uart 0. I am a bit confused. Found out tonight that this this thing called a XBAR needs to be configured. Weirdest thing I've ever seen before. Anyhow: 1) why does the simulator work and the actual target does not? 2) why can I configure peripherials in debug in the simulator and no matter what I do it works? I didn't know of a crossbar at this point. 3) SiLabs has a configuration utility to configure the crossbar and I can import that to Keil (if I make it under 'c' and not assembler because of duplicate includes probelems with the 'c' code I write in Keil). So what is the mechanism to make/adjust a new startup.a51 file? Or should I use the 'c' produced from the SiLabs config utility. 4) I have found the crossbar chart in the devices pdf file, but should I use SiLabs config utility, or is there a predefined procedure in Keil to configure the crossbar? Thanks very much in-advance for any assistance, C.