Thanks Jim.

Yes, I am using a somewhat newer part, C8051F582. It just happens that I had one of the SiLabs dev. boards, C8051F020 which I am currently using just to learn the SiLabs micro. (Just purchased the '580 Dev board, haven't recieved it as of yet.)

I have not been successful using the on chip DEBUG as you mentioned. For example, if you select Debug in the SiLabs IDE with the Dev Board, I cannot get the "true/real" values of the Crossbar, UARTs, Ports, etc and several other registers. However, if I select "Simulation" debug using the Keil IDE, I can witness the "Real/True" values written to the device.

How are you able to witness the "True/Real" contents of the onboard registers using the onchip debugger, either IDE, SiLabs or Kiel? I am curious. (while NOT is simulation mode)

I did upgrade to Keil uVision 4 this week and I have been working with it. I will select "Simulation" for Debug. This allows me to verify all the registers, such as, UART configuration , baud rate, Crossbar configuration, Read/Write to UARTS and witness the contents all within the IDE.

Once satisfied, I then switch to "Use Silicon Labs C8051xx driver" which allows me to use the on board debugger. I can set breakpoints and do the usual stuff to verify the behavior. Unfortunately, I am NOT able to see the real values of the registers I listed above. This works fine. And I am satisfied with this.

Again, I am definately curious on how you able to do this without using "simulation mode."?

Thanks in advance for your feedback,

Robert