Why don't you think of a board such as the one from Cygnal with the C8051F124 chip on it. This board is $149 and supports JTAG and full debugging support via hardware breakpoints without the need to purchase an expensive emulator or use a kludgey debugging monitor. This kit from Cygnal includes a everything you need to get started with what is quite possibly a chip that has every peripheral you would ever need. The board has a rugged 96-pin DIN connector on it that gives you access to all processor signals, headers for each of the 8 ports for easy scope/analyzer hookup, and support for the JTAG hookup to your PC comm port. There is even an RS232 port connected to one of the processor's two UARTs that is pinned out to a standard PC compatible D9 connector. To build prototypes all you have to do is either make a quick turn PC board or a hand wired PC board that interfaces to the DIN connector. I have a set of photos of this type of setup on my 8052.COM home page that you can look at. One cool part about this setup is you only have to buy the Cygnal board once and you can make multiple versions of the prototype extension.

The best part is this processor is STATE OF THE ART.

Michael Karas