Think about it for a moment ... the resident debugger allows you to run a test loop, by means of which you can verify proper function of your I/O synchronization code, etc. Say you're running a 33 MIPS 89C4x0 equiavlent in programmable logic ... now you want to communicate with it via JTAG ... the JTAG can, indeed set the hardware state and let it run, but what does it tell you? Yes, you can, after many hours of examination, determine the same thing that you could have seen in 10 seconds under the control of an async-interfaced debug monitor. You then examine (via disassembly) the associated code, make patches using the line-by-line assembler and never having to look up a byte of binary, and then try it again.

There are always may ways to skin the proverbial cat, but some certainly are more convenient than others.

The JTAG is a serial scheme that transfers, at 100 Mbps, a byte in 80 ns, if that's how fast it goes overall, but how fast is that, as compared with the monitor running in real-time? How many bytes have to be transferred in order to get a reading on the state of a microcontroller embedded in programmable logic?

I'm sure it's not impossible, but it seems the resident monitor will be more convenient with devices capable of supporting it, as the 805x is. I really prefer this sort of an approach over introducing additional hardware/software to the process.

I'm still investigating whether KEIL's MON51 has the disassembler and line-by-line assembler, etc. That's the sort of answer I was looking for, namely the recommendation of a product that meets my needs.

RE