Hi...
Last night I thought about a general way to build an ice.
Its kind of general ICE, Which can be good for all MCU's.
Very easy to build.
here is my idea.

goals:
Simulates the ROM to the 8051 and run the program step by step.

Componments :
8051 (Or whatever MCU you want)
2 or 3 latches
communication device with PC (Or whatever).
shift register (or any serial/parallel 8bit memory device)


circuit operation:
Welp, to run the MCU Step by step is easyest. We all know
(but some of us didn't notice) that we can control the
clock, instead of crystal (or whatever) we will make a
pulse generator, controlled by latch.
when we do one step == machine cycle == 12pulses.
after one step, we change the data in the latch, which
connect to the AD0-AD7, according to the HEX file.
then we do another step (12pulse) change data ....
Well, maybe its not so easy to do, but its practical, as
a small project.
with a programmed 8051 it'll be easyer to do.

Your opinions please ...
thanx