Re: A LED as a debugging tool, was: Re: USB as standard debug interface

Chris H wrote:

With a decent ICE you do know and you have the full trace and timings.

An ice can be usefull, but is a very expensive, complex solution. It's usually cpu specific and requires good host software to get right, especially for high internal peripheral count devices. All this costs serious development time and money. Other than bdm, it was just about the only solution available in the old z80, 68xx days, but modern micros have (effectively) made ice obsolete by building in dedicated microcode for the debug function. Imho, microcode is the right way to do this, as you have unlimited access to the actual hardware running in real time and without all the stray capacitive loading and other anomalies that are possible using ice hardware.

In the past, many companies had no choice but to develop systems by the 'code, burn eprom and test' method, such were the cost of ice style development tools, but there are so many solutions now that every engineer involved in a project can afford to have full debug capability on their own machine. I would call that progress, though perhaps the old style tool vendors would disagree...