i do remember that we gave up using an ICE for the last 8051 project i worked on, it would jump around or wouldn't break on demand or something like that. that was around 5 years ago. the project had FPGAs used to arbitrate access to memory and to FIFOs, maybe that had something to do with it. don't know anything more about it, i was doing the firmware not any hardware design. the ICE field rep may have looked at it once but i don't recall any resolution, and we stopped using the ICE. we used an HP 16550 logic analyzer for the tough problems. think i used serial for debug output for development, #ifdef'd out for production. i did most of the debugging and unit tests with the Keil simulator, anyway.

james