Timothy Butler

CW6.3/MCF5772 Sporadic inability to break execution with USB TAP

Discussion created by Timothy Butler on Jan 30, 2009
Latest reply on Feb 4, 2009 by Tom Thompson
Using CW 6.3 with a USB TAP, I'm trying to debug what I believe is a sporadic problem with my application on an MCF5272 based board. Normally, I have no problem with the TAP, I can set breakpoints, pause execution, etc. However, when I observe externally that the problem with my application may have occurred, and try to break execution of the processor to see what is happening, I receive the error "CFCSProtocol Plugin : Failed to stop process". The USB TAP continues to show that the CPU is running (LED RUN/PAUSE continuously green) and that there is communication via USB (LEG TX/RX flashing). If I perform a Kill Thread, the debugger is then able to reset the board and reload the application, with no need to cycle power or perform any other external reset.

Could a failure in the application modify the state of the CPU in such a way that it becomes impossible for the TAP to interrupt execution, for example entering HALT due to a fault-on-fault exception scenario? If that's the case, is there something I can trap on before getting into this unbreakable state?

Tim Butler