Thanks to all who have pointed at Microchip's DS51242A, "PIC16F87X Debugger Control". I've studied that so hard for the last week I can almost recite it from memory, and still have some fundamental questions on how this works. Here's the most mind-boggling: The document states on page 10 describes how the debugger code gets control: "As the processor vectors to 0x2004, the CPU will fetch and execute the instruction at this address. Therefore, address 2004 must be programmed with a GOTO opcode, where opcode is pointing to the beginning address of the debug code." I really can't wrap my head around this statement because it would seem that the current contents of PCLATH would determine which page of memory the GOTO statement would transfer to. Is there some special form of GOTO that must be used? This is one of several questions pondered by Myke Predko, Bob Ammerman, Tony Nixon, Dmitry Kiryashov, Olin Lathrop and Alejandro Lavarello back in May of this year. If answered, I can't find it in the archives... Any clues? Thanks, Steve -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics