>Re PIC16F87X, is the "debug executive program" <--> target PIC >communications interface documentation available? I'm looking for the >sort of information one would need to design a simple debug tool to >utilize the chip's onboard debugging capabilities. > >The documentation I've found indicates the debug data path is RB.6 and >RB.7, but says nothing about data content, format, transmission >scheme... read Microchip's datasheet about the ICD registers in PIC16F87X at http://www.microchip.com/Download/lit/pline/picmicro/families/16f87x/51242a. pdf as you can see there is nothing but additional interrupt source when the execution address match the breakpoint register value after that you have the program control, you may implement whatever you want communication via RB6 and RB7 the reason for choosing those pins is that they are used for ICSP too so your ICD can upload the debugger part easily in blank chips if you want to build your debugger compatible with MPLAB though you have to sniff their protocol between the PC and the ICD and to do the same, otherwise you are free to do whatever you want with your code which handles the interrupt Best regards Tsvetan --- PCB prototypes for $26 at http://run.to/pcb -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads