ICD (CCS and Microchip) plus PIC18 internal osc

mskala · Joined: 06 Mar 2007 Posts: 100 Location: Massachusetts, USA

I'm not quite understanding the wording of documents for CCS ICD (as well as Microchip ICD2).

I don't have a debugger yet but need to design board with it in mind for others.

Question is with PIC18F4520 for example, which has internal 8MHz oscillator, is it truly a requirement for external osc/crystal to use the debugger (not just programmer)?

Did a search and can't find posts specifically mentioning this. CCS and Microchip both seem to say 'target osc must be running' for debug mode, but PIC datasheet description about debug mode lists certain resources of the chip which are used and doesn't mention the oscillator block.

Thanks,
Mark S.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

mskala · Joined: 06 Mar 2007 Posts: 100 Location: Massachusetts, USA

Thanks, I was not performing as much of an intense search. Even with yours, only a couple of the >100 threads are very definite.

But seems like no problem to run internal oscillator along with debug mode, provided that MCLR is not used as an I/O pin.

mskala · Joined: 06 Mar 2007 Posts: 100 Location: Massachusetts, USA

Eventually proved the answer to my own question. I don't know why these things aren't worded more clearly in the documents.

I got the CCS ICD along with the 18F4520 development board (basically a free board with the ICE purchase, great deal).

Once I got the debugger working with a simple LED flasher program, I took off the dev board oscillator and changed to internal osc in the code. The debugger still works.