This is actually my second attempt at becoming a PIC hacker.  Six weeks
ago was my first attempt.  I succeeded at putting a counting sequence
out port D.  At that time I had big arguments with the C compiler over
how to set the port to output (Eventually did it one bit at a time!)
Since I'm trying the MPLAB tutorial, I'm sticking to assembler today.
At least that removes one layer of obfuscation.

Equipment - MPLAB 4.12,  ICD, and 16F874 handbuilt on a board (takes
the place of the "demo" board.  This '874 actually works, as I was
able to get the port-counter to run from power-up without the ICD
attached.

Problem 1.
MPLAB-ICD says it's set for 16F877 and I can't change it.  I thought
maybe that was a setting that would work for all 87x but when I
give it code from a 16F874 compile it complains.

Solution 1.
Upgrade MPLAB to current 5.11 version.  Apparently a free download.
Now I have more choices for processor.

Problem 1.5
The new software requires a firmware upgrade to the ICD board!  This
one's not free but the resulting upgrade is apparently flash downloadable.
So until I get it I won't know how many of the following will be
answered by that fix.

Problem 2.
When I reset the processor it does not go  to PC=0.  It seems to go
to the location pointed to by 0.  Maybe it's supposed to do that
(It's a pretend debugger, after all)

Problem 3.  The register used in the programming example (MPLAB
tutorial) won't update in the debug display.

Solution 3.  Location 0C is a real register, on this chip, anyway.
So I changed it to 21 which is general purpose.  Does Microchip
ever make mistakes? (Large grin)

Problem 4. Now I see a register at A1, not 21, being updated.  This
may be one of those "get the firmware upgrade" things.

Problem 5.  I don't know where the program is running.  Is it on
the ICD board in that PIC or is it on the board I built?  The
reason I ask, besides the upredictable behaviors, is that I can
hold the reset switch down and still step the program.  Where
I come from that isn't normal.  Maybe the PIC is edge triggered.
Maybe a reset doesn't clear everything and send it back to 0.
Mabye I should crack open the datasheet and do some more
reading :-)

Any advice is appreciated.  There will more questions, no doubt...

Barry

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