Heres another one. When using Microchips template and header files,
check the settings carefully. It took me hours to figure out that the
watchdog timer was enabled! I looked through the file and checked some
things, but I wasnt thorough, and assumed everything was set in a benign
mode. I still dont know why they would default to WTD on.
Don


Michael Park wrote:
>
> To me, one of the most confusing aspects of PIC programming is the
> conditional testing; i.e., the btfsc and btfss instructions.  For
> whatever reason, I have trouble choosing the right one, and perhaps some
> other newbies have similar difficulties.
>
> Basically, my problem is that I find the "If some condition, skip next
> instruction" model unnatural.  Maybe it's all those years using HP
> programmable calculators, but I much prefer "If some condition, execute
> next instruction, else skip it."  So I use a macro to "rename" btfsc to
> ifset, and btfss to ifclr.  Note the inverted polarity: "Skip if bit
> CLEAR" becomes "If bit SET."  Now I can write code that looks like an
> if/then statement:
>
>         ifclr   STATUS,C
>           goto  nocarry
> or
>         ifset   PORTA,0
>           comf  xyz
>
> The indentation is optional, but I like to emphasize the if/then
> relationship.  As far as I'm concerned, this is much easier to
> write--and read--than code using btfs_.
>
> The macro definitions are trivial:
>
> ifset   macro   f,b
>         btfsc   f,b
>         endm
>
> ifclr   macro   f,b
>         btfss   f,b
>         endm
>
> One could easily add special-case tests for zero, carry, etc., but I
> haven't found it necessary.  I don't have a problem specifying the bit
> to test; it's the branching logic that confuses me, and these macros
> solve that problem for me.
>
> HTH. FWIW. YMMV.
>
> --
> Michael Park
> http://www.seattlerocketworks.com/