ECCP and comparator problem

[just a guest]

Hi,

I want to use the shutdown of the ECCP module by the comparator. But It doesn't work. Here a simply democode:

[Ttelmah]

I think the compiler is probably right!.
If you look at the data sheet, the special event triggers, are _only_available in 'compare mode', _not_ in 'PWM mode'. The idea is that an external input triggers the events. You are trying for a mode, that doesn't exist.

Best Wishes

[Guest]

See the manual of the PIC16F833:

[Ttelmah]

OK. What puzzled me, is that in your posted code, you were trying to enable the CCP shutdown mode, which is specific to CCP operation, not PWM operation.
Which comparator mode do you want?.
I'd guess that the simplest way would just be to use a byte definition, and put the value you want into the register. The CCS versions for this sort of thing, are so damn complcated (with so many interactions), that for my money, they are more work than they are worth...
Remember you must program the comparator you want, to be 'off', before programming the EECPAS register. Writes are disabled that would trigger an immediate shutdown.
Remember you will need to either trigger a processor reset, or poll the status bit, to handle this.
As another comment, you are enabling 'fast_io', but have not programmed the TRIS registers anywhere.

Best Wishes

[Guest]

Hi,

I declare the EECPAS in this way:

[Ttelmah]

You see what I mean about the CCS functions!..
I must admit, I 'wish' that this stuff, was done much more as a set of defines, than as the 'hidden' functions. This way faults could be fixed much easier, and the whole compiler would become more flexible for new chips.
I have tended to do this myself as time has passed, using less and less of the CCS stuff, since it makes support much easier. I'd suggest adding a 'comment', saying what you are doing, or defining the 0x31 value, with a name to say what it does. It'll make future maintenance much easier.

Best Wishes