[oopic] Re: Providing a clock/time to the PIC

--- In oopic@yahoogroups.com, "minghui1984" <minghui1984@...> wrote:
>
> --- In oopic@yahoogroups.com, Ian Drennan <ianid@> wrote:
> >
> > minghui1984 wrote:
> > > Hi guys, i got a question. As i am dealing with solar tracking
> > > device, i would like to be able to feedback the time to the PIC.
> i
> > > look through the object list and found several options that i
> could
> > > use. Thought i just ask if there is any shorter way of doing it.
> > >
> > > What i need:
> > > Implementing a "clock" by using counters, using the execution
> cycle
> > > and frequency of the PIC (in this case ooPIC is 20MHz). I would
> > >
> > > counter_sec++;
> > > if counter_sec == 60
> > > {
> > > counter_min++;
> > > counter_sec = 0; 'resetting it back to 0
> > > }
> > > if counter_min == 60
> > > {
> > > counter_hrs++;
> > > counter_min = 0; 'resetting it back to 0
> > > }
> > >
> > > if counter_hrs == 24
> > > {
> > > day++;
> > > counter_hrs =0; 'resetting it back to 0
> > > }
> > >
> > > Loop
> > >
> > > My question is will this code work?
> > > how do i make this function keep on running outside the main
> function
> > > Is this a good way of "telling" the time? Cos my device is a
> > > standalone kind so no PC/Laptops will be connected once its
> configured
> > >
> > > In the object list, there are oTimer, oCounter, oClock, are these
> > > suited for the purpose? I looked thru the example, but i dun
> quite
> > > get it. >.<
> > >
> > > Anyone got any hints to how i might make this thing work?
> > >
> > >
> > I would think the oRTC object would be best suited for your
> purpose. It
> > is an object that maintains a real-time clock. It's been a few
> years
> > since I last played with this object but I do remember that it was
> > accurate to about 2 sec in a 24 hour period.
> > Also it will lose its current state when power to the oopic is
> interrupted.
> >
> > Good luck
> >
> > Ian
> >
>
> Thanks Ian, i will look into that. What if my power is not continous?
> anyone else got any other ideas?
>
> One more question. I saw on the archive message that its not possible
> to implement inverse trigo functions, but is there any way i could
> solve inverse functions?
>
> THanks once again
> Minghui
>

Since you only have bytes, unsigned words and integers, trig function
can be a challenge. No floating point, no extended precision and,
worse, no speed.

The way to get around this?

http://www.sparkfun.com/commerce/product_info.php?products_id=8450

Just use an external co-processor.

Richard

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