On Wed, Feb 18, 2004 at 06:14:47PM +0100, Jan-Erik Soderholm wrote:
> Byron A Jeff wrote :
>
> > Help me out with the 18F. I have a few issues.
>
> Hi.
>
> I pass on the Linux issues. When using a "industry standard"
> environment, there are plenty of tools ;-)

It's not just a Linux issue. What I'm pointing out is that the 16F family
has existed for nearly a decade. There's a lot of infrastructure both
Windows and non-Windows out there. As the new kid on the block 18F support
is slower coming along. I'm aware that everyone has access to the assembler,
and that C18 has some availability, but as usual I look at this from a hobby
prospective, and the 18F infrastructure doesn't seem to be as strong.

>
>
> > 3) Tutorial/Example infrastructure. Sure the 18F is better
> >  but how many examples/tutorials/running code can
> > you find for it.
>
> The 16 and 18 series are not *that* different. Sure, many things can
> be done smarter on a 18-series, but could also be done in a more
> 16-series like way. And since the 18-series are easier to program with
> have less traps, ther are also less need for a lot of toturials...

But when you're getting started, the differences are what gets you. Having
specific examples that work for your actual target can go a long way in
showing a new 18F user how things are done.

>
> > Consider Fr. McGahee's PICUART tutorial/code. A brilliant
> > example of how to leverage real code to show how the PIC
> > serial interface works warts and all. Is there a similar 18F
> > version?
>
> Note that many newer PICs (such as the current 18F1220/1320
> and the comming 16F688) uses the new EUSART, with a 16 bit
> baud rate register. McGahee's code *may* work on those PICs, but
> if so, not in an optimum way. So if someone doesn't update
> that tutorial, it will soon be outdated anyway. Search for "EUSART"
> in the Line Card to get all PICs with that peripherial. I've never
> seen a specific 18-series version, but much of the tips (but maybe
> not the code as such) might still be usuable.

Well Fr. Thomas is back on the list. I'm not sure if he'll volunteer, but
I certainly hope that he does (hint, hint! ;-)

>
> And, even if you don't use Olins develop environment, you could
> always read and leard from his UART macros. They include automatic
> handling of AUSART/EUSART and 8/16 bit baud rate register at build
> time in his macros.

That's good.

>
> > Is there examples of how
> > to really utilize all the cool 18F features like the less segmented
> > memory space, branch instructions and the like?
>
> Not sure what you mean with examples. For specific instructions, there
> are always the data sheet (or the PIC18 Ref Manual with better examples
> for each instruction).  The less segmented memory isn't anything you
> actualy "use", it's just less things to worry about.

Not exactly. One still has to be aware of the access page, the SPF page, and
the fact that only certain instructions can access with full addresses.

But thanks for the reminder of the 18F Ref Manual. As always it'll be a
great read in terms of getting up to speed.

>
> > 4) Silicon issues. Not running at the full 40 Mhz, PLL
> > issues, and the like. I get the willies when the erratta sheet
> > states that operation faster than 4 Mhz is not guranteed.
>
> I think you should get a current status about this. Aren't most of
> this problems (at least in the smaller 18F-PICs) solved now ?

Here's the problem: the very fact that I have to check a current status is
a problem. I have 18F452s, 18F1330s, and upcoming 18F4230's. Depending on
how long ago I got them, their revision number, and the errata sheet that
applies, I may get different unexpected behaviors. Not good.

All I'm trying to say is that the instability is problematic. As a reasonably
experienced PIC developer, it probably wouldn't be as big as deal. But remember
that Wouter started this discussion as a introductory part. What happens when
a newbie gets a 18F part that has a quirk, starts to use it, but gets floored
by some glitch or another.

Stability and support are critical when getting started. That's why I think
that maybe the 16F family may be a gentler start.

BAJ

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