On Sun, Aug 12, 2001 at 12:41:44PM -0700, James Salter wrote:
> Hello Piquers!
>
> 628 is a charming chip, so I got a stash of them.  Can anyone recommend an
> informational resource(s) for migrating from '84 to '628?

They are a bit too new for such resources. Of course they have the standard
modules that most midrange pics have. I've found that Microchip's Midrange
manual has a lot of detail and examples.


>  Hoping for a practical guide, like an FAQ, or some detailed project
> examples.  Mostly, it would be helpful to read a "plain English" explanation
> of all the new pin functions, and some logical scenarios for using those
> functions.
>
> Yes, I already printed out and perused the 62X data sheet.  Sure, it is a masterpiece of succinctness, all 158 luscious pages of it, but it is hard to penetrate, hard to get straight answers.  That is, it is not written in an introductory style.
>

Correct. It's a reference manual. The midrange manual has a bit more of
a tutorial format.

> What makes 62X especially tricky for me is way each pin can do multiple new
> functions, and defaults to those new functions, and must be configured to an
> intended purpose.  I am especially confused by the way the MCLR pin is
> disabled in a certain mode.  How do you program the chip when the MCLR does
> not respond?

That's simple enough. That function is disabled in programming mode.

> I thought MCLR was necessary to initiate the programming process.

It is. But that function is disabled in programming mode. As with all PIC
I/O pins, it's an input at reset. If a programming voltage is presented on
the pin, it'll go into programming mode and not start regular operations.

>  For ICSP, can MCLR be floated, or should it be pulled up/down?

Not sure about this one, as I never use ICSP.

>  And LVP is also a new twist I don't yet understand.

LVP allows for programming the part without having to utilize a programming
voltage. You can build 5V only programmers using LVP. Take a look at my
trivial LVP pic programmer here:

http://www.finitesite.com/d3jsys

Note that it doesn't have a high voltage Vpp section. Also two quick notes:
I haven't tested it with a 16F62X part yet, and I haven't personally tested it
with any DOS/Windows software. If anyone happens to do either, please drop me
a line so that I can update the page and point folks to the software.

>  These are the kinds of riddles for which a cheat sheet would be graciously
>  appreciated.

>
> Methinks the 16F62X deserves a book: "PIC16F62X for Dummies"
>
> Thank you for any illumination you may provide.

Hope some of this helps.

BAJ

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