>> Only if you consider three instructions to disable the analog inputs
>> "difficult".
>>
>I agree, simple to port if you read the datasheet.

Anything but simple. If all you have used is the 84, why would you even
suspect that you better read the section on the comparator if you aren't
going to use it?

And on the 84, you really don't worry about banking, so when you go to set
the TRIS register and all of a sudden all your data changes, how do you
have any idea what's going on?  You're not expecting that to happen, it
never happened before, without an experienced mentor you are up the creek

An oh yeah, the 84 code is almost always absolute, and you can't just
mechanically change a few things here and there, you need to understand
what constants are constants and what constants are memory addresses, if
it even occurred to you that what used to be a GPR is suddenly an SFR.

It's simple IF YOU ARE EXPERIENCED.

>>> Most of
>>> the 84 code out there is absolute and horribly written.
>>>
> some is OK. But that is irrelevant

Well, of course mine is good.

> When I 1st started using PIC in 2003 I had no difficulty in getting
> '84 assembler source code to  run  on  '877.  Later  I  had  no
> difficulty porting stuff to '628

I write most of my code (for the 8 bit parts) in assembler, and write it
to be processor agile.  Not hard if you plan a bit.  But if you are using
an 84, the odds are real high you don't even know what to plan for.

> You learn lots porting. If you are simply going to build a
> "one off "  100% clone of existing design and learn nothing,
> then maybe use 16F84.

You are right that porting can be a terribly valuable experience.  In
fact, most painful things seem to be valuable experiences.

And while I still believe that the 16F84 is a good PIC to learn on,
especially if you have no other microcontroller experience, I also think
that it is almost never the right part for the -next- project.

Many, many hobbyists have a dread fear of moving beyond the 84.  While I
see a lot of reasons you may want to use one, I don't fully grasp why so
many folks view another PIC as so terrifying.  Many folks, even when they
get past the 84, still keep their menu pretty limited.

And I find those particular menus rather surprising.  The 628A seems to be
the next most popular, at least of 18 pin parts.  OK, it adds more memory
and a serial port, but lots of hobbyists will add an external A/D rather
than moving to a part with an onboard A/D.  The 716 has I think 4 A/D
ports, and it only costs a buck. OK, I exaggerate - $1.01 quantity one
from Newark in a DIP.  For under $3 you can get an 88 which has gobs of
everything; memory, serial, I2C, A/D, adjustable oscillator.  IMO, this is
the 18 pin part for the hobbyist, assuming you are only going to keep one
type of part in the drawer.  Even the 648A offers double the memory for
another quarter.  So why the 628?  Mystifies me.

--McD


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