Apptech wrote:
> 
> Microchip documents may well
> contain all the information (although the occasional error
> and misplaced comma which has trivial effect on Olin can
> take a week out of the life of a beginner) but Microchip are
> certainly not "truly expert educators".

Maybe they are, or maybe they're not, but data sheets are intended to be
reference, not teaching, devices.  A good data sheet is complete, accurate,
organized in such a way that information is quickly found, and clear.  But
it is not their role to say "this is how you do it".  That's what
application notes are for.  And seminars, tutorials, books and such.

> There is a vast bow
> wave of assumed competence and assumed familiarity in the
> material which a just ordinary grand-master after a while
> fails to see.

Not sure I agree with the transcendent/grand-master stuff, but certainly
data sheets assume a level of knowledge and competence, as a reference work
should.

By the way, as a writer of tutorials, I agree with your point that there is
a role for introductory material that leads beginners through the "Fire
Swamp" (as you put it).  I just don't agree that there's anything much wrong
with Microchip's data sheets.  Yes, I have found errors in them, but on the
whole I think they're quite good.

> The mechanisms of older PIC addressing are
> arcane and quite unlike those of many almost equally
> venerable IC's (eg the now widely evolved Motorola MCxx68xx
> family which started with the original MC6800 never had the
> banking/paging/partial register issues of the early PICS)

Segmented memory on the 8080, perhaps?

> (I
> started with the MC6800 writing machine code by hand without
> an assembler and was fortunate that the processor had such a
> clean addressing structure).

Ah, memories. I used to write 6502 code in hex, sans assembler, while I
should have been studying for my final years in high school.  The scary
thing is that, nearly 30 years later, I can still remember that 'A9' is "LDA
immediate" and 'A2' is "LDA indexed with X".  And yet my wife says I have a
terrible memory!  :-)

>  It may be that the tutorial material mentioned here the
> other day is close enough to the PIC Osborne 0 for
> beginners. It probably needs a cooperative gaggle of
> beginners and transcendent masters to find out.

As I said, I've had positive feedback on my tutorials, but they are not for
everyone, were never intended to be, and cannot be, because we all come at
the subject matter with different backgrounds and abilities and
expectations.  So the best solution is to have a number of solutions, and
let people choose the educational material that's right for them.


David Meiklejohn
www.gooligum.com.au




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