> > "Embedded systems suffer from another dependency problem: code that
> >  talks to hardware. Encapsulate all I/O operations."
> > and
> > "The OOP folks chant 'encapsulation, polymorphism and inheritance'; of
> >  those three, encapsulation is the easiest and most powerful tool for
> >  building well-written, easy to understand code. It's equally effective
> >  in assembly, C, or C++. Bind 'methods' (code that accesses a device or
> >  data structure) with the data itself."
> >
> > Does anyone have an example or explanation of how to encapsulate i/o in
> > assembly and C?
> >
> > I'll keep looking, but so far what I've found discusses encapsulation in
> > terms of how classes of objects are declared in C++; I haven't figured
> > out yet how to relate that to non-object oriented languages.
>
> In the context of a typical microcontroller program, encapsulation of
> I/O simply means putting all the actual hardware interface in a minimal
> set of subroutines. All interaction with the hardware should be done
> through those routines, rather than by directly changing hardware
> registers. Complex I/O operations should be built on top of the basic
> ones when possible, rather than by talking to hardware directly.

As far as I understand, encapsulation in embedded system assembly/C
programming is not much diff. from structure/module/data-structure
programming.  The objective is hiding as much info. from each other as
possible.  All these hidings come at a price of speed and memory.  The other
end of implementing this, you have the OOP language, and it is an evolution
from the structure/module/data-structure programming.  So in assembly and C,
you implement this according to your budget.  And bettering the budget is
sometime what you are asked to do.

Cheers, Ling SM

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