James Newton wrote:

> One of THE most brilliant things I've ever seen.
>=20
> #define _TRIS(pin)            pin(_TRIS_F)
> #define _TRIS_F(alpha,bit)    (TRIS ## alpha ## bit)
> #define _PORT(pin)            pin(_PORT_F)
> #define _PORT_F(alpha,bit)    (R ## alpha ## bit)
> #define _LAT(pin)            pin(_LAT_F)
> #define _LAT_F(alpha,bit)    (LAT ## alpha ## bit)
> #define _WPU(pin)            pin(_WPU_F)
> #define _WPU_F(alpha,bit)    (WPU ## alpha ## bit)
>=20
> #define pinSwitch(f)       f(A,2)        //Switch, INPUT , pin RA2
> #define pinLed(f)          f(B,5)        //Led, OUTPUT , pin RB5
>=20
> _TRIS(pinSwitch) =3D 1; //make pin an input
> _WPU(pinSwitch) =3D 1; // turn on internal pull-up
> _TRIS(pinLed) =3D 0; // make pin an output
>=20
> while(1){ =20
>  _PORT(pinLed) =3D ! _PORT(pinSwitch)
> }
>=20
> Why is it so brilliant? Because now, you can write a standard code librar=
y,
> without any pin assignment crap in it, and simply include a standard .h f=
ile
> (pins.h for example) which you make for each project. In that file, you d=
o
> the=20
>=20
> #define pinSwitch(f)       f(A,2)        //Switch, INPUT , pin RA2

I do this a bit different -- but also using macros :)

When writing a generic module that uses any processor resources (I/O
pins or other special registers), I use macros for these items in the
module. The module header then has a section where I describe the
required macros. Compiler is set up to fail if a macro is missing. The
application using the module needs to provide the macros.

This becomes then as simple as requiring e.g. macros SET_MODULE_OUT and
GET_MODULE_IN, which in the hardware definition of a project could then
be defined as

  #define SET_MODULE_OUT( arg )  LATB4 =3D !arg
  #define GET_MODULE_IN()        RB3

(LATB4 and RB3 are Hi-Tech's names for the port pins. RB3 is port B3.)

And the while loop would be
 =20
  while( 1 ) {
    SET_MODULE_OUT( !GET_MODULE_IN() ); // becomes LATB4 =3D !RB3;
  }

One advantage is that there are no (reasonable) limits to the complexity
of the macros, so if on a given hardware you need to do something
different, you can do that without messing with the module code. Like in
this case change the polarity of the output.

Gerhard
--=20
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