Re: [avr-gcc-list] Question about gcc preprocessing and port/pin assignments

[James Washer]

Nice catch Dave... Might have taken a month of sundays to figure out why my 
inputs were ALWAYS 0  ;-)

 - jim

On Mon, 06 Dec 2004 16:55:49 -0500
"Dave Hansen" <address@hidden> wrote:

> From: James Washer <address@hidden>
> [...]
> >Bingo... with Dave (and others help).. I know have the following, which 
> >allows me to work with PORTx, PINx, and DDRx. This allows me to change the 
> >assignment of a pin in one place in the code, and have the DDRx change 
> >along with it.. Cool
> >
> >  - jim
> >
> >
> >#include <avr/io.h>
> >
> >#define DATA1         D, 7
> >#define DATA2         C, 3
> >#define DATA3         B, 3
> >
> >#define PINDEF_PORT(a,b)        (PORT##a)
> >#define DDR(a,b)        (DDR##a)
> >#define PINDEF_PIN(a,b) (b)
> 
> You might simplify some of your macros if you change this one to
> 
>    #define PINDEF_PIN(a,b)  (1<<(b))
> 
> >
> >//Set a pin
> >#define SETPIN(pindef)  PINDEF_PORT(pindef) |= (1 << PINDEF_PIN(pindef))
> 
> Then this one becomes
> 
>    #define SETPIN(pindef)    PINDEF_PORT(pindef) |= PINDEF_PIN(pindef)
> 
> >
> >//Clear a pin
> >#define CLRPIN(pindef)  PINDEF_PORT(pindef) &= ~(1 << PINDEF_PIN(pindef))
> 
> And this one
> 
>    #define CLRPIN(pindef)    PINDEF_PORT(pindef) &= ~PINDEF_PIN(pindef)
> 
> and so forth...
> 
> [...]
> >//Read the value of a pin
> >#define GETPIN(pindef)  PINDEF_PORT(pindef) & (1 << PINDEF_PIN(pindef))
> 
> You'll probably be disappointed with this one.  Try
> 
>    #define PINDEF_PINPORT(pindef)   (PIN ## a)
>    #define GETPIN(pindef)   PINDEF_PINPORT(pindef) & (1 << 
> PINDEF_PIN(pindef))
> 
> Regards,
>    -=Dave
> 
>