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

[Ned Konz]

Sorry, ignore the _sfr references in what I wrote previously:

On Tuesday 07 December 2004 9:54 pm, I wrote:
> #define SOME_OUTPUT_PORT PORTD_sfr

#define SOME_OUTPUT_PORT PORTD

> #define SOME_OUTPUT_BIT 2
> #define SOME_OUTPUT_MASK (1<<SOME_OUTPUT_MASK)
>
> SOME_OUTPUT_PORT |= SOME_OUTPUT_MASK; /* set it the hard way */
>
> etc., or you could use macros. But I think my way is nicer.
>
> The compiler will combine these bitfield settings when the register isn't
> defined as volatile:
>
> PORTB2 = 1;
> PORTB3 = 1;
>
> will result in the same thing as:
>
> PORTB_sfr |= (1<<2) | (1<<3);

PORTB  |= (1<<2) | (1<<3);

-- 
Ned Konz
http://bike-nomad.com