/* low-level macros for pin i/o manipulation */
#define _INPUT(port, pin)   DDR ## port &= ~_BV(pin)
#define _OUTPUT(port, pin)  DDR ## port |= _BV(pin)
#define _CLEAR(port, pin)   PORT ## port &= ~_BV(pin)
#define _SET(port, pin)     PORT ## port |= _BV(pin)
#define _TOGGLE(port, pin)  PORT ## port ^= _BV(pin)
#define _READ(port, pin)    ((PIN ## port & _BV(pin)) ? 1 : 0)

/* high-level macros for pin i/o */
#define INPUT(x)        _INPUT(x)
#define OUTPUT(x)       _OUTPUT(x)
#define CLEAR(x)        _CLEAR(x)
#define SET(x)          _SET(x)
#define TOGGLE(x)       _TOGGLE(x)
#define READ(x)         _READ(x)
#define PULLUP_ON(x)        do { _INPUT(x); _SET(x); } while(0)
#define PULLUP_OFF(x)       do { _INPUT(x); _CLEAR(x); } while(0)

#define LCD_D4          A,4
#define LCD_D5          A,5
#define LCD_D6          A,6
#define LCD_D7          A,7

#define LCD_EN          A,1
#define LCD_RW          A,2
#define LCD_RS          A,3

#define LCD_PWR         A,0

#define LED0            C,7

#define WIEG_LED0       B,4
#define WIEG_LED1       B,5
#define WIEG_BUZZER0        B,6
#define WIEG_BUZZER1        B,7

...

void foo(void)
{
    OUTPUT(LED0); SET(LED0);
    PULLUP_ON(KEY_UP);

    while (READ(KEY_UP)) ;
    CLEAR(LED0);
}