AVR Interface

#include <avr/io.h>

/********************** Macro definitions *******************************/

//                      Access bits like variables:

struct bits {

  uint8_t b0:1;

  uint8_t b1:1;

  uint8_t b2:1;

  uint8_t b3:1;

  uint8_t b4:1;

  uint8_t b5:1;

  uint8_t b6:1;

  uint8_t b7:1;

} __attribute__((__packed__));

#define SBIT_(port,pin) ((*(volatile struct bits*)&port).b##pin)

#define SBIT(x,y)       SBIT_(x,y)

/********************** Hardware dependencies ***************************/

#define LED             SBIT( PORTB, PB0 )

#define LED_DDR         SBIT( DDRB,  PB0 )

#define BUTTON_PULLUP   SBIT( PORTB, PB1 )

#define BUTTON_PIN      SBIT( PINB,  PB1 )

/********************** Code ********************************************/

int main( void )

{

  BUTTON_PULLUP = 1;

  LED_DDR = 1;

  for(;;){

    LED = BUTTON_PIN;

  }

}