#include <avr/io.h>
#include <util/delay.h>

// #define FIRST_LETTER_IMPL(x) #x[0]
// #define FIRST_LETTER(x) FIRST_LETTER_IMPL(x)
// #define PORT_LETTER(PIN) FIRST_LETTER(PIN)

#define SET(REGISTER, BIT)			REGISTER |= 1 << BIT
#define CLEAR(REGISTER, BIT)		REGISTER &= ~(1 << BIT)
#define TEST(REGISTER, BIT)			REGISTER & 1 << BIT
#define TOGGLE(REGISTER, BIT)		REGISTER ^= 1 << BIT

#define TEST_PIN(PORT, BIT)			PIN ## PORT & 1 << BIT
#define TOGGLE_PIN(PORT, BIT)		PIN ## PORT |= 1 << BIT
#define MODE_INPUT(PORT, BIT)		CLEAR(DDR ## PORT, BIT)
#define MODE_OUTPUT(PORT, BIT)		SET(DDR ## PORT, BIT)
#define IS_PIN_SET(PORT, BIT)		(TEST_PIN(PORT, BIT)) == 0
#define IS_PIN_CLEAR(PORT, BIT)		(TEST_PIN(PORT, BIT)) == 1
#define TURN_ON(_PORT, BIT)			SET(PORT ## _PORT, BIT)
#define TURN_OFF(_PORT, BIT)		CLEAR(PORT ## _PORT, BIT)


#define D1 0
#define D2 1
#define D3 2
#define D4 4
#define SW1 2
#define SW2 4

#define TIME 500

#define LED1 B0

int main() {
	MODE_OUTPUT(B, D2);
	TURN_OFF(B, D2);

	while(1) {
		TOGGLE_PIN(B, D2);
		_delay_ms(TIME);
	}
}