diff --git a/module01/ex02/main.c b/module01/ex02/main.c
index e60fb16..91ce870 100644
--- a/module01/ex02/main.c
+++ b/module01/ex02/main.c
@@ -1,75 +1,114 @@
+// #include <avr/io.h>
+
+// // #define FIRST_LETTER_IMPL(x) #x[0]
+// // #define FIRST_LETTER(x) FIRST_LETTER_IMPL(x)
+// // #define PORT_LETTER(PIN) FIRST_LETTER(PIN)
+
+// // global registers
+// #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
+
+// // actions on ports
+// #define TEST_PIN(port, bit)			TEST(PIN ## port, bit)
+// #define TOGGLE_PIN(port, bit)		SET(PIN ## port, 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)
+
+// // LEDs
+// #define TURN_ON_LED(bit)			SET(PORTB, bit)
+// #define TURN_OFF_LED(bit)			CLEAR(PORTB, bit)
+// #define TOGGLE_LED(led)				TOGGLE_PIN(B, led)
+
+// // ELEMENTS
+// #define D1 0
+// #define D2 1
+// #define D3 2
+// #define D4 4
+// #define SW1 2
+// #define SW2 4
+
+// // TIME
+// #define PRESCALE_VALUE				1024
+// #if (PRESCALE_VALUE == 1)
+// 	#define PRESCALE_SET			(1 << CS10)
+// #elif (PRESCALE_VALUE == 8)
+// 	#define PRESCALE_SET			(1 << CS11)
+// #elif (PRESCALE_VALUE == 64)
+// 	#define PRESCALE_SET			(1 << CS10) | (1 << CS11)
+// #elif (PRESCALE_VALUE == 256)
+// 	#define PRESCALE_SET			(1 << CS12)
+// #elif (PRESCALE_VALUE == 1024)
+// 	#define PRESCALE_SET			(1 << CS10) | (1 << CS12)
+// #endif
+// #define TIME_MS(ms)					(((F_CPU / PRESCALE_VALUE) * ms) / 1000)
+
+// int main() {
+// 	MODE_OUTPUT(B, D2);
+// 	TURN_ON(B, D2);
+// }
+
+//////////////////////////////////////////////
+
+#include <stdio.h>
 #include <avr/io.h>
 
-// #define FIRST_LETTER_IMPL(x) #x[0]
-// #define FIRST_LETTER(x) FIRST_LETTER_IMPL(x)
-// #define PORT_LETTER(PIN) FIRST_LETTER(PIN)
+// stringify
+#define STRINGIFY_HELPER(x)			#x
+#define STRINGIFY(x)				STRINGIFY_HELPER(x)
 
-// global registers
+// concatenate
+#define CONCAT_HELPER(x, y)			x ## y
+#define CONCAT(x, y)				CONCAT_HELPER(x, y)
+
+// get argument
+#define ARG_1(v1, v2)				v1
+#define ARG_2(v1, v2)				v2
+#define GET_PORT(args)				ARG_1 args
+#define GET_BIT(args)				ARG_2 args
+
+// actions on registers
 #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
 
-// actions on ports
-#define TEST_PIN(port, bit)			TEST(PIN ## port, bit)
-#define TOGGLE_PIN(port, bit)		SET(PIN ## port, 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)
-
-// LEDs
-#define TURN_ON_LED(bit)			SET(PORTB, bit)
-#define TURN_OFF_LED(bit)			CLEAR(PORTB, bit)
-#define TOGGLE_LED(led)				TOGGLE_PIN(B, led)
-
-// ELEMENTS
-#define D1 0
-#define D2 1
-#define D3 2
-#define D4 4
-#define SW1 2
-#define SW2 4
-
-// TIME
-#define PRESCALE_VALUE				1024
-#if (PRESCALE_VALUE == 1)
-	#define PRESCALE_SET			(1 << CS10)
-#elif (PRESCALE_VALUE == 8)
-	#define PRESCALE_SET			(1 << CS11)
-#elif (PRESCALE_VALUE == 64)
-	#define PRESCALE_SET			(1 << CS10) | (1 << CS11)
-#elif (PRESCALE_VALUE == 256)
-	#define PRESCALE_SET			(1 << CS12)
-#elif (PRESCALE_VALUE == 1024)
-	#define PRESCALE_SET			(1 << CS10) | (1 << CS12)
-#endif
-#define TIME_MS(ms)					(((F_CPU / PRESCALE_VALUE) * ms) / 1000)
-
-int main() {
-	MODE_OUTPUT(B, D2);
-
-	TCCR1B |= (1 << WGM12);				// set timer in CTC (Clear Time on Compare) mode
-										//   -> Table 16-4 : use bit WGM12 to set mode ctc
-										//   -> 16.11.2 : bit WGM12 is located in register TCCR1B
-
-	TCCR1A |= (1 << COM1A0 ) ;			// Enable timer 1 Compare Output channel A in toggle mode
-										//   -> Table 14-3 : alternate functions for PORTB1 is OC1A (Timer/Counter1 Output Compare Match A Output)
-										//   -> 14.3.1 : OC1A/PCINT1 – Port B, Bit 1
-
-	OCR1A = TIME_MS(500);				// set CTC compare value
-										//   -> Table 16-4 : the value to reset the timer is the Output Compare Registers OCR1A
-
-	TCCR1B |= (PRESCALE_SET);
-
-	while(1) {
-		continue;
-	}
-}
+// actions on elements
+#define SET_ELEM(elem)				SET(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
+#define CLEAR_ELEM(elem)			CLEAR(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
+#define TEST_ELEM(elem)				TEST(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
+#define TOGGLE_ELEM(elem)			TOGGLE(CONCAT(PORT, GET_PORT(elem)), GET_BIT(elem))
+#define MODE_OUTPUT(elem)			SET(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
+#define MODE_INPUT(elem)			CLEAR(CONCAT(DDR, GET_PORT(elem)), GET_BIT(elem))
+#define TOGGLE_PIN(elem)			SET(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem))
+#define TEST_PIN(elem)				(TEST(CONCAT(PIN, GET_PORT(elem)), GET_BIT(elem)))
 
+// bits
+#define D1	0
+#define D2	1
+#define D3	2
+#define D4	4
+#define SW1	2
+#define SW2	4
 
+// elements (port, bit)
+#define LED1	(B, D1)
+#define LED2	(B, D2)
+#define LED3	(B, D3)
+#define LED4	(B, D4)
+#define BUTTON1	(D, SW1)
+#define BUTTON2	(D, SW2)
 
 
+int main()
+{
+	MODE_OUTPUT(LED1);
+	SET_ELEM(LED1);
 
+    return 0;
+}
\ No newline at end of file