diff --git a/.vscode/settings.json b/.vscode/settings.json
index e8c204d..baa76ba 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,5 +1,6 @@
 {
   "files.associations": {
-    "io.h": "c"
+    "io.h": "c",
+    "delay.h": "c"
   }
 }
diff --git a/module00/ex02/main.c b/module00/ex02/main.c
index a036784..e46cddf 100644
--- a/module00/ex02/main.c
+++ b/module00/ex02/main.c
@@ -1,23 +1,102 @@
 #include <avr/io.h>
 #include <util/delay.h>
 
+// test with https://www.onlinegdb.com/online_c_compiler
+// // V1
+//
+// // macro to extract port and bit from a single pin
+// #define _PORT(pin)	((pin) >> 3)
+// #define _BIT(pin)	((pin) & 0x07) // 0x07 is 00000111
+//
+// // helper macros for port name concatenation
+// #define _CONCAT(a, b) a ## b
+// #define PORT_REGISTER(pin)	_CONCAT(PORT, _PORT(pin))
+// #define DDR_REGISTER(pin)	_CONCAT(DDR, _PORT(pin))
+// #define PIN_REGISTER(pin)	_CONCAT(PIN, _PORT(pin))
+//
+// // Macros to set/clear/toggle specific bit
+// #define SET(REGISTER, PIN)		REGISTER |= 1 << _BIT(PIN)
+// #define CLEAR(REGISTER, PIN)	REGISTER &= ~(1 << _BIT(PIN))
+// #define TOGGLE(REGISTER, PIN)	REGISTER ^= 1 << _BIT(PIN)
+// #define MODE_OUTPUT(PIN)		(DDR_REGISTER(PIN) |= 1 << _BIT(PIN))
+// #define MODE_INPUT(PIN)			(DDR_REGISTER(PIN) &= ~(1 << _BIT(PIN)))
+//
+// // Test and check macros
+// #define TEST_PIN(PIN)			(PIN_REGISTER(PIN) & (1 << _BIT(PIN)))
+// #define IS_SET(PIN)			(TEST(PIN) != 0)
+// #define IS_CLEAR(PIN)		(TEST(PIN) == 0)
+//
+// // Pin definitions
+// #define D1 (0 + (1 << 3))   // Port B, bit 0
+// #define D2 (1 + (1 << 3))   // Port B, bit 1
+// #define D3 (2 + (1 << 3))   // Port B, bit 2
+// #define D4 (4 + (1 << 3))   // Port B, bit 4
+// #define SW1 (2 + (3 << 3))  // Port D, bit 2
+// #define SW2 (4 + (3 << 3))  // Port D, bit 4
+
+// // V2
+//
+// // Define the ports
+// #define PORT_B    0   // Port A (represented by 0)
+// #define PORT_C    1   // Port B (represented by 1)
+// #define PORT_D    2   // Port C (represented by 2)
+//
+// // Macros to extract the port and bit
+// #define _PORT_INT(pin)   ((pin) >> 3)            // Extract the port
+// #define _PORT(pin)  \
+//     ((_PORT_INT(pin)) == PORT_B ? 'B' :  \
+//     ((_PORT_INT(pin)) == PORT_C ? 'C' :  \
+//     ((_PORT_INT(pin)) == PORT_D ? 'D' :  \
+// 	'X')))
+// #define _BIT(pin)        ((pin) & 0x07)              // Extract the bit
+//
+// // Macros to set/clear/toggle specific bit
+// #define SET(REGISTER, PIN)		REGISTER |= 1 << _BIT(PIN)
+// #define CLEAR(REGISTER, PIN)	REGISTER &= ~(1 << _BIT(PIN))
+// #define TOGGLE(REGISTER, PIN)	REGISTER ^= 1 << _BIT(PIN)
+// #define MODE_OUTPUT(PIN)		(_PORT(PIN) |= 1 << _BIT(PIN))
+// #define MODE_INPUT(PIN)			(_PORT(PIN) &= ~(1 << _BIT(PIN)))
+//
+// // Test and check macros
+// #define TEST(PIN)			(PIN_REGISTER(PIN) & (1 << _BIT(PIN)))
+// #define IS_SET(PIN)			(TEST(PIN) != 0)
+// #define IS_CLEAR(PIN)		(TEST(PIN) == 0)
+//
+// // Define each LED's port and bit using macros
+// #define D1 (PORT_B << 3 | 0)  // LED1 is on Port B, bit 0
+// #define D2 (PORT_B << 3 | 1)  // LED2 is on Port A, bit 1
+// #define D3 (PORT_B << 3 | 2)  // LED3 is on Port C, bit 2
+// #define D4 (PORT_B << 3 | 4)  // LED4 is on Port C, bit 4
+
+// V0
+
 #define SET(REGISTER, BIT)		REGISTER |= 1 << BIT
 #define CLEAR(REGISTER, BIT)	REGISTER &= ~(1 << BIT)
 #define TEST(REGISTER, BIT)		REGISTER & 1 << BIT
+#define TEST_PIN(PORT, BIT)		PIN ## PORT & 1 << BIT
 #define TOGGLE(REGISTER, BIT)	REGISTER ^= 1 << BIT
-
-#define MODE_INPUT(BIT)		CLEAR(DDRB, BIT)
-#define MODE_OUTPUT(BIT)	SET(DDRB, 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 D1 0
 #define D2 1
 #define D3 2
 #define D4 4
+#define SW1 2
+#define SW2 4
 
 int main()
 {
-    MODE_OUTPUT(D1);
-    SET(PORTB, D1);
-
-    return 0;
+	while(1) {
+		MODE_OUTPUT(B, D1);
+		MODE_INPUT(D, SW1);
+		if (IS_PIN_SET(D, SW1)) {
+			SET(PORTB, D1);
+ 		} else {
+			CLEAR(PORTB, D1);
+		}
+	}
+	return 0;
 }
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