diff --git a/README.md b/README.md
index 4029e34..3e3c766 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,6 @@
 # RESSOURCES
 
+- guide survie piscine embarquee : https://42chips.notion.site/survive
 - atmega328p : https://ww1.microchip.com/downloads/en/DeviceDoc/ATmega48A-PA-88A-PA-168A-PA-328-P-DS-DS40002061A.pdf
 - Getting started with AVR programming : https://github.com/m3y54m/start-avr/tree/master
 - avrdude doc : https://avrdudes.github.io/avrdude/
diff --git a/module01/ex01/main.c b/module01/ex01/main.c
index ca7bdea..7330abc 100644
--- a/module01/ex01/main.c
+++ b/module01/ex01/main.c
@@ -72,7 +72,7 @@ int main() {
 										//   -> 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
+	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
 
diff --git a/module01/ex02/main.c b/module01/ex02/main.c
index c895060..2a60ece 100644
--- a/module01/ex02/main.c
+++ b/module01/ex02/main.c
@@ -48,12 +48,47 @@
 #define BUTTON1	(D, SW1)
 #define BUTTON2	(D, SW2)
 
+// 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)
+#define PERIOD						1000
+#define DUTY_CYCLE					10
+
 // END MACROS
 
-int main()
-{
-	MODE_OUTPUT(LED1);
-	SET_ELEM(LED1);
 
-    return 0;
+int main() {
+	MODE_OUTPUT(LED2);
+
+	// Table 16-4 : set timer in Fast PWM (Pulse With Modulation) mode with TOP = ICR1 (Mode 14)
+    SET(TCCR1A, WGM11);
+	SET(TCCR1B, WGM12);
+    SET(TCCR1B, WGM13);
+
+	// Table 16-2 : Non-inverting mode, the LED will be ON for DUTY_CYCLE% of the time (CLEAR OC1A on compare match, SET OC1A at BOTTOM)
+	SET(TCCR1A, COM1A1);
+
+    // set the period (compare TOP value)
+    ICR1 = TIME_MS(PERIOD);
+    
+    // set the duty cycle to DUTY_CYCLE% of the time
+    OCR1A = TIME_MS(DUTY_CYCLE);
+
+    // start the timer with the prescaler
+    TCCR1B |= (PRESCALE_SET);
+
+	while(1) {
+		continue;
+	}
 }
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