diff --git a/.vscode/c_cpp_properties.json b/.vscode/c_cpp_properties.json
new file mode 100644
index 0000000..a9ca4af
--- /dev/null
+++ b/.vscode/c_cpp_properties.json
@@ -0,0 +1,24 @@
+{
+  "configurations": [
+    {
+      "name": "linux-avr-gcc",
+      "includePath": ["${workspaceFolder}/**", "/usr/lib/avr/include/**"],
+      "defines": [],
+      "mergeConfigurations": false,
+      "compilerPath": "/usr/bin/avr-gcc",
+      "cStandard": "gnu11",
+      "cppStandard": "gnu++14",
+      "intelliSenseMode": "linux-gcc-x64",
+      "compilerArgs": ["-mmcu=atmega328p", "-DF_CPU=16000000UL", "-Os"]
+    },
+    {
+      "name": "linux-gcc-x64",
+      "includePath": ["${workspaceFolder}/**"],
+      "compilerPath": "/usr/bin/gcc",
+      "intelliSenseMode": "linux-gcc-x64",
+      "compilerArgs": [""],
+      "mergeConfigurations": false
+    }
+  ],
+  "version": 4
+}
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..e8c204d
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,5 @@
+{
+  "files.associations": {
+    "io.h": "c"
+  }
+}
diff --git a/README.md b/README.md
index 35b5ee2..358ab09 100644
--- a/README.md
+++ b/README.md
@@ -1,11 +1,13 @@
-# RESSOURCES #
+# RESSOURCES
 
 - https://github.com/m3y54m/start-avr/tree/master
 - avrdude 6.3 doc : https://download-mirror.savannah.gnu.org/releases/avrdude/avrdude-doc-6.3.pdf
+- embedded systems : https://en.wikibooks.org/wiki/Embedded_Systems/Atmel_AVR
 
-## ex00 ##
+## ex00
 
 avrdude output without flashing :
+
 ```
 avrdude -p m328p -c arduino -b 115200 -P /dev/ttyUSB0 -v
 
@@ -73,4 +75,4 @@ avrdude: safemode: efuse reads as 0
 avrdude: safemode: Fuses OK (E:00, H:00, L:00)
 
 avrdude done.  Thank you.
-```
\ No newline at end of file
+```
diff --git a/module00/ex01/Makefile b/module00/ex01/Makefile
index 2a483b1..40e9cb4 100644
--- a/module00/ex01/Makefile
+++ b/module00/ex01/Makefile
@@ -8,12 +8,15 @@ AVRDUDE_MCU_TYPE = m328p
 BAUD_RATE = 115200
 SERIAL_PORT = /dev/ttyUSB0
 PROGRAMMER_ID = arduino
+DUMP_ORI = ../../ressources/dump_atmega328p_ori.hex
 
 
 all: hex flash
 
+
 hex: $(TARGET).hex
 
+
 # https://gcc.gnu.org/onlinedocs/gcc/AVR-Options.html
 $(TARGET).bin: $(TARGET).c
 	$(CC) -mmcu=$(AVRGCC_MCU_TYPE) -D F_CPU=$(F_CPU) $(TARGET).c -o $(TARGET).bin
@@ -29,12 +32,12 @@ flash:
 	avrdude -p $(AVRDUDE_MCU_TYPE) -c $(PROGRAMMER_ID) -b $(BAUD_RATE) -P $(SERIAL_PORT) -U flash:w:$(TARGET).hex
 
 
-dump:
-	avrdude -p m328p -c arduino -b 115200 -P /dev/ttyUSB0 -U flash:r:dump_atmega328p.hex
+restore:
+	avrdude -p $(AVRDUDE_MCU_TYPE) -c $(PROGRAMMER_ID) -b $(BAUD_RATE) -P $(SERIAL_PORT) -U flash:w:$(DUMP_ORI)
 
 
 clean:
 	rm -f main.hex main.bin
 
 
-.PHONY : all clean hex flash dump
\ No newline at end of file
+.PHONY : all clean hex flash restore
\ No newline at end of file
diff --git a/module00/ex01/main.c b/module00/ex01/main.c
index 0eefc1c..676b247 100644
--- a/module00/ex01/main.c
+++ b/module00/ex01/main.c
@@ -1,3 +1,37 @@
+#include <avr/io.h>
+
+#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
+
 int main()
 {
+    // DDRx : select direction of the pin
+    //      - 1 = output (pull-up off)
+    //      - 0 = input
+    // PORTx :
+    //      if DDRx = 1 (output mode) :
+    //      - 1 = HIGH (5V)
+    //      - 0 = LOW (0V)
+    //      if DDRx = 0 (input mode) : 
+    //      - 1 = pull-up on
+    //      - 0 = pull-up off
+    // PINx : 
+
+
+    // turn on led 1
+    SET(DDRB, 0);		// make PB0 as OUTPUT
+    SET(PORTB, 0);		// make PB0 as HIGH (LED turns ON)
+
+    // CLEAR(DDRB, 1);		// make PB0 as INPUT
+    // SET(PORTB, 1);		// make PB0 pullup on
+
+    // SET(DDRB, 2);		// make PB0 as OUTPUT
+    // CLEAR(PORTB, 2);		// make PB0 as LOW (LED turns OFF)
+
+    // CLEAR(DDRB, 4);		// make PB0 as INPUT
+    // CLEAR(PORTB, 4);		// make PB0 as LOW (LED turns OFF)
+
+    return 0;
 }
\ No newline at end of file