diff --git a/drivers/avr/i2c_master.c b/drivers/avr/i2c_master.c
index a7364bae0..0acc24642 100755
--- a/drivers/avr/i2c_master.c
+++ b/drivers/avr/i2c_master.c
@@ -1,3 +1,18 @@
+/*  Copyright (C) 2019 Elia Ritterbusch
+ +
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 /* Library made by: g4lvanix
  * Github repository: https://github.com/g4lvanix/I2C-master-lib
  */
diff --git a/drivers/avr/i2c_master.h b/drivers/avr/i2c_master.h
index b4613115d..d68142430 100755
--- a/drivers/avr/i2c_master.h
+++ b/drivers/avr/i2c_master.h
@@ -1,3 +1,18 @@
+/*  Copyright (C) 2019 Elia Ritterbusch
+ +
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 /* Library made by: g4lvanix
  * Github repository: https://github.com/g4lvanix/I2C-master-lib
  */
diff --git a/drivers/avr/i2c_slave.c b/drivers/avr/i2c_slave.c
index dbb9fb0df..4958a0f8e 100755
--- a/drivers/avr/i2c_slave.c
+++ b/drivers/avr/i2c_slave.c
@@ -1,3 +1,18 @@
+/*  Copyright (C) 2019 Elia Ritterbusch
+ +
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 /* Library made by: g4lvanix
  * Github repository: https://github.com/g4lvanix/I2C-slave-lib
  */
@@ -68,4 +83,4 @@ ISR(TWI_vect){
 
     // Reset i2c state machine to be ready for next interrupt
     TWCR |= (1 << TWIE) | (1 << TWINT) | (ack << TWEA) | (1 << TWEN);
-}
\ No newline at end of file
+}
diff --git a/drivers/avr/i2c_slave.h b/drivers/avr/i2c_slave.h
index 7b5dcbdc3..2f4589e9c 100755
--- a/drivers/avr/i2c_slave.h
+++ b/drivers/avr/i2c_slave.h
@@ -1,3 +1,18 @@
+/*  Copyright (C) 2019 Elia Ritterbusch
+ +
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 /* Library made by: g4lvanix
  * Github repository: https://github.com/g4lvanix/I2C-slave-lib
 
@@ -15,4 +30,4 @@ extern volatile uint8_t i2c_slave_reg[I2C_SLAVE_REG_COUNT];
 void i2c_slave_init(uint8_t address);
 void i2c_slave_stop(void);
 
-#endif // I2C_SLAVE_H
\ No newline at end of file
+#endif // I2C_SLAVE_H