diff --git a/module02/ex03/main.c b/module02/ex03/main.c
index d99515d..6169ea6 100644
--- a/module02/ex03/main.c
+++ b/module02/ex03/main.c
@@ -36,12 +36,6 @@ void uart_tx(char c) {
 	UDR0 = (unsigned char) c;														// 20.11.1 : Put data into buffer, UDRn – USART I/O Data Register (read and write)
 }
 
-ISR(USART_RX_vect) {																// Table 12-7 : we select the code for USART Receive
-	// char received_char = uart_rx();
-	char received_char = UDR0;														// Read received character
-	uart_tx(SWITCH_CASE(received_char));											// Toggle case and send back
-}
-
 // send back caracters received on serial port with case toggling, using interupt and empty infinite loop
 // `screen /dev/ttyUSB0 115200`
 int main() {
@@ -51,3 +45,9 @@ int main() {
 
 	while(1);
 }
+
+ISR(USART_RX_vect) {																// Table 12-7 : we select the code for USART Receive
+	// char received_char = uart_rx();
+	char received_char = UDR0;														// Read received character
+	uart_tx(SWITCH_CASE(received_char));											// Toggle case and send back
+}