DEBUG macro in uart.h, enabled by default in makefile

makefile

@@ -11,6 +11,9 @@ QEMU_MACHINE_NAME = uno
 # Compiler flags
 CFLAGS = -std=c2x -Wall -Wno-array-bounds -mmcu=$(MCU) -DF_CPU=16000000UL -O3
 
+# Comment the following line to disable UART debugging (see uart.h)
+CFLAGS += -DDEBUG_UART_ENABLED
+
 # Source files
 SRCS = $(wildcard *.c)
 

uart.h

@@ -1,7 +1,20 @@
 #pragma once
+// Simple UART library for ATmega328P
+
+// Define DEBUG_UART_ENABLED to enable debug messages
+#ifdef DEBUG_UART_ENABLED
+#define DEBUG(message) UART_println(message)
+#else
+#define DEBUG(message) ((void)0) // Define as no operation (NOP)
+#endif
 
 #include <stdint.h>
 
+// Initialize UART
 void initUART();
+
+// Transmit a byte over UART
 void UART_transmit(uint8_t data);
+
+// Print a formatted string over UART
 void UART_println(const char* format, ...);