diff --git a/debug.c b/debug.c
index db31482..9bc2af2 100644
--- a/debug.c
+++ b/debug.c
@@ -8,7 +8,7 @@
 #if USE_DEBUG_UART
 
 // debug printf
-int PRINTF(const char *format, ...)
+int _DO_PRINTF(const char *format, ...)
 {
     va_list args;
     int len;
diff --git a/debug.h b/debug.h
index 8091e52..ddaa470 100644
--- a/debug.h
+++ b/debug.h
@@ -11,12 +11,20 @@
 
 #if USE_DEBUG_UART
 
-int PRINTF(const char *format, ...) __attribute__((format(printf,1,2))) ;
+int _DO_PRINTF(const char *format, ...) __attribute__((format(printf,1,2))) ;
 void PUTSN(const char *string, size_t len);
 int PUTS(const char *string);
 void PUTNL(void);
 int PUTCHAR(int ch);
 
+#define PRINTF(format, ...) do { \
+    if (VA_ARG_COUNT(__VA_ARGS__) == 0) { \
+      PUTS(format); \
+    } else { \
+      _DO_PRINTF(format, ##__VA_ARGS__); \
+    } \
+  } while (0)
+
 #define dbg(format, ...) do { \
     if (VA_ARG_COUNT(__VA_ARGS__) == 0) { \
       PUTS(format); \