1 files changed, 11 insertions, 0 deletions
diff --git a/03-refactor/src/usart.c b/03-refactor/src/usart.c
index fc58467..a64ad8b 100644
--- a/03-refactor/src/usart.c
+++ b/03-refactor/src/usart.c
@@ -1,5 +1,6 @@
 #include "usart.h"
 #include "delay.h"
+#include "printf.h"
 
 void set_usart1_clock_src(__IO rcc_t* rcc, usart_clk_src_t usart_clk_src)
 {
@@ -78,3 +79,13 @@ void usart_transmit_str(__IO usart_t* usart, const char* str)
     usart_transmit_byte(usart, *(str ++));
   }
 }
+
+void usart_printf(__IO usart_t* usart, const char* fmt, ...)
+{
+  printf_callback_t callback = (printf_callback_t) usart_transmit_byte;
+  volatile void* closure = usart;
+  va_list ap; 
+  va_start(ap, fmt);
+  printf_format(fmt, callback, closure, ap);
+  va_end(ap);
+}