diff --git a/Drivers/rf.c b/Drivers/rf.c
index 6b8eb94..8516dd8 100644
--- a/Drivers/rf.c
+++ b/Drivers/rf.c
@@ -20,6 +20,7 @@ extern void Uart_SendHex4(u8 val);
 extern void Uart_SendHex8(u8 val);
 extern void Uart_SendHex16(u16 val);
 extern void Uart_SendHex20(u32 val);
+extern void Uart_SendHex32(u32 val);
 extern void Uart_SendByte(u8 dat);
 
 /**