diff --git a/src/main.c b/src/main.c
index 9b2dd8a..5cea05c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -32,6 +32,8 @@ void delay(unsigned int t) {
 
 #if defined (DEBUG_MPU6050_EULER) || defined (DEBUG_MPU6050_SOURCEDATA) || defined (DEBUG_BLDC)
     SixAxis sourceData;
+#else
+#error Which Debug type are you using? Define DEBUG_XXXX in your compiler options.
 #endif
 
 // float InnerLast;			//保存内环旧值以便后向差分