diff --git a/homework2/src/test4.c b/homework2/src/test4.c
new file mode 100644
index 0000000..f216205
--- /dev/null
+++ b/homework2/src/test4.c
@@ -0,0 +1,11 @@
+//test4.c
+//让2个LED灯交替闪烁
+#include <reg52.h>
+#include "homework2.h"
+void main(){
+	ENLED = 0;
+	ADDR3 = 1;
+	ADDR2 = 1;
+	ADDR1 = 1;
+	ADDR0 = 0;
+}
\ No newline at end of file