diff --git a/rotary_encoder_stat.c b/rotary_encoder_stat.c
new file mode 100644
index 0000000..56efe6d
--- /dev/null
+++ b/rotary_encoder_stat.c
@@ -0,0 +1,25 @@
+#include "mc8051fun.h"
+
+
+static uint8_t lastb=0xff;
+static uint8_t hist=0x00;
+
+int8_t rotary_encoder_stat(uint8_t b)
+{
+	if (b==0x00)
+		return 0;
+	if (b==lastb)
+		return 0;
+
+	lastb=b;
+	hist = (hist << 2) | b;
+	switch (hist){
+		case 0b11011011:
+			return 1;
+		case 0b11100111:
+			return -1;
+		default:
+			return 0;
+	}
+
+}