The HEF4017 is a 5-stage Johnson decade counter with 10 decoded active HIGH outputs (Q0 to Q9), an active LOW output from the most significant flip-flop (Q5-9), active HIGH and active LOW clock inputs (CP0 and CP1) and an overriding asynchronous master reset input (MR). The counter is advanced by either a LOW-to-HIGH transition at CP0 while CP1 is LOW or a HIGH-to-LOW transition at CP1 while CP0 is HIGH.