The HEF4040B is a 12-stage binary ripple counter with a clock input (CP), an overriding asynchronous master reset input (MR) and twelve fully buffered outputs (O0 to O11). The counter advances on the HIGH to LOW transition of CP. A HIGH on MR clears all counter stages and forces all outputs LOW, independent of CP. Each counter stage is a static toggle flip-flop. Schmitt-trigger action in the clock input makes the circuit highly tolerant to slower clock rise and fall times.