12-stage binary ripple counter
The 74HC4040; 74HCT4040 is a 12-stage binary ripple counter with a clock input (CP), an overriding asynchronous master reset input (MR) and twelve parallel outputs (Q0 to Q11). 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 the state of CP. Each counter stage is a static toggle flip-flop. Inputs include clamp diodes that enable the use of current limiting resistors to interface inputs to voltages in excess of VCC.
Not recommended for new designs (NRND).