The 'HC194 and CD74HCT194 are 4-bit shift registers with Asynchronous Master Reset (MR). In the parallel mode (S0 and S1 are high), data is loaded into the associated flip-flop and appears at the output after the positive transition of the clock input (CP). During parallel loading serial data flow is inhibited. Shift left and shift right are accomplished synchronously on the positive clock edge with serial data entered at the shift left (DSL) serial input for the shift right mode, and at the shift right (DSR) serial input for the shift left mode. Clearing the register is accomplished by a Low applied to the Master Reset (MR) pin.