HD74HC164RP

This 8-bit shift register has gated serial inputs and clear. Each register bit is a D-type master/slave flip-flop. Inputs A & B permit complete control over the incoming data. A low at either or both inputs inhibits entry of new data and resets the first flip-flop to the low level at the next clock pulse. A high level on the input enables the other input which will then determine the state of the first flip-flop. Data at the serial inputs may be changed while the clock is high or low, but only information meeting the setup and hold time requirements will be entered. Data is serially shifted in and out of the 8-bit register during the positive going transition of the clock pulse. Clear is independent of the clock and accomplished by a low level at the clear input.