The 'HC164 and 'HCT164 are 8-bit serial-in parallel-out shift registers with asynchronous reset. Data is shifted on the positive edge of Clock (CP). A LOW on the Master Reset (MR) pin resets the shift register and all outputs go to the LOW state regardless of the input conditions. Two Serial Data inputs (DS1 and DS2) are provided, either one can be used as a Data Enable control.