The 74HCT595 is an high speed CMOS device that is designed to be pin compatable with 74LS low power Schottky types.

An eight bit shift register accpets data from the serial input (DS) on each positive transition of the shift register clock (STCP). When asserted low the reset function (MR) sets all shift register values to zero and is indepent of all clocks.

Data from the input serial shift register is placed in the output register with a rising pulse on the storages resister clock (SHCP). With the output enable (OEሻ asserted low the 3-state outputs Q0- Q7 become active and present th

All registers capture data on rising edge and change output on the falling edge. If both clocks are connected together the input shift register is always one clock cycle ahead of the output register.