The SNx4HC595 devices contain an 8-bit, serial-in,
parallel-out shift register that feeds an 8-bit D-type storage register. The storage
register has parallel 3-state outputs. Separate clocks are provided for both the
shift and storage register. The shift register has a direct overriding clear
(SRCLR) input, serial (SER) input, and serial outputs for
cascading. When the output-enable (OE) input is high, the
outputs are in the high-impedance state.