Eight-bit shift registers with Schmitt-trigger inputs and with output registers

The SN74HCS594 device contains an 8-bit, serial-in, parallel-out shift register that feeds an 8-bit D-type storage register. All inputs include Schmitt triggers, eliminating any erroneous data outputs due to slow-edged or noisy input signals. The storage register has parallel outputs. Separate clocks and direct overriding clear (SRCLR, RCLR) inputs are provided for both the shift and storage register. A serial output (QH’) is provided for cascading.

Both the shift register (SRCLK) and storage register (RCLK) clocks are positive edge triggered. If both clocks are connected together, the shift register is one count pulse ahead of the storage register.