The Intersil HCTS299MS is a Radiation Hardened 8-bit shift/ storage register with three-state bus interface capability. The register has four synchronous operating modes controlled by the two select inputs (S0, S1). The mode select, the serial data (DS0, DS7) and the parallel data (IO0 - IO7) respond only to the low to high transition of the clock (CP) pulse. S0, S1 and the data inputs must be one set up time period prior to the clocks positive transition. The master reset (MR) is an asynchronous active low input.