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. The HCTS299MS utilizes advanced CMOS/SOS technology to achieve high-speed operation. This device is a member of radiation hardened, high-speed, CMOS/SOS Logic Family with TTL input compatibility.