The MAS281 Microprocessor is a MIL-STD-1750A (Notice 1), 16-bit Central Processing Unit (CPU). It consists of three CMOS/SOS large-scale integration (LSI) chips: the MA17501 Execution Unit (EU), the MA17502 Control Unit (CU), and the MA17503 Interrupt Unit (IU). These three units can be mounted on, and interconnected within a 64-pin ceramic substrate. The microprocessor is also available as a 3-chip set without the ceramic substrate (see ordering information on page 55).

FEATURES
■ MIL-STD-1750A 16-Bit Microprocessor
■ Full Performance over Military Temperature Range (-55°C to + 125°C)
■ Radiation Hard CMOS/SOS Technology
■ Performance Optimised Architecture
    - Parallel Multiplier/Accumulator
    - 32-bit Barrel Shifter
    - Instruction Pre-Fetch
    - Multi-Port Register File
■ Implements MlL-STD-1750AOptions
    - Timers A and B
    - Trigger-Go Counter
    - Start-Up ROM Interface
■ 64 K-word Address Space Expandable to 1 M-word with Optional MMU